How to calculate the area of dark core of intensity distribution at Full width at half maximum?, which has ring like structure.

Hello sir,

I have to calculate the area of dark core of intensity distribution at Full width at half maximum, which has ring like structure.

Can anyone help in this reard

Thanking you sir

[MOHD]

I required number of total dark pixels in dark core

Answer 1

[Image Analyst]

Try this:

fileName = 'XYintensity.png';
grayImage = imread(fileName);
subplot(2, 1, 1);
imshow(grayImage);
axis('on', 'image');
drawnow;
threshold = mean([min(grayImage(:)), max(grayImage(:))])
mask = grayImage < threshold;
% Get rid of surround
mask = imclearborder(mask);
% Take biggest blob
mask = bwareafilt(mask, 1);
subplot(2, 1, 2);
imshow(mask);
axis('on', 'image');
% Get the area
area = bwarea(mask)

[MOHD]

Sir, Thank you very much for your answere.

Is area is giving count of dark pixels? It is number but I am getting real number, is it correct?

[Image Analyst]

It's the aread of the mask using the formula from bwarea(), which is not a pixel count but takes into account the shape of the boundary. If you want a pixel count, you can sum the mask

areaInPixels = sum(mask(:));

[MOHD]

Sir, Thank you very much for your answere. How we can apply this for to find dark core area at full width?

[Image Analyst]

I'm not sure what area you want but you can adjust the threshold from the "half maximum" intensity value you first requested to some other value (higher or lower) to control how much of the fuzzy donut hole it takes. Since it's not a step, but a sloped intensity, where you say the edge actually is, is a judgment call.

[MOHD]

Sir, Thank you very much. I mean, how to find the dark core area at edge?