ECE 449CS 443: COMPUTER VISON LECTURE 5

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ECE 449/CS 443 COMPUTER VISON LECTURE 5

• Radiometry
• Image Formation
• Surface and Image Brightness
• Radiance and Irradiance
• Radiometry of Thin Lenses
• Reading
• Radiometry (Chapter 1)
• For next time Sources, shadows and shading
  (Chapter 3)

• Homework Exercises 2.4 and 2.5, due Thursday.

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Image Formation Radiometry
The light source(s)
The sensor characteristics
The surface normal
The surface properties
The optics
What determines the brightness of an image pixel?
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DEFINITION The radiance is the power traveling
at some point in a given direction per unit area
perpendicular to this direction, per unit solid
angle.
d2P L( P, v ) dA dw
d2P L( P, v ) cosq dA dw
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DEFINITION Angles and Solid Angles
(radians)
(steradians)
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DEFINITION Irradiance
The irradiance is the power per unit area
incident on a surface.
d2PdE dALi( P , vi ) cosqidwi dA
dE Li( P , vi ) cosqi dwi
EsH Li (P, vi) cosqi dwi
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Photometry

• L is the radiance.
• E is the irradiance.