MATLAB: Finding a closed region

closed regionimage processingpolygon

i want to find closed regions, whose intensity values are all 255, in an image matrix. is there a function to do it directly or is there another way?

thanks

Best Answer

Create a mask of your regions (blobs). Then use the fourth syntax of REGIONPROPS to specify both the mask and the intensity image. With that syntax, you can calculate the 'PixelValues' of each blob, and use whatever test you want to classify them.

Alternatively, for this simple case, you can request 'MinIntensity' and 'MaxIntensity' properties of the blobs. Then, if min==255 AND max==255, all pixels in the region must be 255.

Cheers,

Brett

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Try this:

mask = grayImage >= 165 & grayImage <= 166 % Mask of only pixels with GLs of 165 and 166
grayImage(~mask) = 0; % blacken outside the mask.

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Try something like this

% grayImage = imread('cameraman.tif');
someThreshold = 190;
binaryImage = grayImage < someThreshold;
labeledImage = bwlabel(binaryImage);
measurements = regionprops(labeledImage, grayImage, 'MaxIntensity');
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That gives a blob-by-blob accounting of the max. If you just want the max of the image above and below the threshold, you can simply do this

mask = grayImage < someThreshold;
maxAbove = max(grayImage(mask))
maxBelow = max(grayImage(~mask))

Best Answer

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