Common laws of photometric measurement

1, the intensity of illumination of the inverse square law of

define vertical light intensity of illumination in the direction of propagation is proportional to the light source in the direction of light intensity, and the light source is inversely proportional to the square of the distance of the surface.

note only conform to the point light source distance inverse square law. ( Test lamps and lanterns should not be less than the distance light mouth maximum size 10 times. )

2, intensity of illumination of cosine law

3, cosine law of cubic

in type I - Point light intensity at that point;

　　　　　h— The height of the light source from the plane;

　　　　　θ— Surface normals and the Angle of incident light;

　　　　　— Length of OA.

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