MATLAB: Regionprops and standard deviation (binary image)

binary imageImage Processing Toolboxregionpropsstd

Hi everyone, i am using the function" regionprops" to get the largest perimeter in my binary image. I have got the value of the largest perimeter but still need to have its standard deviation. Does anyone know how to get this std? Thank you very much

Best Answer

When you do the regionprops() also ask for 'PixelIdxList' . When you find the region with the largest perimeter, extract its PixelIdxList. Use that PixelIdxList to index the 2D image, and take std() of the pixels that are returned.

If your original image was color, then sometimes the easiest is to break it into 3 variables and use PixelIdxList on each. That is not the only way, but it is easy to understand whereas the conversion of 2D linear indices to appropriate 3D indices can be a bit tricky to understand.

Related Solutions

MATLAB: How can i separate all the connected regions in a binary image and display them individually.

Use bwlabel() and ismember

[labeledImage, numRegions] = bwlabel(binaryImage);
props = regionprops(labeledImage, 'Area')
% Compute all the areas.
allAreas = [props.Area]
% Display each blob in its own figure.
for k = 1 : numRegions
    thisRegion = ismember(labeledImage, k);
    figure;
    imshow(thisRegion);
    drawnow;
end

MATLAB: Number of Object in binary image

Try this:

bw = imread('bw.png');
if ndims(bw) > 1
	bw = bw(:,:,1);
end
% Threshold
bw = bw > 128;
subplot(1, 2, 1);
imshow(bw, []);
% Fill holes
bw = imfill(bw, 'holes');
% Get areas
props = regionprops(bw, 'Area');
sortedAreas = sort([props.Area], 'descend')
% Looks like we need to throw away any blobs less than 1000 pixels or so
bw = bwareaopen(bw, 1000);
subplot(1, 2, 2);
imshow(bw);
% Count the blobs
[labeledImage, numBlobs] = bwlabel(bw);
fprintf('Found %d shapes.\n', numBlobs);

Best Answer

Related Solutions

MATLAB: How can i separate all the connected regions in a binary image and display them individually.

MATLAB: Number of Object in binary image

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