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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
rank (sort) the nine pixels in each 3 x 3 neighborhood and replace the
center pixel with the median, minimum (lightest), or maximum (darkest)
value. Use the Median filter to reduces noise. The Minimum filter
erodes (shrinks) objects in grayscale images similar to the way binary erosion shrinks objects in binary images.
The Maximum filter dilates (expands) objects in grayscale images
similar to the way binary dilation
expands objects in binary images.
Median (Reduce Noise) Each pixel will
be replaced with the median value in its 3 x 3 neighborhood. This is a
time consuming operation because, for each pixel in the selection, the
nine pixels in the 3 x 3 neighborhood must be sorted and the center
pixel replaced with the median (fifth) value.
Minimum (Erode) Each pixel is
replaced with the minimum value in the 3 x 3 neighborhood. With binary
images, this produces the same result as the Erode filter with count set to one.
Maximum (Dilate) Each pixel is
replaced with the maximum value in the 3 x 3 neighborhood. With binary
images, this produces the same result as the Dilate filter with count set to
one.
Opening Closing |
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Steve Barrett November 2014 |
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