h = 11.5 m, R = 5 km → θ = 2.3 mrad · f = 2 → N = 4.6 → recognition ✓, identification ✗
Performance chainASEO07 #13
MRTD → f′ → N → TTPF(N/N50) → P(D/R/I)
MRTD: smallest ΔT required (low is good)
TTPF: cycles → probability of success
N50: cycles needed for 50% success
6 · Laser & NVG Exam Review #22, #29
Laser rangefinderER #22
R = c · t2
c = 3×10⁸ m/s
t: round-trip time
Divide by 2 = the path is travelled twice
t = 20 µs → 3×10⁸ × 20×10⁻⁶ / 2 = 3 km R = 1.5 km → t = 2R/c = 10 µs
⚠ Don't forget to divide by 2
NVG distance ruleER #29
Dark: ×2 · Clear: ÷2
Dark night → real = perceived × 2
Clear night → real = perceived ÷ 2
Clear night, perceived 800 m → 400 m · Dark, 300 m → 600 m
Good / Bad table (when high)ER #25
Abbreviation
Stands for
If high
SNR
Signal to Noise Ratio
GOOD
CTF
Contrast Transfer Function
GOOD
MTF
Modulation Transfer Function
GOOD
SITF
Signal Intensity Transfer Function
GOOD
QE
Quantum Efficiency
GOOD
NETD
Noise Equivalent Temperature Difference
BAD
NEI
Noise Equivalent Irradiance
BAD
NEP
Noise Equivalent Power
BAD
CTFeye
Contrast Threshold Function
BAD
MRTD
Minimum Resolvable Temperature Difference
BAD
Spectral bandsER #2
Band
Range
Use / energy
UV
0.1–0.4 µm
missile plume (MAWS)
VIS
0.4–0.7 µm
daytime imaging · reflected
NIR
0.7–1.0 µm
low light, contrast · reflected
SWIR
1–3 µm
haze/smoke, material discrimination · reflected
MWIR
3–5 µm
hot targets, engines, exhaust · emitted
LWIR
8–12 µm
people, vehicles, cool targets · emitted
M-E-L radiometric quantitiesASEO01 #5
Symbol
Meaning
Unit
Q
total energy
J
Φ
energy per unit time
W
M (Exitance)
leaving a surface, all directions
W/m²
E (Irradiance)
arriving at the sensor
W/m²
L (Radiance)
narrow beam in a given direction
W/(m²·sr)
Photometric unitsASEO01 #6
Quantity
Meaning
Unit
Luminous flux
total perceived light
lumen (lm)
Luminous intensity
flux in a given direction
candela (cd)
Illuminance
light falling on a surface (lux meter)
lux (lx = lm/m²)
Luminance
perceived brightness of a surface
cd/m²
Vision typesASEO01 #6
Type
Cell
Peak · K
Note
Photopic (day)
cones
555 nm · 683 lm/W
colour, sharpness
Mesopic
both
mixed
NVIS operations
Scotopic (night)
rods
507 nm · 1700 lm/W
no colour, sensitive to blue-green
Resolution typesER #10
Type
Question
Spatial
How small a detail can I see? (lp/mm)
Spectral
Can I separate different wavelengths?
Temporal
How often do I capture an image?
Radiometric
Can I separate small brightness differences?
Exposure triangleER #14
Setting
What it controls
Side effect
Aperture (f/#)
light entering
small f/# → shallow depth of field
Shutter speed
exposure time
slow → motion blur; fast → freezes a jet
ISO
sensitivity (gain)
high ISO → noise; low ISO for bright conditions
Zoom · Filter · CoatingER #9, #15
Concept
How it works
Result
Digital zoom
crops and enlarges pixels
resolution loss
Optical zoom
changes focal length with lenses
full resolution
Coating
thin film on the lens surface
reduces reflection/glare
Filter
separate element in front of the lens
selects which λ passes
Noise typesER #19
Noise
Source
Dark
the detector itself when there is no light
Thermal
energy emitted by surrounding objects (instructor's definition)
1/f (flicker)
low frequency, electronics imperfections
BLIP
IR background radiation → theoretical limit
Shot
random (statistical) arrival of photons
FPN (fixed by NUC)
fixed pattern between pixels
Detector comparisonsER #16–#18
Topic
A
B
CCD vs CMOS
CCD: shared amplifier, low noise, uniform
CMOS: amplifier in every pixel, fast, low power
Photon vs thermal
Photon: has a cut-off, fast, cooled (MCT)
Thermal: independent of λ, uncooled (VOx)
Staring vs scanning
Staring: 2-D array, whole frame at once
Scanning: line by line, with a mirror
NUC
Non-Uniformity Correction
Removes FPN (offset → gain)
Scattering regimes ('the song')ER #21, #26
Regime
Particle
λ dependence
Example
Rayleigh
≪ λ (molecules)
λ⁻⁴ (strong)
blue sky, NIR/SWIR affected more
Mie
≈ λ (haze, smoke)
λ⁻¹…λ⁻² (weak)
whitish haze, loss of contrast
Geometric
≫ λ (rain, fog)
≈ none
white cloud, all bands
Navy vs ArmyER #28
Service
Band
Why
US Navy
MWIR
better over water, high contrast for ship detection
US Army
LWIR
people/vehicles/terrain on land; less affected by smoke and dust
Johnson criteriaER #24
Task
Line pair
Pixels
Question
Detection
1
2
Is something there?
Orientation
–
–
Which way is it facing?
Recognition
4
8
What class? (aircraft)
Identification
7
14
Exactly what? (SR22)
NVG filter classesER #27
Class
Cut-off
Feature
Class A
blocks < 625 nm
highest NIR sensitivity · strict limits on cockpit lighting
Class B
blocks < 665 nm
compatible with colour displays, yellow/red cautions · slightly less NIR
Class C
665 nm + 545 nm passband
'leaky green' → green HUD symbols visible
NVG filter
blocks below the cut-off
the display filter blocks above the cut-off
NVG tube & laser phasesER #20, #23
Order
NVG
Laser
1
Photocathode: photon → electron (detector)
Excitation / pumping
2
MCP: electron multiplication
Population inversion
3
Phosphor: electron → visible photon
Stimulated emission
4
Eyepiece → image
Lasing (resonator + output)
İlerleme
Çalışma Kağıdı
Bölüm 1: Final Exam Review List (25 madde, HIGH IMPORTANT). Bölüm 2: hocanın Exam Review dosyasındaki 29 maddesi. Bölüm 3: 🎯 ABDU FİTİL ({NQ} soru · {NB} BİREBİR · {NT} TAHMİNİ) → Her maddede anahtar cümle, hocanın notu, açıklama, tablo ve şekil var; yanındaki düğme o maddenin sorularını açar.
Bölüm 1 · Final Exam Review List (HIGH IMPORTANT)
F1
Every matter above 0 K radiates
🔑 0 K üstü her şey ışır
Final Exam Review List
Every matter above 0 K radiates
0 K üstündeki her madde EM (termal) radyasyon yayar. Sıcaklık arttıkça toplam güç artar (T⁴) ve tepe dalga boyu kısalır (Wien). IR kamera bu yüzden karanlıkta da görür.
300 K → tepe 9.7 µm (LWIR) · 1000 K → 2.9 µm (MWIR).
Illuminance: yüzeye düşen görünür ışık miktarı, lux = lm/m². Göz duyarlılığıyla ağırlıklıdır. Spektrometre ise her dalga boyundaki enerjiyi (spektral irradiance) ölçer.
What causes it and which wavelengths/colors are more affected
Neden: kırılma indisi n(λ) dalga boyuna bağlıdır (dispersion). Kısa λ (mavi/mor) daha çok kırılır ve merceğe yakın odaklanır. Kırmızı daha az kırılır ve uzakta odaklanır. En çok etkilenen: spektrumun kısa dalga (mavi) ucu.
F10 · Renk sapması: solda kenarlarda mor/yeşil renk saçakları görülüyor (n(λ) farkı), sağda düzeltilmiş hali. En çok etkilenen uç kısa dalga (mavi/mor).
F11
Aperture and F-stop
🔑 Büyük f-sayısı = küçük açıklık
Final Exam Review List
What happens to aperture size when F-stop changes
D = ff/# · ışık ∝ 1(f/#)²
f = 50 mm içinFinal #11
f-stop
Açıklık D
Işık (f/2.8'e göre)
f/2.8
17.9 mm
1
f/4
12.5 mm
½
f/5.6
8.9 mm
¼
f/8
6.25 mm
≈⅛
f-stop sayısı büyür → açıklık küçülür → daha az ışık, daha derin alan derinliği. Her stop ışığı yarıya indirir.
F11 · Pozlama üçgeni: f-sayısı büyüdükçe açıklık küçülür (F32 en küçük, F1.4 en büyük) ve alan derinliği artar. Altta enstantane (hareketi dondurma) ve ISO (hassasiyet–gürültü) karşılığı.
F12
ISO
🔑 ISO ↑ → hassasiyet ↑, gürültü ↑
Final Exam Review List
What does changing ISO cause in a camera?
ISO = sensörün etkin hassasiyeti, yani elektronik kazanç. Yüksek ISO karanlıkta görüntü alır ama gürültü artar. Düşük ISO parlak ortamda temiz görüntü verir. ISO fotonu artırmaz, sinyali ve gürültüyü birlikte yükseltir.
F12 · Aynı gece sahnesi artan ISO ile: görüntü parlar ama gürültü (karıncalanma) da birlikte artar. ISO foton eklemez, sinyali ve gürültüyü birlikte yükseltir.
F13
Optical Coating vs Filter
🔑 Coating = yüzey · Filter = λ seçimi
Final Exam Review List
Difference and purpose
Coating: lens yüzeyinde ince film. Yansımayı ve parlamayı azaltır, iletimi artırır (AR = MgF₂). Filter: lensin önünde ayrı eleman. Hangi dalga boylarının geçeceğini seçer (bandpass, ND, IR-cut).
F13 · Coating lens yüzeyine kaplanan ince filmdir, yansımayı azaltır ve iletimi artırır (AR = MgF₂). Filter ise ayrı bir bileşendir ve hangi dalga boylarının geçeceğini seçer (bandpass, ND, IR-cut).
F14
NUC
🔑 NUC → FPN'yi kaldırır
Final Exam Review List
What is it used for?
Non-Uniformity Correction: IR dedektörde piksellerin farklı tepkisinden doğan fixed-pattern noise'u düzeltir. İki adımda yapılır: offset, sonra gain. Sonuç homojen ve doğru bir termal görüntüdür.
F14 · NUC öncesi ve sonrası: soldaki görüntüde piksellerin farklı tepkisinden doğan fixed-pattern noise, bantlaşma ve homojensizlik var. NUC offset ve gain'i eşitledikten sonra görüntü sahneyi temsil ediyor.
F16 · Dedektör tepkisi: termal dedektör dalga boyundan bağımsız, düz bir tepki verir. Foton dedektörü daha yüksek tepkiye çıkar ama λc (cut-off) dalga boyundan sonra tepkisi sıfırlanır (hν < Eg).
F17
Shot Noise
🔑 Shot = foton varışının rastgeleliği
Final Exam Review List
What is it and why does it occur?
Shot noise, fotonların (ve elektronların) dedektöre rastgele, istatistiksel olarak gelmesinden oluşur. Işık kesintisiz bir akış değil, ayrık parçacıklardan oluşur, bu yüzden sayım dalgalanır. Sinyalle birlikte artar (≈ √N) ve kaldırılamaz. Dışarıdan gelen istenmeyen fotonlar da katkı yapar.
Photocathode ışığı elektrona çevirir, MCP elektronları çoğaltır. Göz elektron göremez, bu yüzden fosfor ekran yükseltilmiş elektronları tekrar görünür ışığa çevirir ve pilotun gördüğü parlak görüntüyü oluşturur. Yeşil fosfor gözün en hassas olduğu bölgeye denk gelir; beyaz fosfor (P45) daha iyi kontrast verir.
Rayleigh (≪ λ, λ⁻⁴, mavi gök) → Mie (≈ λ, pus/duman/aerosol, zayıf seçici) → Geometric (≫ λ, yağmur/sis/kar, seçici değil).
Bulutlar neden beyaz? Ders slaytında (518–519) geometric başlığı altında: büyük damlalar non-selective saçılma yapar ve tüm renkler eşit saçılır. Bazı kaynaklar bunu Mie olarak da anlatır; anahtar kelime non-selective.
NVG'de derinlik algısı zayıftır ve karanlıkta nesneler olduğundan yakın görünür. Karanlık gece: gerçek = algılanan × 2. Açık gece: gerçek = algılanan ÷ 2.
Navy → MWIR: su üzerinde ve nemli deniz havasında daha iyi, gemi kontrastı yüksek (LWIR su buharından daha çok etkilenir). Army → LWIR: karada insan, araç ve arazi için; duman ve tozdan az etkilenir; ~300 K hedeflerin tepe yayılımı LWIR'dedir.
Increasing the focal length decreases the FOV because the lens magnifies a smaller portion of the scene. A shorter focal length captures a wider area → larger FOV.
FOV (Field of View) = sensörün bir anda görebildiği açısal alan. Odak uzunluğu (f) ile ters orantılıdır.
FOV = 2·arctan(d2f) ≈ df
Kısa f → geniş FOV: arama, durumsal farkındalık, az detay.
Uzun f → dar FOV: yüksek büyütme, tanımlama (ID), küçük alan.
Örnek: d = 12 mm → f = 60 mm'de 0.2 rad, f = 120 mm'de 0.1 rad (f iki katına çıkınca FOV yarıya iner).
UV to visual to LWIR and everything in between: SWIR, MWIR, LWIR — from reflected sunlight to emitted thermal radiation.
EO/IR, UV'den LWIR'e kadar tüm bantları kapsar. EO = yansıyan enerji (VIS/NIR/SWIR), IR = yayılan termal enerji (MWIR/LWIR).
Spektral bantlarER #2
Bant
Aralık
Kullanım
UV
0.1–0.4 µm
füze plume
VIS
0.4–0.7 µm
gündüz görüntü
NIR
0.7–1.0 µm
düşük ışık, kontrast
SWIR
1–3 µm
pus/duman, malzeme ayrımı
MWIR
3–5 µm
sıcak hedef, motor, egzoz
LWIR
8–12 µm
insan, araç, soğuk hedef
#3
Why can you see an object with infrared?
🔑 IR = yayılan termal radyasyon · MWIR & LWIR
Hocanın notu (Exam Review)
Thermal radiation — objects emit thermal radiation because of their temperature, even if invisible to the eye.
Spectral band = MWIR, LWIR — thermal radiation from Earth-temperature objects is strongest there.
Mutlak sıfırın (0 K) üstündeki her nesne sıcaklığından dolayı radyasyon yayar. IR sensör bu enerjiyi algılar; görüntü sıcaklık farklarından oluşur. Bu yüzden ışık gerekmez, tam karanlıkta da çalışır.
Sıcak motor/egzoz → tepe kısa dalgaya kayar → MWIR.
MWIR ve LWIR aynı zamanda atmosferik pencere, yani enerji havadan kolayca geçer.
#4
Why do you see colour?
🔑 Siyah = hepsini soğurur · Beyaz = hepsini yansıtır · Renk = koniler
Hocanın notu (Exam Review)
Black / white
Colour is perceived when different visible wavelengths are reflected and detected by the eye's cone cells (red, green, blue). All wavelengths absorbed → black; most reflected equally → white.
Siyah → tüm görünür dalga boylarını soğurur.
Beyaz → tüm dalga boylarını yaklaşık eşit yansıtır.
Kırmızı nesne → sadece kırmızıyı yansıtır, diğerlerini soğurur.
Rengi koniler algılar (gündüz, fovea). Çubuklar gece çalışır ve renk görmez.
Renk, diffuse yansımadan gelir. Specular (ayna gibi) parlama gelen ışığın rengini korur, bu yüzden beyaz görünür.
#5
What is Wien's Law?
🔑 λmax = 2898 / T · T ↑ → λ ↓
Hocanın notu (Exam Review)
Peak wavelength shift inversely proportional with temperature.
As temperature increases the peak shifts to shorter wavelengths; cooler objects peak at longer wavelengths.
λmax = 2898 µm·KT
Hazır değerlerER #5
T
λmax
Bant
300 K
9.7 µm
LWIR
600 K
4.8 µm
MWIR
1000 K
2.9 µm
MWIR sınırı
5800 K (güneş)
0.5 µm
görünür
Üç yasayı karıştırma: Planck = her dalga boyundaki dağılım · Wien = tepe dalga boyu · Stefan–Boltzmann = toplam güç, M = εσT⁴.
T iki katına çıkarsa toplam güç 16 katına çıkar (2⁴).
°C → K: +273 ekle (−8 °C = 265 K → 10.9 µm → LWIR).
#6
Difference between radiometry and photometry
🔑 Radyometri = fizik (W) · Fotometri = göz (lm)
Hocanın notu (Exam Review)
Radiometry measures all EM radiation based purely on physical power or energy, regardless of whether it is visible.
Photometry measures only visible light and weights it by the sensitivity of the human eye — how bright light appears to people.
KarşılaştırmaER #6
Radyometri
Fotometri
Ne ölçer
fiziksel güç/enerji
göze görünen parlaklık
Bant
tüm EM spektrum
sadece görünür (≈380–780 nm)
Ağırlık
yok
V(λ) göz eğrisi
Birim
W, W/m², W/(m²·sr)
lm, lx, cd, cd/m²
Cihaz
spektrometre (Ee)
lux metre (Ev)
Aynı güçte (W) yeşil lamba, mavi ya da kırmızı lambadan daha parlak görünür, çünkü göz 555 nm'de en hassastır.
M-E-L ve fotometrik karşılıklarıASEO01
Radyometrik
Anlamı
Fotometrik
Φ (W)
toplam güç
luminous flux (lm)
I (W/sr)
belirli yöndeki güç
luminous intensity (cd)
E (W/m²)
yüzeye gelen
illuminance (lux)
M (W/m²)
yüzeyden çıkan
luminous exitance (lm/m²)
L (W/(m²·sr))
belirli yönde, birim alan
luminance (cd/m²)
#7
Km versus V(λ) — sensitivity (Day 1 slide 67)
🔑 V(λ) = göz eğrisi (tepe 555) · Km = 683 lm/W
Hocanın notu (Exam Review)
V(λ) is the spectral sensitivity curve of the human eye. Most sensitive around 555 nm (green), less toward red and blue.
Km is the maximum luminous efficacy constant that converts radiometric power to photometric units: 683 lm/W at 555 nm, where V(λ) = 1.
Φv = Km · V(λ) · Φe
Görme rejimleriASEO01
Rejim
Hücre
Tepe
K
Photopic (gündüz, >10 lx)
koniler
555 nm
683 lm/W
Mesopic (NVIS, 0.01–10 lx)
ikisi
karışım
m·683 + (1−m)·1700
Scotopic (gece, <0.01 lx)
çubuklar
507 nm
1700 lm/W
Örnek: 2 W @ 555 nm → 683 × 1 × 2 = 1366 lm.
Örnek: 1 W @ 650 nm (V ≈ 0.3) → 683 × 0.3 ≈ 205 lm (yaklaşık 3× sönük).
V(450) ≈ 0.2 → mavi 5× sönük. Aynı parlaklık için kırmızı/maviye 3–5× daha fazla güç gerekir.
#8
What to measure: spectrometer vs lux meter
🔑 Spektrometre = spektral dağılım · Lux metre = illuminance
Hocanın notu (Exam Review)
Exceedance — spectrometer measures the spectral distribution (energy at each wavelength), used to check spectral content or exceedance of certain bands.
Illuminance — lux meter measures visible light falling on a surface, in lux (lm/m²).
(Hocanın notu: “unclear on answers”)
Kokpit föyüER #8
Cihaz
Ölçtüğü
Birim
Spektrometre
spektral irradiance Ee,λ (380–780 nm), her dalga boyundaki enerji
W/m²/nm
Lux metre
illuminance Ev, yüzeye düşen görünür ışık
lux = lm/m²
Föydeki iş akışı: spektrometre verisi × V(λ) × 683 → hesaplanan lux. Sonra aynı mesafedeki lux metre okumasıyla karşılaştırılır. Farkın nedenleri: hizalama, yansıma, sensör kalibrasyonu.
Ters kare yasası: E = Φ/(4πd²). E'yi 1/d²'ye karşı çizince düz çizgi çıkar. Mesafe 2× olursa aydınlık ¼'e düşer.
Lambertian yüzey: L = ρ·E/π (örnek: ρ = 0.5, E = 314 lx → 50 cd/m²).
#9
Digital versus optical zoom
🔑 Dijital = çözünürlük kaybı · Optik = f değişir
Hocanın notu (Exam Review)
D: lose resolution — digital zoom crops and scales existing pixels → loss of resolution and detail.
O: uses lenses to change focal length — magnifies while keeping full sensor resolution.
Line pair/mm = spatial resolution.
ZoomER #9
Dijital
Optik
Nasıl
pikselleri kırpar + büyütür
lens hareketiyle f değişir
Detay
kazanılmaz, çözünürlük kaybı
gerçek büyütme, tam çözünürlük
FOV
değişmez (sadece kırpma)
f ↑ → FOV ↓
Uzamsal çözünürlük lp/mm (line pair/mm) ile ifade edilir. 1 line pair = 1 siyah + 1 beyaz çizgi. Açısal birimler (cycles/mrad) menzilden bağımsızdır.
#10
What kind of resolution?
🔑 Line pair → spatial resolution
Hocanın notu (Exam Review)
Maybe line pairs above is the answer
Spatial — distinguish small objects/fine detail · Spectral — distinguish wavelengths/colours · Temporal — how often images are captured · Radiometric — distinguish small intensity differences.
Çözünürlük tipleriER #10
Tip
Soru
Örnek
Spatial
ne kadar küçük detay?
lp/mm, GSD, IFOV
Spectral
dalga boylarını ayırabilir miyim?
RGB vs hiperspektral
Temporal
ne sıklıkla görüntü?
kare hızı (Hz)
Radiometric
küçük parlaklık farkı?
ADC bit: 12 bit = 4096 seviye
#11
What is GSD?
🔑 GSD = α × R (radyan × metre)
Hocanın notu (Exam Review)
How much of the ground you see in one pixel — indicates spatial resolution on the ground.
Alpha times R: GSD = α × R (α = angular FOV per pixel, R = distance to the ground).
GSD = α × R · α = IFOV ≈ pf
Örnek 1: α = 120 µrad, R = 6 km → 120×10⁻⁶ × 6000 = 0.72 m.
Örnek 2: p = 15 µm, f = 100 mm → α = 150 µrad → R = 100 m'de GSD = 1.5 cm.
Küçük GSD = daha iyi çözünürlük. R 2× olursa GSD de 2× olur (lineer ilişki, kare değil).
Birimleri çevir: µrad → ×10⁻⁶ rad, km → m.
#12
What is chromatic aberration / which colour focuses first?
🔑 Küçük λ → büyük n → önce (yakında) odaklanır → MAVİ
Hocanın notu (Exam Review)
The smaller λ has a higher index of refraction and therefore converges sooner.
A lens bends different wavelengths by different amounts → colours focus at different points along the axis. Blue (short λ) focuses before red.
Kırılma indisi n(λ) dalga boyuna bağlıdır (dispersion).
Mavi (kısa λ, büyük n) → daha çok kırılır → merceğe yakın odaklanır.
Kırmızı (uzun λ, küçük n) → daha az kırılır → uzakta odaklanır.
Etkisi: kenarlarda renk saçakları, düşük keskinlik. Çözüm: akromatik lens (crown + flint cam) veya ayna (reflektif) optik.
Diğer aberasyonlarla karıştırma: coma = kuyruklu yıldız · astigmatism = yatay/dikey farklı odak · spherical = kenar/merkez ışınları · distortion = eğri çizgiler.
#13
What is the f-number?
🔑 f/# = f / D · D ↑ → f/# ↓ → ışık ↑
Hocanın notu (Exam Review)
F = focal length / lens diameter (F/D) — relative size of the aperture.
As D increases more light is let in → lower f-number, brighter image, shallower depth of field.
f/# = fD · toplanan ışık ∝ 1(f/#)²
Örnek: f = 100 mm, D = 25 mm → f/4.
f/2 → f/4 yapılırsa ışık (2/4)² = ¼'e iner (iki stop).
Küçük f/# → çok ışık, iyi SNR, küçük Airy diski, ama büyük/ağır optik ve sığ alan derinliği.
Tuzak: D/f değil, f/D.
#14
How does the exposure triangle work?
🔑 Aperture = ışık · Shutter = süre (jet) · ISO = hassasiyet/gürültü
Hocanın notu (Exam Review)
F-number (aperture) — how much light enters; lower f-number = more light.
Shutter speed — how long the sensor is exposed; fast freezes a jet, slow gives more light but motion blur.
ISO — how sensitive to light: low ISO for lots of light (less noise), high ISO for low light (more sensitive).
Pozlama üçgeniER #14
Ayar
Kontrol ettiği
Yan etki
Aperture (f/#)
içeri giren ışık
küçük f/# → sığ alan derinliği
Shutter speed
pozlama süresi
yavaş → hareket bulanıklığı
ISO
hassasiyet (elektronik kazanç)
yüksek ISO → gürültü
Derste: ISO aslında elektronik kazançtır ve sinyalle birlikte gürültüyü de yükseltir. Düşük ISO 100–200 gündüz, yüksek ISO 800–6400+ gece.
#15
Filters versus coatings (Optics slide 109)
🔑 Coating = yüzeyde · Filter = önde, λ seçer
Hocanın notu (Exam Review)
Coating — on the lens; changes how light interacts with the surface (reduce reflection/glare, improve transmission).
Filter — in front of the lens; separate element controlling which wavelengths pass through.
Filtre vs kaplamaER #15
Coating
Filter
Nerede
lens yüzeyinde ince film
lensin önünde ayrı eleman
Görev
yansıma/parlama azaltma, iletim artırma
hangi λ geçer seçme/engelleme
Örnek
AR (MgF₂, yıkıcı girişim), altın ayna (IR)
interference, absorption, ND, heat-absorbing (IR engeller)
ortama enerji verilir (flaş lamba, diyot, elektrik), elektronlar üst seviyeye çıkar
Population inversion
üst seviyede alttakinden daha fazla atom birikir (metastable seviye tuzak gibi çalışır)
Stimulated emission
gelen foton, aynı frekans, faz ve yönde ikinci bir foton üretir
Lasing
rezonatör (aynalar) ışığı ileri-geri gezdirip yükseltir, kısmi aynadan ışın çıkar
Spontaneous emission (~10⁻⁸ s) rastgele fotonlar üretir, stimulated emission ise koherent fotonlar. 4 seviyeli lazer daha verimlidir çünkü alt seviye hızla boşalır. Q-switching kısa (ns) ve çok güçlü darbe üretir.
#24
What is the Johnson criteria?
🔑 1 – 4 – 7 line pair
Hocanın notu (Exam Review)
A standard relating image resolution to target detection, recognition and identification performance.
MRTD frekansla yükselir; aşağıdaki eğri daha iyidir. Titreşim ve blur eğriyi yukarı kaydırır.
MTF frekansla düşer; blur ve titreşim MTF'i düşürür. Sistem MTF'i bileşenlerin çarpımıdır.
#26
Song — Rayleigh, Mie, Geometric
🔑 Küçük → orta → büyük parçacık
Hocanın notu (Exam Review)
Do Rayleigh – Mie – Geometric
Saçılma rejimleriER #26
Rejim
Parçacık
λ bağımlılığı
Örnek
Rayleigh
≪ λ (N₂, O₂ molekülleri)
λ⁻⁴ (güçlü)
mavi gök, kızıl gün batımı
Mie
≈ λ (pus, duman, aerosol)
λ⁻¹…λ⁻² (zayıf)
beyazımsı pus, kontrast kaybı
Geometric
≫ λ (yağmur, sis damlası, kar)
≈ bağımsız
beyaz bulut, tüm bantlar benzer etkilenir
Sıra = parçacık büyüdükçe: Rayleigh → Mie → Geometric.
Bulutlar neden beyaz? Ders slaytı (518–519) bunu Geometric başlığı altında verir: büyük damlalar non-selective saçılma yapar, tüm renkler eşit saçılır. Bazı kaynaklar bulut damlalarını Mie'nin üst ucu olarak anlatır; ortak anahtar kelime non-selective. Sis için ders “strong Mie scattering by water droplets” der.
#27
NVG filter vs display filter
🔑 NVG filtresi altını, ekran filtresi üstünü keser · A 625 · B 665 · C 665+545
Hocanın notu (Exam Review)
Filter for NVG removes wavelengths below XXX — blocks visible light so the photocathode mainly detects NIR.
Display NVG filter removes wavelengths above XXX — prevents emitted light from interfering with the NVG.
Sonuç: pilot kokpiti görür, NVG kokpit ışığıyla doymaz (blooming olmaz).
#28
Why does the US Navy prefer MWIR and the Army LWIR?
🔑 Navy = MWIR (deniz) · Army = LWIR (kara)
Hocanın notu (Exam Review)
Navy → MWIR: performs better over water surfaces and at moderate distances; higher contrast for ship detection and navigation in maritime environments.
Army → LWIR: excels in terrestrial environments (humans, vehicles, terrain, day or night); less affected by scattering, smoke and dust.
Navy vs ArmyER #28
Kuvvet
Bant
Neden
US Navy
MWIR
su üzerinde daha iyi · gemi kontrastı · nemli havada LWIR su buharından daha çok etkilenir
US Army
LWIR
karada insan/araç/arazi · duman ve tozdan az etkilenir · ~300 K tepe yayılımı
#29
NVG distance rule of thumb
🔑 Karanlık ×2 · Açık ÷2
Hocanın notu (Exam Review)
Dark night: real distance = perceived distance × 2
Clear night: real distance = perceived distance / 2
Karanlık gece, algılanan 300 m → gerçek 600 m.
Açık gece, algılanan 800 m → gerçek 400 m.
NVG kol uçuşunda mesafe ve yaklaşma hızını yanlış tahmin etmek çarpışmaların ana nedenlerindendir.
Bölüm 3 · ABDU FİTİL (49 soru)
Hocanın ses kaydından (Audio 13.23.00) ve ders notlarından çıkarılan 48 çoktan seçmeli soru. BİREBİR = soru kökünü hoca doğrudan söyledi ya da açıkça sınav sorusu olarak belirtti (22 soru). TAHMİNİ = hocanın ipucundan veya ders notlarından kuruldu ve ders materyaliyle doğrulandı (26 soru). Hocanın belirttiği format: 25 çoktan seçmeli soru, tek doğru cevap, 2 saat.
What is the difference between diffuse and specular reflection?
BİREBİR
✅ Diffuse reflection spreads energy over many directions; specular reflection concentrates it near the mirror direction
Kanıt / kaynak
Audio 13.23.00, 00:24–00:42
Ders: ASEO01
Diffuse: pürüzlü yüzey → enerji her yöne dağılır, malzemeyle etkileşir → nesnenin rengi (kirazın kırmızısı). Specular: pürüzsüz yüzey → ayna yönünde toplanır (geliş açısı = yansıma açısı) → beyaz parlama. Her iki yansıma türü her bantta olabilir.
Yanlış şıklar
They are identical processes
Diffuse reflection preserves a single direction; specular spreads equally
Diffuse reflection occurs only in IR; specular only in visible
A5
How does the peak emission wavelength change as absolute temperature increases?
BİREBİR
✅ It shifts to shorter wavelengths
Kanıt / kaynak
Audio 13.23.00, 00:42–01:06
Ders: ASEO01
Wien: λmax = b / T (b = 2898 µm·K). T artınca λmaxküçülür → tepe kısa dalgaya kayar. 300 K → 9.7 µm (LWIR), 1000 K → 2.9 µm (MWIR), güneş 5800 K → 0.5 µm.
Yanlış şıklar
It remains fixed
It becomes independent of emissivity and temperature
It shifts to longer wavelengths
A7
Why can two lights with equal radiant power but different colours appear to have different brightness?
BİREBİR
✅ The eye has a wavelength-dependent luminous efficiency V(λ)
Kanıt / kaynak
Audio 13.23.00, 01:20–01:37
Ders: ASEO01
Fotometri, radyan gücü gözün spektral duyarlılığı V(λ) ile ağırlıklandırır (tepe 555 nm). 1 W yeşil ≈ 683 lm, 1 W kırmızı (650 nm) ≈ 205 lm. Radyan güç (W) göze göre ağırlıklı değildir.
Yanlış şıklar
Radiant power is already weighted by the eye
Brightness depends only on aperture diameter
All colours travel at different speeds in air
A8
What does a lux meter measure?
BİREBİR
✅ Illuminance in lux
Kanıt / kaynak
Audio 13.23.00, 01:37–02:03
Ders: ASEO01
Lux metre, yüzeye birim alan başına düşen ışık akısını ölçer: illuminance, lux = lm/m². Luminance (cd/m²) yüzeyden belirli yönde gelen parlaklıktır; radiance ve radiant flux radyometrik büyüklüklerdir.
Yanlış şıklar
Radiance in watts per square metre per steradian
Radiant flux in watts
Luminance in candela per square metre
A9
Is a lux measurement based on human-eye response or unweighted radiometric power?
BİREBİR
✅ Human-eye-weighted photometric response
Kanıt / kaynak
Audio 13.23.00, 01:54–02:03
Ders: ASEO01
Lux fotometrik bir birimdir → içinde V(λ) göz ağırlığı vardır. Ağırlıksız fiziksel güç W/m² (irradiance) ile ifade edilir ve spektrometre/radyometre ile ölçülür.
Yanlış şıklar
Thermal detector response only
Unweighted radiometric power
Atmospheric transmission only
A12
When the f-stop number is increased, what happens to the aperture diameter?
BİREBİR
✅ It decreases
Kanıt / kaynak
Audio 13.23.00, 02:32–02:42
Ders: ASEO02
f/# = f / D → D = f / (f/#). Sabit odak uzunluğunda f-sayısı büyüdükçe açıklık küçülür. f = 50 mm: f/2.8 → 17.9 mm, f/8 → 6.25 mm.
Yanlış şıklar
It remains unchanged
It becomes equal to focal length
It increases
A14
What does increasing the ISO setting on a camera do?
BİREBİR
✅ Increases electronic gain and apparent brightness but also amplifies noise
Kanıt / kaynak
Audio 13.23.00, 02:48–02:56
Ders: ASEO02
ISO = elektronik kazanç. Lensin topladığı ışığı artırmaz; sinyali ve gürültüyü birlikte yükseltir. Karanlıkta görüntü parlaklaşır ama karıncalanma artar. Shot noise fizikseldir, ISO ile yok olmaz.
Yanlış şıklar
Changes optical wavelength
Increases physical aperture diameter
Eliminates shot noise
A15
What is the main difference between an optical filter and an optical coating?
BİREBİR
✅ A filter is a wavelength-selective component; a coating is a thin film deposited on a surface to control reflection/transmission
Kanıt / kaynak
Audio 13.23.00, 02:56–03:36 · hoca “I quote” dedi
Ders: ASEO02
Filter: ayrı bir bileşen, hangi dalga boylarının geçeceğini seçer (bandpass, ND, IR-cut). Coating: yüzeye kaplanan ince film, yansıma/iletimi kontrol eder (AR = MgF₂). Not: bazı girişim filtreleri kaplama yığınlarından yapılır. Hoca bu soruyu “I quote” diyerek okudu.
Yanlış şıklar
A coating selects pixels; a filter corrects detector gain
A filter is always on the target; a coating is only in the atmosphere
There is no difference
A16
What is NUC and why is it required?
BİREBİR
✅ Non-Uniformity Correction; it equalizes pixel responses so the image represents the scene rather than detector variation
Kanıt / kaynak
Audio 13.23.00, 03:37–03:54
Ders: ASEO03
NUC = Non-Uniformity Correction. IR dedektörde her pikselin offset ve gain'i farklıdır → sabit desen gürültüsü (FPN). NUC bunları eşitler, böylece görüntü dedektör farklarını değil sahneyi gösterir.
Yanlış şıklar
Numerical Unit Conversion; it changes watts to lux
Night Uniformity Coating; it reduces lens reflection
Noise Utility Control; it increases optical gain
A17
What does CCD stand for?
BİREBİR
✅ Charge-Coupled Device
Kanıt / kaynak
Audio 13.23.00, 03:54–03:59
Ders: ASEO03
CCD = Charge-Coupled Device. Yük pikselden piksele “coupled” şekilde aktarılır ve ortak bir çıkış yükselticisinden okunur.
Yanlış şıklar
Current-Controlled Detector
Charge-Converted Diode
Coherent Camera Display
A18
What does CMOS stand for?
BİREBİR
✅ Complementary Metal-Oxide-Semiconductor
Kanıt / kaynak
Audio 13.23.00, 03:59–04:06
Ders: ASEO03
CMOS = Complementary Metal-Oxide-Semiconductor. Her pikselde kendi yükselticisi olan (active pixel) sensör teknolojisi: hızlı, düşük güç, ucuz.
Yanlış şıklar
Coherent Multi-Output System
Controlled Metal Optical Sensor
Complementary Mirror Optics System
A20
What is the main difference between photon and thermal detectors?
BİREBİR
✅ Photon detectors directly create electrical carriers; thermal detectors first convert absorbed power into a temperature change
Kanıt / kaynak
Audio 13.23.00, 04:19–04:25
Ders: ASEO03
Photon: foton → doğrudan elektron/boşluk (kuantum geçişi), cut-off var, hızlı, genelde soğutmalı (MCT, InSb). Thermal: soğrulan güç → sıcaklık değişimi → direnç/voltaj değişimi, λ'dan büyük ölçüde bağımsız, soğutmasız (VOx mikrobolometre). Son şık ters.
Yanlış şıklar
Thermal detectors count photons directly; photon detectors only heat up
Thermal detectors operate only in visible light
Photon detectors never need cooling; thermal detectors always do
A21
What is photon shot noise?
BİREBİR
✅ Random fluctuation in photon arrival rate
Kanıt / kaynak
Audio 13.23.00, 04:25–04:46
Ders: ASEO03
Işık ayrık fotonlardan oluşur ve varışları istatistiksel (Poisson) dağılır → sayım dalgalanır. Sinyale bağlıdır (≈ √N) ve kaldırılamaz. Sıcaklık kaynaklı direnç gürültüsü = Johnson/thermal; piksel kazanç hatası = FPN.
Yanlış şıklar
Resistance noise caused only by temperature
Fixed-pattern pixel gain error
Random mirror vibration
A22
Why is a phosphor screen used in image-intensifier NVGs?
BİREBİR
✅ To convert amplified electrons back into visible photons
Kanıt / kaynak
Audio 13.23.00, 04:46–05:04
Ders: ASEO03
Göz elektron göremez. MCP'de çoğaltılan elektronlar fosfor ekrana çarpar ve görünür fotonlar üretir → pilotun gördüğü yeşil/beyaz görüntü.
Yanlış şıklar
To convert visible photons directly into radio waves
To cool the microchannel plate
To absorb all green light
A24
Which is generally more affected by molecular atmospheric absorption: visible EO or thermal IR?
BİREBİR
✅ Thermal IR, because gases have strong wavelength-selective molecular absorption bands
Kanıt / kaynak
Audio 13.23.00, 05:17–05:27
Ders: ASEO04
IR iletimi H₂O, CO₂ (4.3 µm), O₃ (9.6 µm) gibi gazların moleküler soğurma bantlarıyla şekillenir → atmosferik pencereler (3–5, 8–12 µm). Görünür bant ise daha çok saçılma ile sınırlıdır. Rayleigh saçılmadır, soğurma değildir.
Yanlış şıklar
Neither is affected by the atmosphere
Both are always affected equally
Visible EO, because Rayleigh scattering is absorption
A25
How does atmospheric turbulence affect different spectral bands?
BİREBİR
✅ Shorter wavelengths are generally affected more strongly; longer-wave IR is relatively less sensitive
Kanıt / kaynak
Audio 13.23.00, 05:17–05:27
Ders: ASEO04
Turbulence dalga cephesinde yol farkı yaratır; bunun dalga boyuna oranı λ büyüdükçe küçülür (faz bozulması ∝ 1/λ). Bu yüzden görünür > MWIR > LWIR sırasıyla etkilenir. SIMTERM'de de fırtınada MWIR menzili LWIR'den çok düştü.
Yanlış şıklar
Turbulence affects only ultraviolet
LWIR is always affected more than visible light
All bands are affected identically
A30
For MRTD, is a high value or a low value better?
BİREBİR
✅ Low; less temperature contrast is needed to resolve the pattern
Kanıt / kaynak
Audio 13.23.00, 06:02–06:09
Ders: ASEO07
MRTD = 4-bar deseni çözmek için gereken en küçük ΔT. Ne kadar küçükse sistem o kadar az kontrastla çözer → düşük MRTD iyi. Termal hassasiyet ve uzamsal çözünürlüğü birleştirir; grafikte alttaki eğri daha iyi.
Yanlış şıklar
High; more temperature contrast is always better
Zero only at all spatial frequencies
Neither; MRTD does not describe performance
A31
For NETD, is a high value or a low value better?
BİREBİR
✅ Low; the sensor can distinguish a smaller temperature difference
Kanıt / kaynak
Audio 13.23.00, 06:07–06:14
Ders: ASEO07
NETD = sinyalin gürültüye eşit olduğu (SNR = 1) sahne sıcaklık farkı. Düşük NETD → daha küçük ΔT ayırt edilir → daha iyi termal hassasiyet. NETD = Vnoise / SITF (örn. 3 mV / 60 mV/K = 50 mK).
Yanlış şıklar
High only for photon detectors
High; more noise improves sensitivity
Neither; NETD is a laser metric
A32
For signal-to-noise ratio, is a high value or a low value better?
BİREBİR
✅ High; the useful signal is stronger relative to noise
Kanıt / kaynak
Audio 13.23.00, 06:14–06:19
Ders: ASEO07
SNR = sinyal / gürültü. Yüksek SNR → faydalı sinyal gürültüden belirgin → daha iyi tespit ve daha temiz görüntü. İyi/kötü tablosunda SNR “yüksek = İYİ” tarafında.
Yanlış şıklar
Zero; signal and noise should cancel
The value has no performance meaning
Low; noise should dominate
A33
For Noise Equivalent Irradiance (NEI), is a high value or a low value better?
BİREBİR
✅ Low; less input irradiance is required to equal system noise
Kanıt / kaynak
Audio 13.23.00, 06:21–06:40
Ders: ASEO07
NEI = SNR = 1 veren giriş irradyansı. Daha az girişle gürültü seviyesine ulaşılıyorsa sistem zayıf sinyalleri görebilir → düşük NEI iyi. Hafıza: adında “Noise Equivalent” geçen her şey düşük olmalı (NETD, NEI, NEP).
Yanlış şıklar
High for EO and low for IR
High; more required input means greater sensitivity
Either; NEI measures only display brightness
A34
For the System Intensity Transfer Function (SITF), is a high value or a low value generally better?
BİREBİR
✅ High; a given scene contrast produces a larger output signal
Kanıt / kaynak
Audio 13.23.00, 06:21–06:40
Ders: ASEO07
SITF = ΔV / ΔT, yani sahne kontrastını çıkış sinyaline çevirme kazancı. Yüksek SITF → aynı ΔT daha büyük sinyal verir. Ayrıca NETD = Vnoise/SITF olduğundan SITF büyüdükçe NETD küçülür.
Yanlış şıklar
SITF describes noise only
Low; weak signal transfer is preferred
Zero; no scene signal should reach the output
A48
Which statement best explains the common operational preference for MWIR in naval applications and LWIR in land-force applications?
BİREBİR
✅ Naval forces prefer MWIR because it is less sensitive to water-vapour absorption; land forces prefer LWIR because it is less affected by scattering from smoke, haze and dust and images ambient-temperature terrain well
Kanıt / kaynak
Hoca açıkça soru olarak belirtti (öğrenci bildirimi) · ASEO04 slayt 102–106, ASEO08 slayt 28
Ders: ASEO04 / ASEO08
Navy → MWIR: nemli deniz yolunda su buharı soğurmasına daha az duyarlı, gemi kontrastı yüksek. Army → LWIR: duman, pus ve tozdan kaynaklanan saçılmadan daha az etkilenir; ~300 K arazi ve hedeflerin tepe yayılımı LWIR'dedir.
Yanlış şıklar
Naval forces prefer LWIR only because it detects visible colours; land forces prefer MWIR because it requires daylight
Both services always use SWIR because MWIR and LWIR cannot operate at night
The preference is unrelated to atmosphere, target temperature or background contrast
TAHMİNİ · 26 soruHocanın ipucundan veya ders notlarından kuruldu
A1
Which equation gives the horizontal field of view for detector width d and focal length f?
TAHMİNİ
✅ FOV = 2 arctan(d / 2f)
Kanıt / kaynak
Audio 13.23.00, 00:00–00:07
Ders: ASEO02
Tam FOV, dedektör genişliğinin yarısının gördüğü yarım açının iki katıdır: tan(θ/2) = (d/2)/f → FOV = 2·arctan(d/2f). Küçük açıda FOV ≈ d/f. λ/d kırınım açısıdır; d×f ve f/d boyut olarak yanlıştır.
Yanlış şıklar
FOV = λ / d
FOV = d × f
FOV = f / d
A2
What is the approximate relationship between ground sample distance (GSD), range R and instantaneous field of view (IFOV)?
TAHMİNİ
✅ GSD = R × IFOV
Kanıt / kaynak
Audio 13.23.00, 02:03–02:34
Ders: ASEO02
Küçük açı yaklaşımında bir pikselin yere izdüşümü = menzil × açısal boyut: GSD = R × IFOV (IFOV radyan). Örnek: 120 µrad × 6000 m = 0.72 m. Menzil 2× → GSD 2×.
Yanlış şıklar
GSD = R / IFOV
GSD = IFOV / R
GSD = f-number × wavelength
A3
Which atmospheric processes redirect or remove radiation from the sensor path?
TAHMİNİ
✅ Scattering redirects it; absorption converts it into internal molecular energy
Kanıt / kaynak
Audio 13.23.00, 00:07–00:23
Ders: ASEO04
Saçılma (scattering) enerjiyi yok etmez, yönünü değiştirir. Soğurma (absorption) ise enerjiyi moleküllerin iç enerjisine (ısıya) çevirerek ışından çıkarır. İkisi birlikte sönümleme katsayısını oluşturur: γ = saçılma + soğurma, τ = e−γR.
Yanlış şıklar
Refraction destroys photons; reflection creates energy
Emission removes energy without any interaction
Diffraction absorbs all wavelengths equally
A6
According to the Stefan–Boltzmann law, what happens to total emitted power per unit area as temperature increases?
TAHMİNİ
✅ It increases in proportion to T⁴
Kanıt / kaynak
Audio 13.23.00, 00:48–01:06
Ders: ASEO01
Kara cisim için radyan çıkış M = σT⁴ (gerçek yüzeyde εσT⁴). T iki katına çıkarsa güç 2⁴ = 16 kat artar. Eğri altındaki toplam alan = S-B; tepe noktası = Wien.
Yanlış şıklar
It decreases as 1/T
It increases linearly with T
It depends only on wavelength
A10
What causes chromatic aberration?
TAHMİNİ
✅ Refractive index varies with wavelength, so colours focus at different positions
Kanıt / kaynak
Audio 13.23.00, 02:22–02:31
Ders: ASEO02
Dispersiyon: kırılma indisi n(λ) dalga boyuna bağlıdır → farklı renkler farklı miktarda kırılır ve optik eksende farklı noktalarda odaklanır. Çözüm: akromatik lens veya reflektif optik.
Yanlış şıklar
All wavelengths diffract identically
The aperture stop blocks off-axis rays
Detector pixels have unequal gain
A11
Which visible wavelengths are generally refracted most strongly by ordinary glass?
TAHMİNİ
✅ Shorter blue/violet wavelengths
Kanıt / kaynak
Audio 13.23.00, 02:22–02:31
Ders: ASEO02
Normal dispersiyonda kısa dalga boyunda n daha büyüktür → mavi/mor en çok kırılır ve merceğe en yakın odaklanır. Kırmızı en az kırılır, en uzakta odaklanır.
Yanlış şıklar
Only green at 555 nm
Longer red wavelengths
All visible wavelengths equally
A13
Which combination best describes increasing the f-number?
TAHMİNİ
✅ Less collected light, larger depth of field, and eventually more diffraction blur
Kanıt / kaynak
Audio 13.23.00, 02:32–02:42
Ders: ASEO02
f-sayısını büyütmek (stopping down): açıklık küçülür → ışık ∝ 1/(f/#)² azalır, alan derinliği artar, ve çok küçük açıklıkta Airy diski (r = 1.22λf/D) büyüdüğü için kırınım bulanıklığı artar.
Yanlış şıklar
No change to exposure or aperture
More light and shallower depth of field
More light with no resolution effect
A19
Which statement correctly compares CCD and CMOS readout?
TAHMİNİ
✅ CCD transfers charge pixel-to-pixel to an output; CMOS normally uses per-pixel active readout
Kanıt / kaynak
Audio 13.23.00, 04:06–04:19
Ders: ASEO03
Hoca “CCD ve CMOS'un nasıl farklı çalıştığına dair bir soru var” dedi. CCD: yük çip boyunca kaydırılır → tek/ortak çıkış → düşük gürültü, yüksek homojenlik. CMOS: her pikselde yükseltici → hızlı, az güç. Tuzak şık bu ikisini ters yazıyor. İkisi de staring dizidir.
Yanlış şıklar
Both require mechanical scanning
CMOS transfers all charge through a single output and CCD uses per-pixel amplifiers
Neither is a staring array
A23
Which sequence correctly describes an image-intensifier NVG?
Hoca vurguladı: NVG fotonla başlar, fotonla biter, arada elektron kullanır. Photocathode (foton→e⁻) → MCP (e⁻ çoğaltma) → fosfor (e⁻→foton) → göz merceği.
Yanlış şıklar
Photons → sound → electrons
Thermal photons → laser → CCD only
Electrons → photons → thermal heating → radio signal
A26
Which list best represents the essential stages of laser action?
TAHMİNİ
✅ Pumping, population inversion, stimulated emission, resonator feedback, output coupling
Kanıt / kaynak
Audio 13.23.00, 05:32–05:38
Ders: ASEO05
Hoca “lazerin aşamalarını/fazlarını çalışın” dedi. Pumping (enerji ver) → population inversion (üstte daha çok atom) → stimulated emission (özdeş foton) → rezonatör geri beslemesi (aynalar arası yükseltme) → çıkış (kısmi ayna). Diğer şıklar başka konuların terimleri.
Yanlış şıklar
Absorption, scattering, refraction, display
Detection, recognition, identification only
NUC, sampling, blooming, phosphor
A27
Why is population inversion necessary for laser amplification?
TAHMİNİ
✅ Stimulated emission must exceed absorption
Kanıt / kaynak
Audio 13.23.00, 05:32–05:38
Ders: ASEO05
Bir foton hem uyarılmış emisyona hem soğurmaya yol açabilir. Net kazanç için üst seviyedeki atom sayısı alttakinden fazla olmalı → uyarılmış emisyon soğurmayı geçer. Spontane emisyon tamamen yok edilmez; lazeri başlatan tohum fotonları o sağlar.
Yanlış şıklar
All atoms must remain in the ground state
Spontaneous emission must be eliminated completely
The cavity must contain no photons
A28
According to the Johnson criteria, what distinguishes detection, recognition and identification?
TAHMİNİ
✅ Presence; target class; specific type/identity
Kanıt / kaynak
Audio 13.23.00, 05:43–05:51
Ders: ASEO07
Hoca Johnson kriterlerini üst seviyede bilmenizi istedi. Detection: bir şey var mı? · Recognition: hangi sınıf (tank/uçak)? · Identification: tam tipi ne (SR22, T-72)?
Yanlış şıklar
Colour; range; speed
Search; tracking; laser firing
Temperature; pressure; humidity
A29
Which approximate Johnson detail requirements were taught for detection, recognition and identification?
TAHMİNİ
✅ About 1, 4 and 7 line pairs respectively
Kanıt / kaynak
Audio 13.23.00, 05:43–05:51
Ders: ASEO07
Görev zorlaştıkça hedef üzerinde daha fazla çözülebilir çevrim gerekir: D = 1, R = 4, I = 7 line pair (2 / 8 / 14 piksel). Ters sıra (7-4-1) tuzaktır. Hafıza: 1-4-7.
Yanlış şıklar
Exactly 1 line pair for all tasks
About 7, 4 and 1 line pairs respectively
About 10, 20 and 30 line pairs
A35
Sensor A has lower MRTD, lower NETD, lower NEI, higher SITF and higher SNR than Sensor B. Which is the better choice, all else equal?
TAHMİNİ
✅ Sensor A
Kanıt / kaynak
Audio 13.23.00, 05:51–06:40
Ders: ASEO07
Hoca açıkça “bir dizi değere bakarak sensör seçme sorusu gelecek” dedi. Kural: MRTD, NETD, NEI → düşük iyi · SITF, SNR → yüksek iyi. Sensor A beş kriterin hepsinde iyi tarafta → Sensor A.
Yanlış şıklar
They must be identical
No performance comparison is possible from these metrics
Sensor B
A36
Rayleigh scattering dominates when particle size is:
All matter above absolute zero has which radiative property?
TAHMİNİ
✅ It emits electromagnetic radiation
Kanıt / kaynak
Sınav Hazırlık notu 1
Ders: ASEO01
Parçacıkların termal hareketi nedeniyle 0 K üstündeki her cisim EM radyasyon yayar. 273 K (0 °C) özel bir sınır değildir; radyasyon ortam gerektirmez, vakumda da yayılır. IR kameranın karanlıkta görmesinin nedeni budur.
Yanlış şıklar
It emits radiation only above 273 K
It emits only if illuminated by the Sun
It cannot radiate in a vacuum
A42
Which sequence gives the commonly used EO/IR spectral bands in increasing wavelength?
Artan dalga boyu: VIS → NIR → SWIR → MWIR → LWIR. Not: bu kaynakta NIR 0.7–1.4 µm, LWIR 8–14 µm verilmiş; sitedeki diğer tablolar NIR 0.7–1.0, LWIR 8–12 µm kullanıyor. İkisi de yaygın tanımlardır, sıra aynıdır. Ters sıra (LWIR→VIS) azalan dalga boyudur.
Yanlış şıklar
All bands occupy the same wavelengths
LWIR; MWIR; SWIR; NIR; visible
Visible 3–5 µm; NIR 8–14 µm; MWIR 0.4–0.7 µm
A43
For a fixed detector size, what happens when focal length and optical magnification increase?
TAHMİNİ
✅ Field of view decreases
Kanıt / kaynak
Sınav Hazırlık notu 3
Ders: ASEO02
Sabit dedektörde FOV ≈ d/f → f büyüdükçe FOV küçülür, büyütme artar. Örnek: 50 → 200 mm = 4× büyütme, FOV 4 kat daralır. Uzun f = tanımlama, kısa f = arama.
Yanlış şıklar
Aperture diameter must become zero
Field of view remains constant
Field of view increases
A44
Under humid atmospheric conditions, which thermal band is generally most affected by water-vapour absorption among SWIR, MWIR and LWIR?
TAHMİNİ
✅ LWIR
Kanıt / kaynak
Sınav Hazırlık notu 19
Ders: ASEO04
Ders slaytlarına göre nem/su buharı soğurması özellikle LWIR'de önemlidir (MWIR su buharına daha az duyarlı). Dikkat: soru saçılma sorsaydı cevap kısa dalga (SWIR) olurdu. “Tamamen opak” gibi mutlak ifadeler yanlıştır; gerçek iletim yol ve dalga boyuna bağlıdır.
Yanlış şıklar
MWIR is always completely opaque
SWIR is always completely opaque
All three are affected identically
A45
Which statement correctly distinguishes absorption, spontaneous emission and stimulated emission in laser physics?
TAHMİNİ
✅ Absorption raises an atom; spontaneous emission is random; stimulated emission produces a matching photon
Kanıt / kaynak
Sınav Hazırlık notu 20
Ders: ASEO05
Absorption: foton soğrulur, atom üst seviyeye çıkar. Spontaneous: kendiliğinden düşüş (~10⁻⁸ s), rastgele yön/faz. Stimulated: gelen foton, aynı frekans, faz ve yönde ikinci foton üretir; gelen foton da devam eder → koherent yükseltme.
Yanlış şıklar
All three processes produce identical random photons
Stimulated emission destroys the incident photon without replacement
Absorption lowers an atom while spontaneous emission raises it
A46
Which matching of laser property and meaning is correct?
Monochromaticity = dar spektrum (tek dalga boyu) · Coherence = dalgalar arasında sabit faz ilişkisi · Directionality = çok düşük ıraksama (<0.5 mrad). Diğer şıklar bu anlamları karıştırıyor.
Monochromaticity – high divergence; coherence – many colours; directionality – random propagation
A47
According to the NVG distance-illusion rule of thumb, which relation is correct?
TAHMİNİ
✅ Dark night: real distance = perceived distance × 2; clear night: real distance = perceived distance / 2
Kanıt / kaynak
ASEO08 Tactical Advantages and Limitations, slayt 23 · öğrencinin bildirdiği konu
Ders: ASEO08
Slayt 23: Karanlık gece ×2, açık gece ÷2. Örnek: karanlıkta algılanan 300 m → gerçek 600 m; açık gecede algılanan 800 m → gerçek 400 m. İkinci şık bunu ters yazan tuzaktır.
Yanlış şıklar
Dark night: real distance = perceived distance / 2; clear night: real distance = perceived distance × 2
Real distance always equals perceived distance, regardless of night conditions
Real distance = perceived distance × 2 on both dark and clear nights
A49
Which radiation law states that the peak-emission wavelength is inversely proportional to absolute temperature (λmax × T = b)?
Wien: λmax × T = b (2898 µm·K) → T artınca tepe kısa dalgaya kayar. Karıştırma: Stefan–Boltzmann = toplam güç ∝ T⁴ · Beer–Lambert = atmosferik iletim e−γR · Snell = kırılma n₁sinθ₁ = n₂sinθ₂.
Yanlış şıklar
Stefan–Boltzmann Law
Beer–Lambert Law
Snell's Law
Study Sheet
Part 1: Final Exam Review List (25 items, HIGH IMPORTANT). Part 2: the 29 items from the instructor's Exam Review file. Part 3: 🎯 ABDU FİTİL ({NQ} questions · {NB} BİREBİR · {NT} TAHMİNİ) → Each item has a key sentence, the instructor's note, an explanation, tables and figures; the button next to it opens that item's questions.
Part 1 · Final Exam Review List (HIGH IMPORTANT)
F1
Every matter above 0 K radiates
🔑 Everything above 0 K radiates
Final Exam Review List
Every matter above 0 K radiates
Every matter above 0 K emits EM (thermal) radiation. As temperature rises, total power increases (T⁴) and the peak wavelength gets shorter (Wien). That is why an IR camera sees in the dark too.
300 K → peak 9.7 µm (LWIR) · 1000 K → 2.9 µm (MWIR).
Radiation needs no medium; it also travels through vacuum.
Objects that do not emit light are seen from every angle thanks to diffuse reflection. Laser-guided weapons also track the diffuse reflection from the target.
F6
Stefan–Boltzmann Equation
🔑 M = εσT⁴ · T×2 → ×16
Final Exam Review List
Total thermal energy radiated per unit area ∝ T⁴
M = ε · σ · T4
σ = 5.67×10⁻⁸ W·m⁻²·K⁻⁴ · ε = emissivity (1 for a blackbody).
T × 2 → M × 16. Example: 300 K → 600 K, emitted power increases 16 times.
Example: T = 1000 K, ε = 0.95 → M = 0.95 × 5.67×10⁻⁸ × 10¹² ≈ 5.4 kW/m².
Planck = spectral distribution · Wien = peak · S-B = total (area under the curve).
Illuminance: the amount of visible light falling on a surface, lux = lm/m². It is weighted by the eye's sensitivity. A spectrometer, on the other hand, measures the energy at each wavelength (spectral irradiance).
What causes it and which wavelengths/colors are more affected
Cause: the refractive index n(λ) depends on wavelength (dispersion). Short λ (blue/violet) bends more and focuses close to the lens. Red bends less and focuses farther away. Most affected: the short-wave (blue) end of the spectrum.
F10 · Chromatic aberration: on the left, purple/green colour fringes along the edges (because of n(λ)); on the right, the corrected version. The most affected end is the short wave (blue/violet).
F11
Aperture and F-stop
🔑 Large f-number = small aperture
Final Exam Review List
What happens to aperture size when F-stop changes
D = ff/# · light ∝ 1(f/#)²
For f = 50 mmFinal #11
f-stop
Aperture D
Light (relative to f/2.8)
f/2.8
17.9 mm
1
f/4
12.5 mm
½
f/5.6
8.9 mm
¼
f/8
6.25 mm
≈⅛
f-stop number increases → aperture gets smaller → less light, deeper depth of field. Each stop halves the light.
F11 · Exposure triangle: as the f-number grows the aperture shrinks (F32 smallest, F1.4 largest) and depth of field increases. Below: shutter speed (freezing motion) and ISO (sensitivity vs noise).
F12
ISO
🔑 ISO ↑ → sensitivity ↑, noise ↑
Final Exam Review List
What does changing ISO cause in a camera?
ISO = the sensor's effective sensitivity, i.e. electronic gain. High ISO captures images in the dark but noise increases. Low ISO gives a clean image in bright conditions. ISO does not add photons; it amplifies signal and noise together.
F12 · The same night scene at increasing ISO: the image gets brighter but noise (grain) grows with it. ISO adds no photons; it amplifies signal and noise together.
F13
Optical Coating vs Filter
🔑 Coating = surface · Filter = λ selection
Final Exam Review List
Difference and purpose
Coating: a thin film on the lens surface. Reduces reflection and glare, increases transmission (AR = MgF₂). Filter: a separate element in front of the lens. Selects which wavelengths pass (bandpass, ND, IR-cut).
F13 · A coating is a thin film deposited on the lens surface; it reduces reflection and increases transmission (AR = MgF₂). A filter is a separate component that selects which wavelengths pass (bandpass, ND, IR-cut).
F14
NUC
🔑 NUC → removes FPN
Final Exam Review List
What is it used for?
Non-Uniformity Correction: corrects the fixed-pattern noise caused by the different responses of pixels in an IR detector. It is done in two steps: offset, then gain. The result is a uniform, accurate thermal image.
F14 · Before and after NUC: on the left, fixed-pattern noise, banding and non-uniformity caused by different pixel responses. After NUC equalizes offset and gain, the image represents the scene.
F16 · Detector response: a thermal detector gives a flat response independent of wavelength. A photon detector reaches a higher response but drops to zero beyond the λc (cut-off) wavelength (hν < Eg).
F17
Shot Noise
🔑 Shot = randomness of photon arrival
Final Exam Review List
What is it and why does it occur?
Shot noise comes from photons (and electrons) arriving at the detector randomly, statistically. Light is not a continuous flow but discrete particles, so the count fluctuates. It grows with the signal (≈ √N) and cannot be removed. Unwanted photons from outside also contribute.
The photocathode converts light into electrons and the MCP multiplies them. The eye cannot see electrons, so the phosphor screen converts the amplified electrons back into visible light, forming the bright image the pilot sees. Green phosphor matches the region where the eye is most sensitive; white phosphor (P45) gives better contrast.
Why are clouds white? On the course slide (518–519) under Geometric: large droplets cause non-selective scattering and all colours scatter equally. Some sources describe this as Mie; the keyword is non-selective.
Depth perception is poor with NVGs, and in the dark objects look closer than they are. Dark night: real = perceived × 2. Clear night: real = perceived ÷ 2.
Navy → MWIR: better over water and in humid maritime air, high ship contrast (LWIR is affected more by water vapour). Army → LWIR: for people, vehicles and terrain on land; less affected by smoke and dust; ~300 K targets peak in the LWIR.
Increasing the focal length decreases the FOV because the lens magnifies a smaller portion of the scene. A shorter focal length captures a wider area → larger FOV.
FOV (Field of View) = the angular area the sensor can see at once. It is inversely proportional to focal length (f).
FOV = 2·arctan(d2f) ≈ df
Short f → wide FOV: search, situational awareness, little detail.
Long f → narrow FOV: high magnification, identification (ID), small area.
Example: d = 12 mm → 0.2 rad at f = 60 mm, 0.1 rad at f = 120 mm (doubling f halves the FOV).
UV to visual to LWIR and everything in between: SWIR, MWIR, LWIR — from reflected sunlight to emitted thermal radiation.
EO/IR covers all bands from UV to LWIR. EO = reflected energy (VIS/NIR/SWIR), IR = emitted thermal energy (MWIR/LWIR).
Spectral bandsER #2
Band
Range
Use
UV
0.1–0.4 µm
missile plume
VIS
0.4–0.7 µm
daytime imaging
NIR
0.7–1.0 µm
low light, contrast
SWIR
1–3 µm
haze/smoke, material discrimination
MWIR
3–5 µm
hot targets, engines, exhaust
LWIR
8–12 µm
people, vehicles, cool targets
#3
Why can you see an object with infrared?
🔑 IR = emitted thermal radiation · MWIR & LWIR
Instructor's note (Exam Review)
Thermal radiation — objects emit thermal radiation because of their temperature, even if invisible to the eye.
Spectral band = MWIR, LWIR — thermal radiation from Earth-temperature objects is strongest there.
Every object above absolute zero (0 K) emits radiation because of its temperature. The IR sensor detects this energy; the image is formed from temperature differences. So no light is needed and it works in total darkness.
Hot engine/exhaust → peak shifts to shorter wavelength → MWIR.
MWIR and LWIR are also atmospheric windows, meaning the energy passes easily through the air.
#4
Why do you see colour?
🔑 Black = absorbs all · White = reflects all · Colour = cones
Instructor's note (Exam Review)
Black / white
Colour is perceived when different visible wavelengths are reflected and detected by the eye's cone cells (red, green, blue). All wavelengths absorbed → black; most reflected equally → white.
Black → absorbs all visible wavelengths.
White → reflects all wavelengths roughly equally.
Red object → reflects only red and absorbs the others.
Colour is sensed by the cones (daytime, fovea). Rods work at night and do not see colour.
Colour comes from diffuse reflection. Specular (mirror-like) glint keeps the colour of the incident light, so it looks white.
#5
What is Wien's Law?
🔑 λmax = 2898 / T · T ↑ → λ ↓
Instructor's note (Exam Review)
Peak wavelength shift inversely proportional with temperature.
As temperature increases the peak shifts to shorter wavelengths; cooler objects peak at longer wavelengths.
λmax = 2898 µm·KT
Ready valuesER #5
T
λmax
Band
300 K
9.7 µm
LWIR
600 K
4.8 µm
MWIR
1000 K
2.9 µm
MWIR edge
5800 K (sun)
0.5 µm
visible
Don't mix up the three laws: Planck = distribution over every wavelength · Wien = peak wavelength · Stefan–Boltzmann = total power, M = εσT⁴.
Radiometry measures all EM radiation based purely on physical power or energy, regardless of whether it is visible.
Photometry measures only visible light and weights it by the sensitivity of the human eye — how bright light appears to people.
ComparisonER #6
Radiometry
Photometry
Measures
physical power/energy
brightness as seen by the eye
Band
entire EM spectrum
visible only (≈380–780 nm)
Weighting
none
V(λ) eye curve
Unit
W, W/m², W/(m²·sr)
lm, lx, cd, cd/m²
Instrument
spectrometer (Ee)
lux meter (Ev)
At the same power (W), a green lamp looks brighter than a blue or red lamp, because the eye is most sensitive at 555 nm.
M-E-L and photometric equivalentsASEO01
Radiometric
Meaning
Photometric
Φ (W)
total power
luminous flux (lm)
I (W/sr)
power in a given direction
luminous intensity (cd)
E (W/m²)
incident on a surface
illuminance (lux)
M (W/m²)
leaving a surface
luminous exitance (lm/m²)
L (W/(m²·sr))
in a given direction, per unit area
luminance (cd/m²)
#7
Km versus V(λ) — sensitivity (Day 1 slide 67)
🔑 V(λ) = eye curve (peak 555) · Km = 683 lm/W
Instructor's note (Exam Review)
V(λ) is the spectral sensitivity curve of the human eye. Most sensitive around 555 nm (green), less toward red and blue.
Km is the maximum luminous efficacy constant that converts radiometric power to photometric units: 683 lm/W at 555 nm, where V(λ) = 1.
Φv = Km · V(λ) · Φe
Vision regimesASEO01
Regime
Cell
Peak
K
Photopic (day, >10 lx)
cones
555 nm
683 lm/W
Mesopic (NVIS, 0.01–10 lx)
both
mixed
m·683 + (1−m)·1700
Scotopic (night, <0.01 lx)
rods
507 nm
1700 lm/W
Example: 2 W @ 555 nm → 683 × 1 × 2 = 1366 lm.
Example: 1 W @ 650 nm (V ≈ 0.3) → 683 × 0.3 ≈ 205 lm (about 3× dimmer).
V(450) ≈ 0.2 → blue is 5× dimmer. Red/blue needs 3–5× more power for the same brightness.
#8
What to measure: spectrometer vs lux meter
🔑 Spectrometer = spectral distribution · Lux meter = illuminance
Instructor's note (Exam Review)
Exceedance — spectrometer measures the spectral distribution (energy at each wavelength), used to check spectral content or exceedance of certain bands.
Illuminance — lux meter measures visible light falling on a surface, in lux (lm/m²).
(Instructor's note: “unclear on answers”)
Cockpit worksheetER #8
Instrument
Measures
Unit
Spectrometer
spectral irradiance Ee,λ (380–780 nm), energy at each wavelength
W/m²/nm
Lux meter
illuminance Ev, visible light falling on a surface
lux = lm/m²
Worksheet workflow: spectrometer data × V(λ) × 683 → calculated lux. Then it is compared with the lux meter reading at the same distance. Reasons for the difference: alignment, reflections, sensor calibration.
Inverse square law: E = Φ/(4πd²). Plotting E against 1/d² gives a straight line. If the distance doubles, illuminance drops to ¼.
Lambertian surface: L = ρ·E/π (example: ρ = 0.5, E = 314 lx → 50 cd/m²).
#9
Digital versus optical zoom
🔑 Digital = resolution loss · Optical = f changes
Instructor's note (Exam Review)
D: lose resolution — digital zoom crops and scales existing pixels → loss of resolution and detail.
O: uses lenses to change focal length — magnifies while keeping full sensor resolution.
Line pair/mm = spatial resolution.
ZoomER #9
Digital
Optical
How
crops + enlarges pixels
f changes by moving lenses
Detail
no gain, resolution loss
true magnification, full resolution
FOV
unchanged (crop only)
f ↑ → FOV ↓
Spatial resolution is expressed in lp/mm (line pairs/mm). 1 line pair = 1 black + 1 white line. Angular units (cycles/mrad) are independent of range.
#10
What kind of resolution?
🔑 Line pair → spatial resolution
Instructor's note (Exam Review)
Maybe line pairs above is the answer
Spatial — distinguish small objects/fine detail · Spectral — distinguish wavelengths/colours · Temporal — how often images are captured · Radiometric — distinguish small intensity differences.
Resolution typesER #10
Type
Question
Example
Spatial
how small a detail?
lp/mm, GSD, IFOV
Spectral
can I separate wavelengths?
RGB vs hyperspectral
Temporal
how often an image?
frame rate (Hz)
Radiometric
small brightness difference?
ADC bits: 12 bit = 4096 levels
#11
What is GSD?
🔑 GSD = α × R (radians × metres)
Instructor's note (Exam Review)
How much of the ground you see in one pixel — indicates spatial resolution on the ground.
Alpha times R: GSD = α × R (α = angular FOV per pixel, R = distance to the ground).
GSD = α × R · α = IFOV ≈ pf
Example 1: α = 120 µrad, R = 6 km → 120×10⁻⁶ × 6000 = 0.72 m.
Example 2: p = 15 µm, f = 100 mm → α = 150 µrad → at R = 100 m, GSD = 1.5 cm.
Smaller GSD = better resolution. If R doubles, GSD doubles too (linear relationship, not squared).
Convert units: µrad → ×10⁻⁶ rad, km → m.
#12
What is chromatic aberration / which colour focuses first?
🔑 Small λ → large n → focuses first (closer) → BLUE
Instructor's note (Exam Review)
The smaller λ has a higher index of refraction and therefore converges sooner.
A lens bends different wavelengths by different amounts → colours focus at different points along the axis. Blue (short λ) focuses before red.
The refractive index n(λ) depends on wavelength (dispersion).
Blue (short λ, large n) → bends more → focuses close to the lens.
Red (long λ, small n) → bends less → focuses farther away.
Effect: colour fringes at edges, lower sharpness. Fix: achromatic lens (crown + flint glass) or mirror (reflective) optics.
Don't confuse with other aberrations: coma = comet tail · astigmatism = different horizontal/vertical focus · spherical = edge/centre rays · distortion = curved lines.
#13
What is the f-number?
🔑 f/# = f / D · D ↑ → f/# ↓ → light ↑
Instructor's note (Exam Review)
F = focal length / lens diameter (F/D) — relative size of the aperture.
As D increases more light is let in → lower f-number, brighter image, shallower depth of field.
f/# = fD · collected light ∝ 1(f/#)²
Example: f = 100 mm, D = 25 mm → f/4.
Going from f/2 → f/4, light drops to (2/4)² = ¼ (two stops).
Small f/# → lots of light, good SNR, small Airy disk, but large/heavy optics and shallow depth of field.
Trap: it is f/D, not D/f.
#14
How does the exposure triangle work?
🔑 Aperture = light · Shutter = time (jet) · ISO = sensitivity/noise
Instructor's note (Exam Review)
F-number (aperture) — how much light enters; lower f-number = more light.
Shutter speed — how long the sensor is exposed; fast freezes a jet, slow gives more light but motion blur.
ISO — how sensitive to light: low ISO for lots of light (less noise), high ISO for low light (more sensitive).
Exposure triangleER #14
Setting
Controls
Side effect
Aperture (f/#)
light entering
small f/# → shallow depth of field
Shutter speed
exposure time
slow → motion blur
ISO
sensitivity (electronic gain)
high ISO → noise
In class: ISO is really electronic gain and raises noise together with the signal. Low ISO 100–200 for day, high ISO 800–6400+ for night.
#15
Filters versus coatings (Optics slide 109)
🔑 Coating = on the surface · Filter = in front, selects λ
Instructor's note (Exam Review)
Coating — on the lens; changes how light interacts with the surface (reduce reflection/glare, improve transmission).
Filter — in front of the lens; separate element controlling which wavelengths pass through.
Filter vs coatingER #15
Coating
Filter
Where
thin film on the lens surface
separate element in front of the lens
Task
reduce reflection/glare, increase transmission
select/block which λ passes
Example
AR (MgF₂, destructive interference), gold mirror (IR)
energy is given to the medium (flash lamp, diode, electricity), electrons rise to an upper level
Population inversion
more atoms accumulate at the upper level than the lower one (the metastable level acts like a trap)
Stimulated emission
an incoming photon produces a second photon with the same frequency, phase and direction
Lasing
the resonator (mirrors) bounces the light back and forth and amplifies it; the beam exits through the partial mirror
Spontaneous emission (~10⁻⁸ s) produces random photons, while stimulated emission produces coherent photons. A 4-level laser is more efficient because the lower level empties quickly. Q-switching produces short (ns), very powerful pulses.
#24
What is the Johnson criteria?
🔑 1 – 4 – 7 line pair
Instructor's note (Exam Review)
A standard relating image resolution to target detection, recognition and identification performance.
MRTD rises with frequency; the lower curve is better. Vibration and blur shift the curve up.
MTF falls with frequency; blur and vibration lower the MTF. System MTF is the product of its components.
#26
Song — Rayleigh, Mie, Geometric
🔑 Small → medium → large particles
Instructor's note (Exam Review)
Do Rayleigh – Mie – Geometric
Scattering regimesER #26
Regime
Particle
λ dependence
Example
Rayleigh
≪ λ (N₂, O₂ molecules)
λ⁻⁴ (strong)
blue sky, red sunset
Mie
≈ λ (haze, smoke, aerosol)
λ⁻¹…λ⁻² (weak)
whitish haze, loss of contrast
Geometric
≫ λ (rain, fog droplets, snow)
≈ independent
white cloud, all bands affected similarly
Order = as particles get larger: Rayleigh → Mie → Geometric.
Why are clouds white? The course slide (518–519) puts this under Geometric: large droplets cause non-selective scattering, all colours scatter equally. Some sources describe cloud droplets as the upper end of Mie; the shared keyword is non-selective. For fog, the course says “strong Mie scattering by water droplets”.
#27
NVG filter vs display filter
🔑 NVG filter cuts below, display filter cuts above · A 625 · B 665 · C 665+545
Instructor's note (Exam Review)
Filter for NVG removes wavelengths below XXX — blocks visible light so the photocathode mainly detects NIR.
Display NVG filter removes wavelengths above XXX — prevents emitted light from interfering with the NVG.
Class B: blocks < 665 nm · better with multi-colour displays, yellow/red cautions · slightly less NIR.
Class C (“leaky green”): 665 nm cut-off + narrow 545 nm passband → green HUD symbology visible.
NVG filter classesER #27
Class
Cut-off
Pro
Con
A
625 nm
highest NIR, ideal in very dark conditions
strict limits on cockpit lighting
B
665 nm
colour displays, yellow/red cautions
slightly less NIR
C
665 nm + 545 nm passband
green HUD visible (fighter jets)
—
NVG filter → blocks below the cut-off (short wave, visible).
Display/cockpit filter → blocks above the cut-off (red/NIR).
Result: the pilot sees the cockpit and the NVG is not saturated by cockpit light (no blooming).
#28
Why does the US Navy prefer MWIR and the Army LWIR?
🔑 Navy = MWIR (sea) · Army = LWIR (land)
Instructor's note (Exam Review)
Navy → MWIR: performs better over water surfaces and at moderate distances; higher contrast for ship detection and navigation in maritime environments.
Army → LWIR: excels in terrestrial environments (humans, vehicles, terrain, day or night); less affected by scattering, smoke and dust.
Navy vs ArmyER #28
Service
Band
Why
US Navy
MWIR
better over water · ship contrast · in humid air LWIR is affected more by water vapour
US Army
LWIR
people/vehicles/terrain on land · less affected by smoke and dust · ~300 K peak emission
#29
NVG distance rule of thumb
🔑 Dark ×2 · Clear ÷2
Instructor's note (Exam Review)
Dark night: real distance = perceived distance × 2
Clear night: real distance = perceived distance / 2
Dark night, perceived 300 m → real 600 m.
Clear night, perceived 800 m → real 400 m.
Misjudging distance and closure rate in NVG formation flight is one of the main causes of collisions.
Part 3 · ABDU FİTİL (49 questions)
48 multiple-choice questions taken from the instructor's audio (Audio 13.23.00) and class notes. BİREBİR (verbatim) = the stem was stated directly by the instructor or explicitly identified as an exam question (22 questions). TAHMİNİ (predicted) = reconstructed from an instructor hint or class notes and verified against the course material (26 questions). Instructor-stated format: 25 multiple-choice questions, one correct answer, 2 hours.
BİREBİR · 22 questionsStated directly by the instructor / identified as an exam question
A4
What is the difference between diffuse and specular reflection?
BİREBİR
✅ Diffuse reflection spreads energy over many directions; specular reflection concentrates it near the mirror direction
Evidence / source
Audio 13.23.00, 00:24–00:42
Course: ASEO01
Diffuse: rough surface → energy spreads in all directions and interacts with the material → the object's colour (the cherry's red). Specular: smooth surface → concentrated in the mirror direction (angle in = angle out) → white glint. Both types can occur in any band.
Wrong options
They are identical processes
Diffuse reflection preserves a single direction; specular spreads equally
Diffuse reflection occurs only in IR; specular only in visible
A5
How does the peak emission wavelength change as absolute temperature increases?
BİREBİR
✅ It shifts to shorter wavelengths
Evidence / source
Audio 13.23.00, 00:42–01:06
Course: ASEO01
Wien: λmax = b / T (b = 2898 µm·K). As T rises, λmaxgets smaller → the peak shifts to shorter wavelengths. 300 K → 9.7 µm (LWIR), 1000 K → 2.9 µm (MWIR), sun 5800 K → 0.5 µm.
Wrong options
It remains fixed
It becomes independent of emissivity and temperature
It shifts to longer wavelengths
A7
Why can two lights with equal radiant power but different colours appear to have different brightness?
BİREBİR
✅ The eye has a wavelength-dependent luminous efficiency V(λ)
Evidence / source
Audio 13.23.00, 01:20–01:37
Course: ASEO01
Photometry weights radiant power by the eye's spectral sensitivity V(λ) (peak at 555 nm). 1 W green ≈ 683 lm, 1 W red (650 nm) ≈ 205 lm. Radiant power (W) is not eye-weighted.
Wrong options
Radiant power is already weighted by the eye
Brightness depends only on aperture diameter
All colours travel at different speeds in air
A8
What does a lux meter measure?
BİREBİR
✅ Illuminance in lux
Evidence / source
Audio 13.23.00, 01:37–02:03
Course: ASEO01
A lux meter measures luminous flux incident per unit area: illuminance, lux = lm/m². Luminance (cd/m²) is brightness leaving a surface in a direction; radiance and radiant flux are radiometric quantities.
Wrong options
Radiance in watts per square metre per steradian
Radiant flux in watts
Luminance in candela per square metre
A9
Is a lux measurement based on human-eye response or unweighted radiometric power?
BİREBİR
✅ Human-eye-weighted photometric response
Evidence / source
Audio 13.23.00, 01:54–02:03
Course: ASEO01
Lux is a photometric unit → it includes V(λ) eye weighting. Unweighted physical power is expressed in W/m² (irradiance) and is measured with a spectrometer/radiometer.
Wrong options
Thermal detector response only
Unweighted radiometric power
Atmospheric transmission only
A12
When the f-stop number is increased, what happens to the aperture diameter?
BİREBİR
✅ It decreases
Evidence / source
Audio 13.23.00, 02:32–02:42
Course: ASEO02
f/# = f / D → D = f / (f/#). At fixed focal length, a larger f-number means a smaller aperture. f = 50 mm: f/2.8 → 17.9 mm, f/8 → 6.25 mm.
Wrong options
It remains unchanged
It becomes equal to focal length
It increases
A14
What does increasing the ISO setting on a camera do?
BİREBİR
✅ Increases electronic gain and apparent brightness but also amplifies noise
Evidence / source
Audio 13.23.00, 02:48–02:56
Course: ASEO02
ISO = electronic gain. It does not increase the light collected by the lens; it amplifies signal and noise together. The image gets brighter in the dark but grainier. Shot noise is physical and ISO cannot remove it.
Wrong options
Changes optical wavelength
Increases physical aperture diameter
Eliminates shot noise
A15
What is the main difference between an optical filter and an optical coating?
BİREBİR
✅ A filter is a wavelength-selective component; a coating is a thin film deposited on a surface to control reflection/transmission
Evidence / source
Audio 13.23.00, 02:56–03:36 · instructor said “I quote”
Course: ASEO02
Filter: a separate component that selects which wavelengths pass (bandpass, ND, IR-cut). Coating: a thin film deposited on a surface to control reflection/transmission (AR = MgF₂). Note: some interference filters are built from coating stacks. The instructor read this one out saying “I quote”.
Wrong options
A coating selects pixels; a filter corrects detector gain
A filter is always on the target; a coating is only in the atmosphere
There is no difference
A16
What is NUC and why is it required?
BİREBİR
✅ Non-Uniformity Correction; it equalizes pixel responses so the image represents the scene rather than detector variation
Evidence / source
Audio 13.23.00, 03:37–03:54
Course: ASEO03
NUC = Non-Uniformity Correction. In an IR detector each pixel has a different offset and gain → fixed-pattern noise (FPN). NUC equalizes them so the image shows the scene, not detector variation.
Wrong options
Numerical Unit Conversion; it changes watts to lux
Night Uniformity Coating; it reduces lens reflection
Noise Utility Control; it increases optical gain
A17
What does CCD stand for?
BİREBİR
✅ Charge-Coupled Device
Evidence / source
Audio 13.23.00, 03:54–03:59
Course: ASEO03
CCD = Charge-Coupled Device. Charge is passed pixel to pixel in a “coupled” manner and read out through a shared output amplifier.
Wrong options
Current-Controlled Detector
Charge-Converted Diode
Coherent Camera Display
A18
What does CMOS stand for?
BİREBİR
✅ Complementary Metal-Oxide-Semiconductor
Evidence / source
Audio 13.23.00, 03:59–04:06
Course: ASEO03
CMOS = Complementary Metal-Oxide-Semiconductor. Sensor technology with an amplifier in every pixel (active pixel): fast, low power, cheap.
Wrong options
Coherent Multi-Output System
Controlled Metal Optical Sensor
Complementary Mirror Optics System
A20
What is the main difference between photon and thermal detectors?
BİREBİR
✅ Photon detectors directly create electrical carriers; thermal detectors first convert absorbed power into a temperature change
Evidence / source
Audio 13.23.00, 04:19–04:25
Course: ASEO03
Photon: photon → directly an electron/hole (quantum transition), has a cut-off, fast, usually cooled (MCT, InSb). Thermal: absorbed power → temperature change → resistance/voltage change, largely wavelength-independent, uncooled (VOx microbolometer). The last option is reversed.
Wrong options
Thermal detectors count photons directly; photon detectors only heat up
Thermal detectors operate only in visible light
Photon detectors never need cooling; thermal detectors always do
A21
What is photon shot noise?
BİREBİR
✅ Random fluctuation in photon arrival rate
Evidence / source
Audio 13.23.00, 04:25–04:46
Course: ASEO03
Light is made of discrete photons whose arrivals are statistical (Poisson) → the count fluctuates. It depends on the signal (≈ √N) and cannot be removed. Temperature-driven resistor noise = Johnson/thermal; pixel gain error = FPN.
Wrong options
Resistance noise caused only by temperature
Fixed-pattern pixel gain error
Random mirror vibration
A22
Why is a phosphor screen used in image-intensifier NVGs?
BİREBİR
✅ To convert amplified electrons back into visible photons
Evidence / source
Audio 13.23.00, 04:46–05:04
Course: ASEO03
The eye cannot see electrons. Electrons multiplied in the MCP hit the phosphor screen and produce visible photons → the green/white image the pilot sees.
Wrong options
To convert visible photons directly into radio waves
To cool the microchannel plate
To absorb all green light
A24
Which is generally more affected by molecular atmospheric absorption: visible EO or thermal IR?
BİREBİR
✅ Thermal IR, because gases have strong wavelength-selective molecular absorption bands
Evidence / source
Audio 13.23.00, 05:17–05:27
Course: ASEO04
IR transmission is shaped by the molecular absorption bands of gases such as H₂O, CO₂ (4.3 µm) and O₃ (9.6 µm) → atmospheric windows (3–5, 8–12 µm). The visible band is limited mostly by scattering. Rayleigh is scattering, not absorption.
Wrong options
Neither is affected by the atmosphere
Both are always affected equally
Visible EO, because Rayleigh scattering is absorption
A25
How does atmospheric turbulence affect different spectral bands?
BİREBİR
✅ Shorter wavelengths are generally affected more strongly; longer-wave IR is relatively less sensitive
Evidence / source
Audio 13.23.00, 05:17–05:27
Course: ASEO04
Turbulence creates path differences across the wavefront; their ratio to wavelength shrinks as λ grows (phase distortion ∝ 1/λ). So visible > MWIR > LWIR in sensitivity. In SIMTERM too, MWIR range dropped more than LWIR in the storm.
Wrong options
Turbulence affects only ultraviolet
LWIR is always affected more than visible light
All bands are affected identically
A30
For MRTD, is a high value or a low value better?
BİREBİR
✅ Low; less temperature contrast is needed to resolve the pattern
Evidence / source
Audio 13.23.00, 06:02–06:09
Course: ASEO07
MRTD = the smallest ΔT required to resolve a 4-bar pattern. The smaller it is, the less contrast the system needs → low MRTD is good. It combines thermal sensitivity and spatial resolution; the lower curve on the plot is better.
Wrong options
High; more temperature contrast is always better
Zero only at all spatial frequencies
Neither; MRTD does not describe performance
A31
For NETD, is a high value or a low value better?
BİREBİR
✅ Low; the sensor can distinguish a smaller temperature difference
Evidence / source
Audio 13.23.00, 06:07–06:14
Course: ASEO07
NETD = the scene temperature difference at which signal equals noise (SNR = 1). Low NETD → smaller ΔT can be distinguished → better thermal sensitivity. NETD = Vnoise / SITF (e.g. 3 mV / 60 mV/K = 50 mK).
Wrong options
High only for photon detectors
High; more noise improves sensitivity
Neither; NETD is a laser metric
A32
For signal-to-noise ratio, is a high value or a low value better?
BİREBİR
✅ High; the useful signal is stronger relative to noise
Evidence / source
Audio 13.23.00, 06:14–06:19
Course: ASEO07
SNR = signal / noise. High SNR → the useful signal stands out from noise → better detection and a cleaner image. In the good/bad table SNR is on the “high = GOOD” side.
Wrong options
Zero; signal and noise should cancel
The value has no performance meaning
Low; noise should dominate
A33
For Noise Equivalent Irradiance (NEI), is a high value or a low value better?
BİREBİR
✅ Low; less input irradiance is required to equal system noise
Evidence / source
Audio 13.23.00, 06:21–06:40
Course: ASEO07
NEI = the input irradiance that gives SNR = 1. If less input reaches the noise level, the system can see weak signals → low NEI is good. Memory: anything named “Noise Equivalent” should be low (NETD, NEI, NEP).
Wrong options
High for EO and low for IR
High; more required input means greater sensitivity
Either; NEI measures only display brightness
A34
For the System Intensity Transfer Function (SITF), is a high value or a low value generally better?
BİREBİR
✅ High; a given scene contrast produces a larger output signal
Evidence / source
Audio 13.23.00, 06:21–06:40
Course: ASEO07
SITF = ΔV / ΔT, the gain converting scene contrast into output signal. High SITF → the same ΔT gives a larger signal. Also, since NETD = Vnoise/SITF, a larger SITF gives a smaller NETD.
Wrong options
SITF describes noise only
Low; weak signal transfer is preferred
Zero; no scene signal should reach the output
A48
Which statement best explains the common operational preference for MWIR in naval applications and LWIR in land-force applications?
BİREBİR
✅ Naval forces prefer MWIR because it is less sensitive to water-vapour absorption; land forces prefer LWIR because it is less affected by scattering from smoke, haze and dust and images ambient-temperature terrain well
Evidence / source
Instructor explicitly identified this as a question (student report) · ASEO04 slide 102–106, ASEO08 slide 28
Course: ASEO04 / ASEO08
Navy → MWIR: less sensitive to water-vapour absorption over humid maritime paths, high ship contrast. Army → LWIR: less affected by scattering from smoke, haze and dust; ~300 K terrain and targets peak in the LWIR.
Wrong options
Naval forces prefer LWIR only because it detects visible colours; land forces prefer MWIR because it requires daylight
Both services always use SWIR because MWIR and LWIR cannot operate at night
The preference is unrelated to atmosphere, target temperature or background contrast
TAHMİNİ · 26 questionsReconstructed from an instructor hint or class notes
A1
Which equation gives the horizontal field of view for detector width d and focal length f?
TAHMİNİ
✅ FOV = 2 arctan(d / 2f)
Evidence / source
Audio 13.23.00, 00:00–00:07
Course: ASEO02
The full FOV is twice the half-angle subtended by half the detector width: tan(θ/2) = (d/2)/f → FOV = 2·arctan(d/2f). For small angles FOV ≈ d/f. λ/d is a diffraction angle; d×f and f/d are dimensionally wrong.
Wrong options
FOV = λ / d
FOV = d × f
FOV = f / d
A2
What is the approximate relationship between ground sample distance (GSD), range R and instantaneous field of view (IFOV)?
TAHMİNİ
✅ GSD = R × IFOV
Evidence / source
Audio 13.23.00, 02:03–02:34
Course: ASEO02
With the small-angle approximation, a pixel's ground footprint = range × angular size: GSD = R × IFOV (IFOV in radians). Example: 120 µrad × 6000 m = 0.72 m. Range 2× → GSD 2×.
Wrong options
GSD = R / IFOV
GSD = IFOV / R
GSD = f-number × wavelength
A3
Which atmospheric processes redirect or remove radiation from the sensor path?
TAHMİNİ
✅ Scattering redirects it; absorption converts it into internal molecular energy
Evidence / source
Audio 13.23.00, 00:07–00:23
Course: ASEO04
Scattering does not destroy energy, it changes its direction. Absorption converts the energy into internal molecular energy (heat) and removes it from the beam. Together they form the extinction coefficient: γ = scattering + absorption, τ = e−γR.
Wrong options
Refraction destroys photons; reflection creates energy
Emission removes energy without any interaction
Diffraction absorbs all wavelengths equally
A6
According to the Stefan–Boltzmann law, what happens to total emitted power per unit area as temperature increases?
TAHMİNİ
✅ It increases in proportion to T⁴
Evidence / source
Audio 13.23.00, 00:48–01:06
Course: ASEO01
For a blackbody the radiant exitance is M = σT⁴ (εσT⁴ for a real surface). If T doubles, power rises 2⁴ = 16 times. Total area under the curve = S-B; the peak = Wien.
Wrong options
It decreases as 1/T
It increases linearly with T
It depends only on wavelength
A10
What causes chromatic aberration?
TAHMİNİ
✅ Refractive index varies with wavelength, so colours focus at different positions
Evidence / source
Audio 13.23.00, 02:22–02:31
Course: ASEO02
Dispersion: the refractive index n(λ) depends on wavelength → colours bend by different amounts and focus at different points on the axis. Fix: achromatic lens or reflective optics.
Wrong options
All wavelengths diffract identically
The aperture stop blocks off-axis rays
Detector pixels have unequal gain
A11
Which visible wavelengths are generally refracted most strongly by ordinary glass?
TAHMİNİ
✅ Shorter blue/violet wavelengths
Evidence / source
Audio 13.23.00, 02:22–02:31
Course: ASEO02
With normal dispersion n is larger at short wavelengths → blue/violet bends most and focuses closest to the lens. Red bends least and focuses farthest.
Wrong options
Only green at 555 nm
Longer red wavelengths
All visible wavelengths equally
A13
Which combination best describes increasing the f-number?
TAHMİNİ
✅ Less collected light, larger depth of field, and eventually more diffraction blur
Evidence / source
Audio 13.23.00, 02:32–02:42
Course: ASEO02
Increasing the f-number (stopping down): the aperture shrinks → light ∝ 1/(f/#)² drops, depth of field increases, and at very small apertures the Airy disk (r = 1.22λf/D) grows, so diffraction blur increases.
Wrong options
No change to exposure or aperture
More light and shallower depth of field
More light with no resolution effect
A19
Which statement correctly compares CCD and CMOS readout?
TAHMİNİ
✅ CCD transfers charge pixel-to-pixel to an output; CMOS normally uses per-pixel active readout
Evidence / source
Audio 13.23.00, 04:06–04:19
Course: ASEO03
The instructor said there will be a question on how CCD and CMOS work differently. CCD: charge is shifted across the chip → single/shared output → low noise, high uniformity. CMOS: amplifier in every pixel → fast, low power. The trap option swaps them. Both are staring arrays.
Wrong options
Both require mechanical scanning
CMOS transfers all charge through a single output and CCD uses per-pixel amplifiers
Neither is a staring array
A23
Which sequence correctly describes an image-intensifier NVG?
The instructor emphasized: an NVG starts and ends with photons, using electrons in between. Photocathode (photon→e⁻) → MCP (e⁻ multiplication) → phosphor (e⁻→photon) → eyepiece.
Wrong options
Photons → sound → electrons
Thermal photons → laser → CCD only
Electrons → photons → thermal heating → radio signal
A26
Which list best represents the essential stages of laser action?
TAHMİNİ
✅ Pumping, population inversion, stimulated emission, resonator feedback, output coupling
Evidence / source
Audio 13.23.00, 05:32–05:38
Course: ASEO05
The instructor advised reviewing the phases/stages of a laser. Pumping (add energy) → population inversion (more atoms up) → stimulated emission (identical photon) → resonator feedback (amplification between mirrors) → output coupling (partial mirror). The other options are terms from other topics.
Wrong options
Absorption, scattering, refraction, display
Detection, recognition, identification only
NUC, sampling, blooming, phosphor
A27
Why is population inversion necessary for laser amplification?
TAHMİNİ
✅ Stimulated emission must exceed absorption
Evidence / source
Audio 13.23.00, 05:32–05:38
Course: ASEO05
A photon can cause either stimulated emission or absorption. For net gain the upper level must be more populated than the lower → stimulated emission exceeds absorption. Spontaneous emission is not eliminated; it provides the seed photons that start lasing.
Wrong options
All atoms must remain in the ground state
Spontaneous emission must be eliminated completely
The cavity must contain no photons
A28
According to the Johnson criteria, what distinguishes detection, recognition and identification?
TAHMİNİ
✅ Presence; target class; specific type/identity
Evidence / source
Audio 13.23.00, 05:43–05:51
Course: ASEO07
The instructor asked for a high-level understanding of the Johnson criteria. Detection: is something there? · Recognition: which class (tank/aircraft)? · Identification: exactly which type (SR22, T-72)?
Wrong options
Colour; range; speed
Search; tracking; laser firing
Temperature; pressure; humidity
A29
Which approximate Johnson detail requirements were taught for detection, recognition and identification?
TAHMİNİ
✅ About 1, 4 and 7 line pairs respectively
Evidence / source
Audio 13.23.00, 05:43–05:51
Course: ASEO07
Harder tasks need more resolvable cycles on the target: D = 1, R = 4, I = 7 line pairs (2 / 8 / 14 pixels). The reversed order (7-4-1) is a trap. Memory: 1-4-7.
Wrong options
Exactly 1 line pair for all tasks
About 7, 4 and 1 line pairs respectively
About 10, 20 and 30 line pairs
A35
Sensor A has lower MRTD, lower NETD, lower NEI, higher SITF and higher SNR than Sensor B. Which is the better choice, all else equal?
TAHMİNİ
✅ Sensor A
Evidence / source
Audio 13.23.00, 05:51–06:40
Course: ASEO07
The instructor explicitly said a sensor-selection question based on a set of values will appear. Rule: MRTD, NETD, NEI → low is good · SITF, SNR → high is good. Sensor A is on the good side for all five → Sensor A.
Wrong options
They must be identical
No performance comparison is possible from these metrics
Sensor B
A36
Rayleigh scattering dominates when particle size is:
TAHMİNİ
✅ Much smaller than wavelength
Evidence / source
Audio 13.23.00, 06:41–06:56
Course: ASEO04
The instructor's Rayleigh–Mie–Geometric “song”. Rayleigh: particle ≪ λ (N₂, O₂ molecules), intensity ∝ λ⁻⁴ → blue sky.
Wrong options
Much larger than wavelength
Independent of wavelength
Comparable to wavelength
A37
Mie scattering dominates when particle size is:
TAHMİNİ
✅ Comparable to wavelength
Evidence / source
Audio 13.23.00, 06:41–06:56
Course: ASEO04
Mie: particle ≈ λ → haze, smoke, aerosol. Weak wavelength dependence (λ⁻¹…λ⁻²) → whitish haze and loss of contrast.
Wrong options
Much smaller than wavelength
Much larger than wavelength
Exactly zero
A38
Geometric scattering dominates when particle size is:
TAHMİNİ
✅ Much larger than wavelength
Evidence / source
Audio 13.23.00, 06:41–06:56
Course: ASEO04
Geometric: particle ≫ λ → raindrops, cloud/fog droplets, snow. Treated with geometrical optics (refraction/reflection), independent of wavelength (non-selective) → white clouds.
Wrong options
Exactly equal to the detector pixel
Smaller than an air molecule
Much smaller than wavelength
A39
Which matching of scattering type and example is correct?
The three regimes are separated by particle size relative to wavelength: small → medium → large = molecules → aerosols/haze → raindrops/cloud droplets.
All matter above absolute zero has which radiative property?
TAHMİNİ
✅ It emits electromagnetic radiation
Evidence / source
Exam-prep note 1
Course: ASEO01
Because of the thermal motion of particles, every body above 0 K emits EM radiation. 273 K (0 °C) is not a special limit; radiation needs no medium and travels through vacuum. That is why an IR camera sees in the dark.
Wrong options
It emits radiation only above 273 K
It emits only if illuminated by the Sun
It cannot radiate in a vacuum
A42
Which sequence gives the commonly used EO/IR spectral bands in increasing wavelength?
Increasing wavelength: VIS → NIR → SWIR → MWIR → LWIR. Note: this source gives NIR 0.7–1.4 µm and LWIR 8–14 µm; other tables on the site use NIR 0.7–1.0 and LWIR 8–12 µm. Both are common definitions and the order is the same. The reversed order (LWIR→VIS) is decreasing wavelength.
Wrong options
All bands occupy the same wavelengths
LWIR; MWIR; SWIR; NIR; visible
Visible 3–5 µm; NIR 8–14 µm; MWIR 0.4–0.7 µm
A43
For a fixed detector size, what happens when focal length and optical magnification increase?
TAHMİNİ
✅ Field of view decreases
Evidence / source
Exam-prep note 3
Course: ASEO02
With a fixed detector FOV ≈ d/f → as f grows, FOV shrinks and magnification rises. Example: 50 → 200 mm = 4× magnification, FOV 4 times narrower. Long f = identification, short f = search.
Wrong options
Aperture diameter must become zero
Field of view remains constant
Field of view increases
A44
Under humid atmospheric conditions, which thermal band is generally most affected by water-vapour absorption among SWIR, MWIR and LWIR?
TAHMİNİ
✅ LWIR
Evidence / source
Exam-prep note 19
Course: ASEO04
According to the lecture slides, humidity/water-vapour absorption matters especially in the LWIR (MWIR is less sensitive to water vapour). Careful: if the question asked about scattering, the answer would be the short wave (SWIR). Absolute statements like “completely opaque” are wrong; real transmission depends on path and wavelength.
Wrong options
MWIR is always completely opaque
SWIR is always completely opaque
All three are affected identically
A45
Which statement correctly distinguishes absorption, spontaneous emission and stimulated emission in laser physics?
TAHMİNİ
✅ Absorption raises an atom; spontaneous emission is random; stimulated emission produces a matching photon
Evidence / source
Exam-prep note 20
Course: ASEO05
Absorption: a photon is absorbed and the atom moves up. Spontaneous: decays on its own (~10⁻⁸ s) with random direction/phase. Stimulated: an incoming photon produces a second photon with the same frequency, phase and direction; the incoming photon continues too → coherent amplification.
Wrong options
All three processes produce identical random photons
Stimulated emission destroys the incident photon without replacement
Absorption lowers an atom while spontaneous emission raises it
A46
Which matching of laser property and meaning is correct?
Monochromaticity – high divergence; coherence – many colours; directionality – random propagation
A47
According to the NVG distance-illusion rule of thumb, which relation is correct?
TAHMİNİ
✅ Dark night: real distance = perceived distance × 2; clear night: real distance = perceived distance / 2
Evidence / source
ASEO08 Tactical Advantages and Limitations, slide 23 · topic reported by the student
Course: ASEO08
Slide 23: dark night ×2, clear night ÷2. Example: perceived 300 m on a dark night → real 600 m; perceived 800 m on a clear night → real 400 m. The second option is the reversed trap.
Wrong options
Dark night: real distance = perceived distance / 2; clear night: real distance = perceived distance × 2
Real distance always equals perceived distance, regardless of night conditions
Real distance = perceived distance × 2 on both dark and clear nights
A49
Which radiation law states that the peak-emission wavelength is inversely proportional to absolute temperature (λmax × T = b)?
TAHMİNİ
✅ Wien's Displacement Law
Evidence / source
Instructor review of Stefan–Boltzmann & Wien · ASEO01 thermal radiation · colleague booklet Q5
Course: ASEO01
Wien: λmax × T = b (2898 µm·K) → as T rises the peak shifts to shorter wavelengths. Don't mix up: Stefan–Boltzmann = total power ∝ T⁴ · Beer–Lambert = atmospheric transmission e−γR · Snell = refraction n₁sinθ₁ = n₂sinθ₂.