MATLAB: How to plot an intensity profile within given pix depth

Question

Hi guys,

Would someone please help me to do the following thing: I have an image of a roughly elliptical object. I know the outline coordinates of it. I would like to:

1. Plot as a heat-map only pixels of this object that are 10 pixels or so from the object outline inward.
2. Average the intensities of these 10 pixels at every position and plot this as a heat-map.
3. Plot #2 on a perimeter of a circle starting from the default position.

The idea is to make an intensity profile within the given depth from the object outline (#1 and #2) and to find the angular distribution of intensities; on X axis angle, on Y axis pix intensities.

Thanks in advance, jakub

Answer 1

You can the the pixels 10 out from your boundary by getting a binary image from your coordinates first using poly2mask. Then use imdilate to grow that blob out by 10 pixels. Then use bwperim() to get the new boundary locations' pixel values (Untested)

binaryImage = poly2mask(x, y, rows, columns);
SE = strel('disk', R, N)
biggerBlob = imdilate(binaryImage, SE);
perimPixels = bwperim(biggerBlob)
meanGL = mean(grayImage(perimPixels));