Measuring Diameter of Calibration Pin
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I want to measure the diameter of the pin but getting a bad edge detection image. Can someone help me to further improve it?
My edge detection image:
My coding:
%% Read and Binarize
load image.mat
I4 = imgaussfilt(I3);
I4 = I4 <120;
%%
I5 = edge(I4,'Sobel');
imshow(I5)
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Accepted Answer
Image Analyst
on 28 Nov 2019
Why are you doing edge detection???? I see no need for that. If the edges are about where you put them, then try thresholding and getting the area and divide by the width:
mask = grayImage < someValue;
mask = imfill(mask, 'holes');
diameter = nnz(mask) / size(mask, 2); % height = area / width. Answer is in pixels.
It's trickier if you want the inner, instead of outer, dark thing.
5 Comments
Image Analyst
on 30 Nov 2019
Do you have another, more trusted method? If not, then why do you doubt the image analysis? Why do you assume it's wrong if you don't have another more trusted method? If it's the only thing you have that gives you an answer, then why do you doubt it?
What you really need to ask is if the image analysis meets your needs. For example does it properly identify diameters that are for usable parts and unusable parts? If not, you can construct an ROC curve.
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