MATLAB Answers

Measure distance between two object with same color automatically

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bimo prasetyo
bimo prasetyo on 6 Oct 2019
Edited: Image Analyst on 22 Jan 2020
how do I measure distances in object which has the same colors from this image, for example the distance between "red" and "red. Thanks for your help.multicolor.jpg

Answers (1)

Image Analyst
Image Analyst on 6 Oct 2019
First you need to segment the image to find all the "red" regions. I have some demos for color segmentation in my File Exchange. Or you could use the Color Thresholder app on the apps tab of the tool ribbon.
Once you have a mask of the red regions, you can ask regionprops() for the centroids.
Then, with the centroids, you can use pdist2(), in the Statistics and Machine Learning Toolbox, to find the distance of every blob to every other blob.

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bimo prasetyo
bimo prasetyo on 8 Oct 2019
yes Image Analyst , I want to draw a line between two centroids which the line represents their distances. I hope you can correct the coding above or give the correct coding.
Image Analyst
Image Analyst on 10 Oct 2019
Use the Color Thresholder app on the Apps tab of the tool ribbon to create a mask. Then call regionprops(mask, 'Centroid') to get the centroids. Then use plot() or line() to draw a line between each pair of centroids. Can you try this?
props = regionprops(mask, 'Centroid');
allCentroidsXY = vertcat(props.Centroid);
numBlobs = length(props);
hold on; % Don't let lines blow away image.
for k1 = 1 : (numBlobs - 1)
x1 = allCentroidsXY(k1, 1);
y1 = allCentroidsXY(k1, 2);
for k2 = (k1 + 1) : numBlobs
x2 = allCentroidsXY(k2, 1);
y2 = allCentroidsXY(k2, 2);
line([x1, x2], [y1, y2], 'Color', 'r', 'LineWidth', 2)
end
end

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