Extracting set of data around local maxima/minima

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Konstantinos Belivanis 2015-5-2

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回答： Konstantinos Belivanis 2015-5-6

Hello all,

as the title says I would like to extract sets of data around local maxima/minima. Depending on the results I'll get I might need more than two.

To explain a bit further I have two column vectors (A, B) corresponding to the x and y axis of the picture attached. So I would like to locate the minimum and extract the area of +/- 30 points around it in other column vectors (say A1, B1), and the continue for the remaining data for the next minimum and so on (A2, B2) and (A3, B3)....

I hope I was clear.

Thank you in advance!

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Answer 1

Image Analyst 2015-5-2

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https://ww2.mathworks.cn/matlabcentral/answers/214663-extracting-set-of-data-around-local-maxima-minima#answer_177488

在 MATLAB Online 中打开

Try using imregionalmin() or imregionalmax(). Then expand outwards with imdilate(). Then use the PixelValues option of regionprops to extract the values from the gray level image for each blob. Basically

binaryImage = imregionalmax(grayImage);
binaryImage = imdilate(binaryImage, true(30));
labeledImage = bwlabel(binaryImage);
measurements = regiopnprops(labeledImage, 'PixelValues');

or something pretty close to that. Good luck.