1. ECEG105 & ECEU646 Optics for Engineers Course Notes Part 11: Radiometry & Photometry
Prof. Charles A. DiMarzio
Northeastern University
Fall 2003
July 2003
Chuck DiMarzio, Northeastern University

2. Radiometric Quantities
July 2003
Chuck DiMarzio, Northeastern University

3. Radiometry and Photometry
Notes: Spectral x=dx/dn or dx/dl: Add subscript n or w, divide units by Hz or mm.
M, Flux/Proj. Area
F, Flux
Radiant Flux
Watts
Luminous Flux
Lumens
Radiant Exitance
Watts/m2
Luminous Flux
Lumens/m2=Lux
1 W is 683 L at 555 nm.
I, Flux/W
Radiant Intensity
Watts/sr
Luminous Intensity
Lumens/sr
L,Flux/AW
Radiance
Watts/m2/sr
Luminance
Lumens/m2/sr
1 Lambert=
(1L/cm2/sr)/p
E, Flux/Area Rcd.
Irradiance
Watts/m2
Illuminance
Lumens/m2=Lux
1 ftLambert= (1L/ft2/sr)/p
1mLambert= (1L/m2/sr)/p
1 Ft Candle=1L/ft2
1 Candela=1cd=1L/sr
July 2003
Chuck DiMarzio, Northeastern University

4. Chuck DiMarzio, Northeastern University
The Radiance Theorem n1 n2
dW2 dA q2 q1
dW1
July 2003
Chuck DiMarzio, Northeastern University

5. Chuck DiMarzio, Northeastern University
Radiance in Images
dA2
dA’
dA1
dW2
dW1 z
July 2003
Chuck DiMarzio, Northeastern University

6. Chuck DiMarzio, Northeastern University
Resonant Cavity Modes
July 2003
Chuck DiMarzio, Northeastern University

7. Resonant Frequencies in Cavityny nx nz
July 2003
Chuck DiMarzio, Northeastern University

8. Chuck DiMarzio, Northeastern University
Counting the Modes ny nx nz
July 2003
Chuck DiMarzio, Northeastern University

9. Chuck DiMarzio, Northeastern University
Energy per Mode (1)
July 2003
Chuck DiMarzio, Northeastern University

10. Chuck DiMarzio, Northeastern University
Energy per Mode (3)
July 2003
Chuck DiMarzio, Northeastern University

11. Chuck DiMarzio, Northeastern University
Total Spectral Energy
July 2003
Chuck DiMarzio, Northeastern University

12. Chuck DiMarzio, Northeastern University
Black Body Radiance (1) A’ A
July 2003
Chuck DiMarzio, Northeastern University

13. Chuck DiMarzio, Northeastern University
Black Body Radiance (2) A’ A
July 2003
Chuck DiMarzio, Northeastern University

14. Spectral Radiant Exitance (1)z dq q y df f x
July 2003
Chuck DiMarzio, Northeastern University

15. Spectral Radiant Exitance (2)
July 2003
Chuck DiMarzio, Northeastern University

16. Black-Body Equation (1)
July 2003
Chuck DiMarzio, Northeastern University

17. Black Body Equations (2)10 -1 1 2
-10 -5 5 l
, Wavelength, m M
, Spectral Radiant Exitance, W/m /
10000
5000
2000
500
1000
T=300k
July 2003
Chuck DiMarzio, Northeastern University

18. Solar Irradiance on Earth
Data from The Science of Color, Crowell, 1953
3000
Exoatmospheric filename=m1695.m
Sea Level
5000 K Black Body Normalized to 1000 W/m 2
2500
6000 K Black Body Normalized to 1560 W/m 2 m m / 2
2000
, Spectral Irradiance, W/m
1500
1000 l E
500
200
400
600
800
1000
1200
1400
1600
1800
2000 l
, Wavelength, nm
July 2003
Chuck DiMarzio, Northeastern University

19. Typical Outdoor Radiance Levels
Ultraviolet
6000K Sun
6.9 G Lux
Sunlit
Cloud
6.9 k Lux
Blue
Sky
300K
night sky
Visible
Near IR
Mid IR
Far IR
Atmospheric Passbands
July 2003
Chuck DiMarzio, Northeastern University

20. Chuck DiMarzio, Northeastern University
Thermal Imaging D M
/Delta T 10 -1 1 2
0.5 l
T = 300 K 4 6
, Wavelength, m
T = 500 K
July 2003
Chuck DiMarzio, Northeastern University

21. Luminance and Radiance
1.8
This curve shows the relative sensitivity of the eye. To convert to photometric units from radiometric, multiply by 683 Lumens Per Watt y 1
Photopic Sensitivity
400
500
600
700
800
Wavelength, nm
July 2003
Chuck DiMarzio, Northeastern University

22. Some Typical Luminance And Radiance Levels
July 2003
Chuck DiMarzio, Northeastern University

23. Chuck DiMarzio, Northeastern University
Lighting Efficiency
Fluorescent
94 Lumens/Watt at 7000K
(Highest Efficiency
Black Body)
Hi Pressure Na
Metal Halide
100000
683 Lumens/Watt
for Green Light
Lo Pressure Na
Incandescent
Light Output, Lumens
10000
Thanks to John Hilliar (NU MS ECE 1999) for finding lighting data from Joseph F. Hetherington at 10 June 1998
1000
20.7 Lumens/Watt at 3000K
100 1 10
100
1000
10000
July 2003
Chuck DiMarzio, Northeastern University
Power Input, Watts

24. Chuck DiMarzio, Northeastern University
Emissivity
July 2003
Chuck DiMarzio, Northeastern University

25. Color: Tristimulus Values
Describe Eye’s Response to Color
Based on Color Matching Experiments
Small Number of Observers
Lines are Approximations 2
1.8 z
1.6 y
1.4 x
1.2
Tristimulus Value 1
0.8
0.6
0.4
0.2
300
350
400
450
500
550
600
650
700
750
800
Wavelength, nm
July 2003
Chuck DiMarzio, Northeastern University

26. Characterizing Colors
Object
Spectrum
400
500
600
700
800 1
1.8
Wavelength, nm
Tristimulus Value z x y y x
July 2003
Chuck DiMarzio, Northeastern University

27. Recording and Generating Color Images
Three Separate
Registered Images
Object
Camera
with
Three
Filters
Display
with
Three
Sources
Eye
July 2003
Chuck DiMarzio, Northeastern University

28. Optical Properties of Polar Bears10 -1 1 2
-50 50
100
150
200
250
300 l
, Wavelength, m M
, Spectral Radiant Exitance, W/m /
From Sun
To Sky
Net HP
Filter Reflects
HP Filter Passes
July 2003
Chuck DiMarzio, Northeastern University

29. Changing Incident Irradiance
Net Irradiance
1500
Perfect
Bare Bear
400nm HiPass
1000
800nm HiPass
2.5 m
m HiPass
Best Bear
500
-500
500
1000
1500
Incident Irradiance
July 2003
Chuck DiMarzio, Northeastern University