1. Please describe three principle ways to estimate a degradation function.

2. Please calculate the new intensity of the center pixel of the 3*3 region below using 3*3 midpoint filter and 3*3 geometric mean filter.

20 25 21

22 12 18

18 19 20

3. A 3*3 average filter is applied to the 3*3 color subimage below. What is the new color (RGB) of the center pixel? Red

220 121 214

86 79 118

185 153 120

Green

120 21 72

92 53 78

13 25 12

Blue

176 215 100

24 47 39

162 99 166

4. Please convert cyan color (0, 255, 255) from RGB model to HIS model.