Contraharmonic Mean Filter
Command
Image
Filters
Contraharmonic Mean Filter
Description
Applies a contraharmonic mean filter to an image.
With a contraharmonic mean filter, the color value of each pixel is replaced with the contraharmonic mean of color values of the pixels in a surrounding region.
The contraharmonic mean with order Q is defined as:
A contraharmonic mean filter reduces or virtually eliminates the effects of salt-and-pepper noise. For positive values of Q, the filter eliminates pepper noise. For negative values of Q it eliminates salt noise. It cannot do both simultaneously.
Note that the contraharmonic filter is simply the arithmetic mean filter if Q = 0, and the harmonic mean filter if Q = −1.
A larger region (filter size) yields a stronger filter effect with the drawback of some blurring.
Dialog box
Filter Size: larger filter yields stronger effect.
Order: the order Q of the filter.
Click Preview to judge the results.
Click OK to proceed.
Examples
| Before: | After (Q=1): | After (Q=-1): | ||
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