Dilation and ROIs

Posted by Jeremy Adler on May 09, 2014; 7:52am
URL: http://imagej.273.s1.nabble.com/Dilation-and-ROIs-tp5007649.html

I have a slightly surprising result when dilating within a ROI.
My expectation was that any processing within the ROI would not extend outside the ROI and that pixels outside the ROI would have no influence on the processing within the ROI.

1) The dilation of pixels) within the ROI (outside starts empty) stays within the ROI, which is fine, except when the edge of the ROI is one pixel away from the edge of the window, when the dilation extends and sets pixels outside the ROI, those on the right and bottom, but oddly not the top or left.

2) Pixels in the ROI are affected by pixels outside the ROI - a pixel just outside the ROI causes the adjacent pixel in the ROI to be dilated.

3) Non Binary, Pixels outside the ROI also affect pixels inside the ROI - seen with Process/Filters/Mean








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