Mean filtering
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
90
0
0
0
0
0
0
0
0
0
0
0
0
0
0
90
90
90
90
90
0
0
0
0
0
90
90
90
0
90
0
0
0
0
0
90
90
90
90
90
0
0
0
0
0
90
90
90
90
90
0
0
0
0
0
90
90
90
90
90
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
10
10
10
10
20
30
30
30
30
20
10
20
40
60
50
50
30
20
0
30
60
90
80
80
50
30
0
30
60
90
80
80
50
30
0
30
60
90
90
90
60
30
0
20
40
60
60
60
40
20
0
10
20
30
30
30
20
10
0
Replace each pixel with an average of the pixels in the k
´
k box around it
•
3
´
3 case: