Image Processing Reference
In-Depth Information
Figure 6.1
Median filter and fine detail. Two examples of image detail that may be damaged
by median filtering. The first shows that a corner pixel will be removed from a 90-degree an-
gle. This may be preserved using a weighted median filter. The second effect is known as
edge “pulling”. Isolated noise pixels close to an edge can cause it to be pulled out at this
point.
6.5 Optimum Design of Weighted Rank and Median Filters
Where certain fine structures must be preserved within an image, the filter weight-
ing can be chosen to do this. For example, consider the case of corner preservation
in median filtering. Consider the foreground pixel to have value 1 and the back-
ground 0.
