How to find area of specific region in binary image ?
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For example, I have image with
- region1 white,
- region2 black,
- region3 white,
- region4 black and
- region5 white.
How can I know pixel density in region4 and how to convert that specific area mm2/cm2 ?
2 Comments
Image Analyst
on 29 Nov 2020
What do you mean by pixel density? All regions of the image have the same density (pixels per unit area). Or do you mean "optical density", in other words, intensity of a gray scale image in region 4?
Answers (1)
Image Analyst
on 30 Nov 2020
Edited: Image Analyst
on 30 Nov 2020
See my Image Segmentation Tutorial in my File Exchange:
In short, segment your image by thresholding or whatever to get a mask, then do
props = regionprops(mask, grayImage, 'Area', 'MeanIntensity');
for k = 1 : numel(props)
fprintf('Blob #%d has an area of %d pixels (%.2f sq. cm), and mean intensity of %.2f\n', ...
k, props(k).Area, props(k).Area * cmPerPixel^2, props(k).MeanIntensity);
end
To see how to determine the number of pixels per cm, see my attached spatial calibration demo.
6 Comments
Image Analyst
on 1 Dec 2020
areaOfBlob3 = allAreas(3);
I think that's SO obvious that I'm not sure it's what you mean, so try to explain better.
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