what do I get by calling 'PixelIdxList'?
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Hi! I recently using 'PixelIdxList' in the 'regionprop' function to calculate the color of the particle I labeled. But I don't really understand what color that 'PixelIdxList' gives?
I mean, I extract the 'PixelIdxList' from a RGB image, and calculate the mean value of pixels. But as we know, RGB image has red, green and blue in its array. When I calculate the mean(PixelIdxList) in an RGB image, I only get one value. So what colour does this mean value present?
My goal is to generate the mean grey value from the RGB image. Can I use this mean value from PixelIdxList?
Thank you!
3 Comments
Walter Roberson
on 28 May 2018
Approximate translation:
Good evening please how I can convert the pixels of stats (i) .area to image in matlab for example I have the result as follows cc # 1 - area 202965 nuemoro of pixel and size I like the poster in a binary image
Image Analyst
on 28 May 2018
marwa, you can't convert an area (a single scalar), or a list of pixel values in an irregularly-shaped blob, into an image - you need more than that. See my Image Segmentation Tutorial to see how you can crop out the regions from the image into sub-images using the bounding box from regionprops(), and imcrop(). Start your own question with your own image if you need more help.
Accepted Answer
Walter Roberson
on 4 Nov 2017
PixelIDxList does not give any image value. PixelIDxList gives array locations.
R = original_image(:,:,1);
G = original_image(:,:,2);
B = original_image(:,:,3);
blobinfo = regionprops(BWorLabeledImage, 'PixelIdxList');
one_idxlist = blobinfo(1).PixelIdxList;
R_in_region = R(one_idxlist);
G_in_region = G(one_idxlist);
B_in_region = B(one_idxlist);
mean_R_in_region = mean(R_in_region);
mean_G_in_region = mean(G_in_region);
mean_B_in_region = mean(B_in_region);
14 Comments
Walter Roberson
on 4 Dec 2022
DGM
on 4 Dec 2022
Augh. I was thinking too much about addressing pagewise.
I don't have time to fix it now.
More Answers (1)
Image Analyst
on 4 Nov 2017
PixelIdxList is the linear index of pixels in the blob.
From what you say, it appears you want the PixelValues measurement instead.
4 Comments
Image Analyst
on 6 Nov 2017
No. You wrote the code incorrectly. See Walter's answer for the correct version. Again, your code is not correct.
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