how to measure distance between corners?

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sara 2014-10-4

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https://ww2.mathworks.cn/matlabcentral/answers/157345-how-to-measure-distance-between-corners

评论： sara 2014-10-19

vertical difference.bmp

I have detected some corners in labeled images,how can I measure vertical distance between corners,forexample plot a line at the top corner of each labeled image and measure the vertical difference to each other

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sara 2014-10-4

yeah it can be the difference in vertical coordinates too,i think

Guillaume 2014-10-4

Then, since you have detected the two corners, can't you just subtract their vertical coordinates?

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采纳的回答

Image Analyst 2014-10-4

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https://ww2.mathworks.cn/matlabcentral/answers/157345-how-to-measure-distance-between-corners#answer_153900

Just measure the bounding box with regionprops. A full demo is given in my Image Segmentation Tutorial: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

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sara 2014-10-19

编辑：sara 2014-10-19

在 MATLAB Online 中打开

will it give me the height of each blob?i want the measurement of the space between them,forexample there might be 2 person both 170 centimeters,but one stands on the first stair and the other on the third,so there is about 50 centimeters vertical difference between them,while both have the same height,. should I just add it at the end of the program?i just add this to the end of the codes,and it detects labeled images,area,but wont show height or top line,should I add imshow,or something,

if true
 measurements = regionprops(labeledImage, 'Area', 'BoundingBox');
% Loop extracting height and top row ("line") for each blob.
for k = 1 : length(measurements)
allHeights(k) = measurements(k).BoundingBox(3);
topRows(k) = measurements(k).BoundingBox(2);
end
end

I also choose these lines from your code,which is about area,and it detect different labeled iamges,but wont show area,and measuring,or top line

    if true
      originalImage =rgb2gray(imread('C:\Users\Sara\Desktop\good.jpg')); 
figure,imshow(originalImage);
thresholdValue = 100;
binaryImage = originalImage > thresholdValue;
figure,imshow(binaryImage);
labeledImage = bwlabel(binaryImage, 8);
figure,imshow(labeledImage);
coloredLabels = label2rgb (labeledImage, 'hsv', 'k', 'shuffle'); 
figure,imshow(coloredLabels);
blobMeasurements = regionprops(labeledImage, originalImage, 'all');   
numberOfBlobs = size(blobMeasurements, 1);
boundaries = bwboundaries(binaryImage);  
numberOfBoundaries = size(boundaries);
for k = 1 : numberOfBoundaries
  thisBoundary = boundaries{k};
  plot(thisBoundary(:,2), thisBoundary(:,1), 'g', 'LineWidth', 2);
end
for k = 1 : numberOfBlobs           
  blobArea = blobMeasurements(k).Area;    
end
allBlobAreas = [blobMeasurements.Area];
for k = 1 : numberOfBlobs          
    thisBlobsBoundingBox = blobMeasurements(k).BoundingBox;  
    subImage = imcrop(originalImage, thisBlobsBoundingBox);
    figure,imshow(subImage);
end
measurements = regionprops(labeledImage, 'Area', 'BoundingBox');
% Loop extracting height and top row ("line") for each blob.
for k = 1 : length(measurements)
  allHeights(k) = measurements(k).BoundingBox(3);
  topRows(k) = measurements(k).BoundingBox(2);
end
allAreas = [measurements.Area];
[sortedAreas, sortIndexes] = sort(allAreas, 'Descend');
    end

Image Analyst 2014-10-19

To show top lines, use the line() or plot() function on the original (not cropped) image. To display bounding box, use the rectangle() function on the original image, not the cropped subImage.

sara 2014-10-19