ECEG 105 ECEU 646 Optics for Engineers Course

ECEG 105 & ECEU 646 Optics for Engineers Course Notes Part 11: Radiometry & Photometry Prof. Charles A. Di. Marzio Northeastern University Fall 2003 July 2003 Chuck Di. Marzio, Northeastern University 1

Radiometric Quantities July 2003 Chuck Di. Marzio, Northeastern University 2

Radiometry and Photometry Notes: Spectral x=dx/dn or dx/dl: Add subscript n or w, divide units by Hz or mm. 1 W is 683 L at 555 nm. F, Flux Radiant Flux E, Flux/Area Rcd. I, Flux/W Radiant Irradiance Watts/m 2 Illuminance Lumens/m 2 =Lux 1 Ft Candle=1 L/ft 2 July 2003 Watts Luminous Flux Lumens Intensity Watts/sr Luminous Intensity Lumens/sr 1 Candela=1 cd=1 L/sr Chuck Di. Marzio, Northeastern University M, Flux/Proj. Area Radiant Exitance Watts/m 2 Luminous Flux Lumens/m 2=Lux L, Flux/AW Radiance 2 Watts/m /sr Luminance Lumens/m 2/sr 1 Lambert= (1 L/cm 2/sr)/p 1 ft. Lambert= (1 L/ft 2/sr)/p 1 m. Lambert= (1 L/m 2/sr)/p 3

The Radiance Theorem n 2 n 1 d. W 2 d. A q 2 q 1 d. W 1 July 2003 Chuck Di. Marzio, Northeastern University 4

Radiance in Images d. A 2 d. A’ d. A 1 d. W 2 d. W 1 z July 2003 Chuck Di. Marzio, Northeastern University 5

Resonant Cavity Modes July 2003 Chuck Di. Marzio, Northeastern University 6

Resonant Frequencies in Cavity ny nx nz July 2003 Chuck Di. Marzio, Northeastern University 7

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

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

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

Total Spectral Energy July 2003 Chuck Di. Marzio, Northeastern University 11

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

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

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

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

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

2 /m m Ml, Spectral Radiant Exitance, W/m Black Body Equations (2) July 2003 10 10 10 5 10 0 10 -5 10 -10 10000 5000 2000 10 500 1000 -1 T=300 k 0 1 10 10 l , Wavelength, m m Chuck Di. Marzio, Northeastern University 10 2 17

Solar Irradiance on Earth Data from The Science of Color, Crowell, 1953 3000 Exoatmospheric Sea Level filename=m 1695. m 5000 K Black Body Normalized to 1000 W/m 2 2500 E , Spectral Irradiance, W/m 2/ mm l 6000 K Black Body Normalized to 1560 W/m 2 2000 1500 1000 500 0 July 2003 0 200 400 600 800 1000 1200 1400 1600 l, Wavelength, nm Chuck Di. Marzio, Northeastern University 1800 2000 18

Typical Outdoor Radiance Levels Ultraviolet Visible Near IR Mid IR Far IR 6000 K Sun 6. 9 G Lux Sunlit Cloud 6. 9 k Lux Blue Sky 300 K night sky Atmospheric Passbands July 2003 Chuck Di. Marzio, Northeastern University 19

D Ml/Delta T Thermal Imaging T = 300 K 1 0. 5 0 1 10 T = 500 K 10 10 2 D Ml/Delta T 0 -1 10 6 4 2 0 -1 10 July 2003 10 10 l, Wavelength, m m Chuck Di. Marzio, Northeastern University 20

Luminance and Radiance Photopic Sensitivity 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 0 400 500 600 700 800 Wavelength, nm July 2003 Chuck Di. Marzio, Northeastern University 21

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

Lighting Efficiency Light Output, Lumens 1000000 Fluorescent 94 Lumens/Watt at 7000 K (Highest Efficiency Body) 683 Black Lumens/Watt 100000 Hi Pressure Na Metal Halide Lo Pressure Na Incandescent for Green Light 10000 1000 20. 7 Lumens/Watt at 3000 K 100 1 July 2003 10 1000 Chuck Di. Marzio, Northeastern University Power Input, Watts Thanks to John Hilliar (NU MS ECE 1999) for finding lighting data from Joseph F. Hetherington at www. hetherington. com. 10 June 1998 10000 23

Emissivity July 2003 Chuck Di. Marzio, Northeastern University 24

Color: Tristimulus Values July 2003 1. 8 Tristimulus Value • Describe Eye’s Response to Color • Based on Color Matching Experiments • Small Number of Observers • Lines are Approximations 2 z 1. 6 y 1. 4 1. 2 x 1 0. 8 0. 6 0. 4 0. 2 0 300 350 400 450 500 550 600 650 700 750 800 Wavelength, nm Chuck Di. Marzio, Northeastern University 25

Tristimulus Value Characterizing Colors Object z Spectrum y x 1. 8 1 0 400 500 600 700 y 800 Wavelength, nm July 2003 Chuck Di. Marzio, Northeastern University x 26

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

/m m 250 M l , Spectral Radiant Exitance, W/m 300 2 Optical Properties of Polar Bears From Sun To Sky Net 200 150 HP Filter Reflects 100 50 0 HP Filter Passes -50 -1 10 July 2003 0 1 10 10 l , Wavelength, m m Chuck Di. Marzio, Northeastern University 10 2 28

Changing Incident Irradiance Net Irradiance 1500 Perfect Bare Bear 400 nm Hi. Pass 800 nm Hi. Pass 2. 5 m m Hi. Pass Best Bear 1000 500 0 -500 0 500 1000 1500 Incident Irradiance July 2003 Chuck Di. Marzio, Northeastern University 29