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

Radiometric Quantities July 2003 Chuck DiMarzio, Northeastern University

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

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

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

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

Resonant Frequencies in Cavity ny nx nz July 2003 Chuck DiMarzio, Northeastern University

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Chuck DiMarzio, Northeastern University Lighting Efficiency 1000000 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 www.hetherington.com. 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

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

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

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

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

Optical Properties of Polar Bears 10 -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

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