Jan 2004 Chuck DiMarzio, Northeastern University ECEG287 Optical Detection Course Notes Part 2: Radiometry Profs. Charles A. DiMarzio and Stephen W. McKnight Northeastern University, Spring 2004

Jan 2004 Chuck DiMarzio, Northeastern University Topic Outline Radiometric Quantities and Units Radiance Theorem Black-Body Spectrum Some Radiance/Irradiance Values A Little about Color

Jan 2004 Chuck DiMarzio, Northeastern University Radiometric Quantities

Jan 2004 Chuck DiMarzio, Northeastern University Radiometry and Photometry , Flux M, Flux/Proj. Area I, Flux/  L,Flux/A  E, Flux/Area Rcd. Radiant Flux Watts Luminous Flux Lumens Radiant Exitance Watts/m 2 Luminous Flux Lumens/m 2 =Lux Radiance Watts/m 2 /sr Luminance Lumens/m 2 /sr 1 Lambert= (1L/cm 2 /sr)/  1 ftLambert= (1L/ft 2 /sr)/  1mLambert= (1L/m 2 /sr)/  Radiant Intensity Watts/sr Luminous Intensity Lumens/sr 1 Candela=1cd=1L/sr Irradiance Watts/m 2 Illuminance Lumens/m 2 =Lux 1 Ft Candle=1L/ft 2 Notes: Spectral x=dx/d or dx/d : Add subscript or , divide units by Hz or  m. 1 W is 683 L at 555 nm.

Jan 2004 Chuck DiMarzio, Northeastern University The Radiance Theorem 11 22 n1n1 n2n2 dA d1d1 d2d2

Jan 2004 Chuck DiMarzio, Northeastern University Radiance in Images dA’ d1d1 d2d2 dA 1 dA 2 z

Jan 2004 Chuck DiMarzio, Northeastern University Resonant Cavity Modes

Jan 2004 Chuck DiMarzio, Northeastern University Resonant Frequencies in Cavity nxnx nznz nyny

Jan 2004 Chuck DiMarzio, Northeastern University Counting the Modes nxnx nznz nyny

Jan 2004 Chuck DiMarzio, Northeastern University Energy per Mode (1)

Jan 2004 Chuck DiMarzio, Northeastern University Energy per Mode (3)

Jan 2004 Chuck DiMarzio, Northeastern University Total Spectral Energy

Jan 2004 Chuck DiMarzio, Northeastern University Black Body Radiance (1) A A’

Jan 2004 Chuck DiMarzio, Northeastern University Black Body Radiance (2) A A’

Jan 2004 Chuck DiMarzio, Northeastern University Spectral Radiant Exitance (1) x y z   dd dd

Jan 2004 Chuck DiMarzio, Northeastern University Spectral Radiant Exitance (2)

Jan 2004 Chuck DiMarzio, Northeastern University Black-Body Equation (1)

Jan 2004 Chuck DiMarzio, Northeastern University Black Body Equations (2) T=300k

Jan 2004 Chuck DiMarzio, Northeastern University Solar Irradiance on Earth Data from The Science of Color, Crowell, 1953, Wavelength, nm E, Spectral Irradiance, W/m 2 /  m Exoatmospheric filename=m1695.m Sea Level 5000 K Black Body Normalized to 1000 W/m K Black Body Normalized to 1560 W/m 2

Jan 2004 Chuck DiMarzio, Northeastern University Typical Outdoor Radiance Levels Visible Near IR Mid IR Far IR Atmospheric Passbands Ultraviolet

Jan 2004 Chuck DiMarzio, Northeastern University Thermal Imaging  M /Delta T T = 300 K , Wavelength,  m  M /Delta T T = 500 K

Jan 2004 Chuck DiMarzio, Northeastern University Luminance and Radiance Wavelength, nm Photopic Sensitivity y This curve shows the relative sensitivity of the eye. To convert to photometric units from radiometric, multiply by 683 Lumens Per Watt

Jan 2004 Chuck DiMarzio, Northeastern University Some Typical Luminance And Radiance Levels

Jan 2004 Chuck DiMarzio, Northeastern University Emissivity

Jan 2004 Chuck DiMarzio, Northeastern University Color: Tristimulus Values Wavelength, nm Tristimulus Value Describe Eye’s Response to Color Based on Color Matching Experiments Small Number of Observers Lines are Approximations z y x

Jan 2004 Chuck DiMarzio, Northeastern University Characterizing Colors Wavelength, nm Tristimulus Value z x y Object Spectrum x y

Jan 2004 Chuck DiMarzio, Northeastern University Recording and Generating Color Images Camera with Three Filters Display with Three Sources Eye Object Three Separate Registered Images