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| File Edit Options Process Analyze Video Macros Stacks SEM SPM Windows Help |
Sharpen Shadow Find Edges Rank Filters Dither Convolve PlugIn Filters
Enhance Contrast Equalize Fix Colors Differential Curvature Unsharp Mask Hough Transform |
These filters,
with the exception of Reduce Noise and Dither,
are implemented using 3 x 3 spatial convolutions, where the value of
each pixel in the selection is replaced with the weighted average of
its 3 x 3 neighborhood. They are not limited to rectangular selections.
The entire image is filtered if no selection is active. They do not
work correctly with 8-bit true color images. They can be aborted by
typing command-period. The 3 x 3 tables shown below are the
coefficients (weighting factors) for the filters.
Sharpen increases contrast and accentuates detail in the selection, but may also accentuate noise. To minimize this problem, you can Smooth and/or Reduce Noise before using Sharpen. Hold the option key down for increased sharpening.
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Steve Barrett November 2014 |
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