pixel bin relation imhist
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Hello,
I'm using imhist, and I would like to assign a default value to each pixel whose intensity appears less than a fixed number of times in the image. In other words, I would like a function whose input is an image and the output is its histogram and the concerned pixels (their location) for each bin of the histogram. I could write a script doing that, but I'm looking for a direct method, as optimized as possible.
Thanks for your help
Sylvain
1 Comment
Adam
on 22 Aug 2017
Well, I'm pretty sure there isn't a single inbuilt function that will do it all for you so you'll have to write some code. It depends what you consider a 'direct' method vs whatever you think the alternative is.
Answers (3)
Jan
on 22 Aug 2017
The question is not clear. What are " concerned pixels (their location)" exactly?
I assume you want to start with:
[counts, binLocations] = imhist(I); % Or imhist(I, n) with a suitng n?
And now you want set all binLocations with counts<limit to a certain value? How would the script you have mentioned look like?
3 Comments
Adam
on 22 Aug 2017
Well, you haven't shown your script so who knows if there is a better way or not until you do?!
Jan
on 22 Aug 2017
Edited: Jan
on 22 Aug 2017
Try this:
Edge = linspace(0,1,256);
[N, Edge, Bin] = histcounts(f, Edge);
V = (N < (F * max(N)));
Mask = V(Bin);
f(Mask) = mean(f(:));
histcounts determines the frequency of values. I've used the simpler linspace(0,1,256) here, because the intention of your bl1 and bl2 is not clear to me. You can adjust the wanted edges as you want. Then a mask is created, which is TRUE for all values, which appear less than F times the most frequent value.
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Image Analyst
on 22 Aug 2017
You can compute the color frequency image http://www.mathworks.com/matlabcentral/fileexchange/28164-color-frequency-image
Then simply threshold it and assign the new value you want.
pixelsToReplace = cfImage < someThresholdValue;
cfImage (pixelsToReplace) = desiredValue;
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