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CImCombine:RankClip
The RankClip method merges the pixel values after clipping outliers in the upper and lower rank percentiles of the distribution at each point.
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CImage = CImCombine:RankClip( CImageSet, pHigh=2.5, pLow=2.5 ) |
CImageSet contains the collection of images to be
combined.
pHigh is the upper rank percentile for rejecting
points, e.g., pHigh = 2 rejects points
in the upper 2 percentile of the distribution—that is, points at or
above the 98th percentile.
pLow is the lower rank percentile for rejecting
points, e.g., plow = 2 rejects points
in the lower 2 percentile of the distribution.
CImage is a new image created by this method.
On success,
this method returns a new CImage.
On failure,
this method returns nil.
Each pixel in the output image is the mean value of all images after rejection of images having values inside the upper nHigh percentile and images having pixels in the lower nLow percentile of values at each location.
Suppose a CImageSet named S exists. The following script fragment combines the images by the RankClip method by excluding points above the 95th percentile and below the 2nd percentile. The images are normalized by the Median statistic computed inside the central 10% of the image:
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C = CImCombine:new() |
-- create a CImCombine object |
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R = CRect:new(10,50,10,50) |
-- central 10% of the image |
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C:SetRelRect( R ) |
-- specify CImage and CRect to measure |
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C:SetNormStat("median") |
-- use the RankClip as the normalization statistic |
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C:SetNormMethod("scale") |
-- scale to normalize the image set |
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I = C:RankClip( S, 5, 2 ) |
-- combine the image set and return a new image |
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I:Display() |
-- show the new image |
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C:delete() |
-- when done with S, remove it from memory |