03/18/2003
15-462 Graphics I
16
Point Processing
•Input:
a(x,y); Output: b(x,y) = f(a(x,y))
•Useful
for contrast adjustment, false colors
•Examples
for grayscale, 0 · v · 1
–f(v) =
v (identity)
–f(v) =
1-v (negate image)
–f(v) =
vp,
p < 1 (brighten)
–f(v) =
vp,
p > 1 (darken)
•Gamma
correction compensates
monitor brightness loss
v
f(v)