How can I select the gray patches
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I have this picture and I tried to wrote a code to select these 12 grey patches. The problem I am facing is that some patches are not detected properly. How can I correctly select these 12 ROI.
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/406715/image.jpeg)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/406720/image.jpeg)
Fig 1: Input Image Fig 2: It miss the 2 ROIs and have false detection.
CropImg=imread('patchc.jpg');
img=rgb2gray(CropImg);
rangefiltv= rangefilt(img);
imshow(rangefiltv)
mask = rangefiltv >10;
mask=~mask;
mask = bwareafilt(mask, 12);
stat = regionprops(mask,'boundingbox');
imshow(CropImg); hold on;
for cnt = 1 : numel(stat)
bb = stat(cnt).BoundingBox;
rectangle('position',bb,'edgecolor','r','linewidth',2);
end
*Update
The Cropped image is from this image. The size of the picture may varry. ![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/407025/image.jpeg)
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/407025/image.jpeg)
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Answers (1)
Image Analyst
on 8 Nov 2020
This looks like a computer graphics image where the gray patches will be in exactly the same location for any similar image, so you can just hard code in the coordinates of the corners. If that's not true, then post an actual image, not a perfect computer graphics one, so we can write segmentation code for it. Something like
mask = grayImage ~= backgroundGrayLevel;
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