MATLAB: Applying same function to different image areas

image analysisimage processingimage segmentation

Hi everyone. I uploaded an image, cropped it and divided it into 4 stripes like this:
    >> I = imread(fullImageFileName);
    [Crop, rect] = imcrop(I);
    [r, c, p] = size(Crop);
    Crop(1:r/4:r,:,:)=255;
    A = Crop(1:r/4,:,:);
    B = Crop(r/4+1:r/2,:,:);
    C = Crop(r/2+1:3*r/4,:,:);
    D = Crop(3*r/4+1:r,:,:);
    imshow(Crop);
And I have a function from SimpleColorDetectionByHue() that is defined here:
   >> function [meanHSV, areas, numberOfBlobs] = MeasureBlobs(maskImage, hImage, sImage, vImage)
try
  [labeledImage, numberOfBlobs] = bwlabel(maskImage, 8);     % Label each blob so we can make measurements of it
  if numberOfBlobs == 0
    % Didn't detect any blobs of the specified color in this image.
    meanHSV = [0 0 0];
    areas = 0;
    return;
  end
  % Get all the blob properties.  Can only pass in originalImage in version R2008a and later.
  blobMeasurementsHue = regionprops(labeledImage, hImage, 'area', 'MeanIntensity');   
  blobMeasurementsSat = regionprops(labeledImage, sImage, 'area', 'MeanIntensity');   
  blobMeasurementsValue = regionprops(labeledImage, vImage, 'area', 'MeanIntensity');   
  
  meanHSV = zeros(numberOfBlobs, 3);  % One row for each blob.  One column for each color.

  meanHSV(:,1) = [blobMeasurementsHue.MeanIntensity]';
  meanHSV(:,2) = [blobMeasurementsSat.MeanIntensity]';
  meanHSV(:,3) = [blobMeasurementsValue.MeanIntensity]';
  
  % Now assign the areas.
  areas = zeros(numberOfBlobs, 3);  % One row for each blob.  One column for each color.
  areas(:,1) = [blobMeasurementsHue.Area]';
  areas(:,2) = [blobMeasurementsSat.Area]';
  areas(:,3) = [blobMeasurementsValue.Area]';
catch ME
  errorMessage = sprintf('Error in function %s() at line %d.\n\nError Message:\n%s', ...
    ME.stack(1).name, ME.stack(1).line, ME.message);
  fprintf(1, '%s\n', errorMessage);
  uiwait(warndlg(errorMessage));
end
return; % from MeasureBlobs()
And recalled in the main as here:
>> % Measure the mean HSV and area of all the detected blobs.
  [meanHSV, areas, numberOfBlobs] = MeasureBlobs(coloredObjectsMask, hImage, sImage, vImage);
  if numberOfBlobs > 0
    fprintf(1, '\n----------------------------------------------\n');
    fprintf(1, 'Blob #, Area in Pixels, Mean H, Mean S, Mean V\n');
    fprintf(1, '----------------------------------------------\n');
    for blobNumber = 1 : numberOfBlobs
      fprintf(1, '#%5d, %14d, %6.2f, %6.2f, %6.2f\n', blobNumber, areas(blobNumber), ...
        meanHSV(blobNumber, 1), meanHSV(blobNumber, 2), meanHSV(blobNumber, 3));   
      end
I want to repeat this function for the 4 regions of my image and display the 'regional' results, then maybe group the 'total' results in a matrix using a sum. How can I do it? Thanks a lot 🙂

Best Answer

Just call it 4 times
[meanHSVA, areasA, numberOfBlobsA] = MeasureBlobs(maskImageA, hImageA, sImageA, vImageA)
[meanHSVB, areasB, numberOfBlobsB] = MeasureBlobs(maskImageB, hImageB, sImageB, vImageB)
[meanHSVC, areasC, numberOfBlobsC] = MeasureBlobs(maskImageC, hImageC, sImageC, vImageC)
[meanHSVD, areasD, numberOfBlobsD] = MeasureBlobs(maskImageD, hImageD, sImageD, vImageD)
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