1. Computer Graphics (Spring 2003)
COMS 4160, Lecture 4: Review session
Ravi Ramamoorthi

2. Gamma Correction
A scene is photographed with camera gamma = .5 and displayed on a CRT with gamma 2.4 If we want the system gamma to be 1, what gamma correction need we apply?
What does failure to gamma correct do to the saturation of colors? That is, if I have a color like (1.0, 0.5, 0.5) which is a fairly desaturated red, will failure to gamma-correct make it appear more reddish (greenish?, bluish?). How does this effect vary with how saturated the color is originally? Justify your answer quantitatively.

3. Intensity and Color
You have a 300 dpi bilevel printer, and need an effective resolution of 75 dpi. How many effective shades of gray can you obtain by halftoning?
Write down R, G, B values as appropriate weighted summations or integrals over the illumination spectrum. Can two different spectral distributions of light have the same visual sensation or RGB values?

4. Scan conversion
Give a general incremental algorithm for scan converting a polynomial function of the form y = f(x) [assume slope < 1]. How does this relate to computing derivatives?