Theory of Color Image Formation

Let Nobj be the normal vector at the position where an incoming ray hits the object. Let Ni be a normalized vector that points to the direction of the light source. Let p be the angle between the normal vector Nobj and the vector N that points to the fight source. Then the angle between the outgoing ray and the normal vector will also be p. For a transparent object, part of the ray will be refracted and the remainder will be reflected. 

Color Constancy M. Ebner 2007 John Wiley Sons, Ltd 

Eventually, the ray of light will enter the lens of the camera. In the back of the camera, we either have an analog film or a sensor array that measures the incident light. We will look at how the analog film responds to light in the next section. Digital photography is addressed in Section 3.2. 

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From the theory of color image formation, we have seen that the intensity /, f.v. y) measured by a sensor i with i e r, g, b at position (x, y) on the sensor array can be approximated by... 

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