how do I select only the segmented region from a original image in MATLAB

I need a little help.

I have a MATLAB code in which I've segment out an original image into multiple segments. Now I want to select only a specific segmented area and give it as an input to my function. I have attached my segmented image in which desired part is shown along with the black pixels. How do I select only the desired region, I don't want black pixels region.

Thanks,

for k = 1:max(max(l))
    color = img;
    color(rgb_label ~= k) = 0;
    segmented_images{k} = color;
    image = double(segmented_images{k})/255.0;
end

Answer 1

[Matt J]

You could do,

S=regionprops(rgb_label,img,'Image')

[kashif Mobeen]

Thank you so much for responding.

By using this command it has save all the segmented regions in the S variable. so how can I access every region separately to use as an input to my function??

Thanks.

[Matt J]

S(k).Image is the k-th labelled image region.

[kashif Mobeen]

How can I display every region?

imshow(S(1))??

imshow(S(2))??

......

[Matt J]

For example,

for k=1:numel(S)
figure(i); imshow(S(k).Image)
end

Answer 2

[Image Analyst]

You could do

mask = max(rgbImage, [], 3) > 0;
[r, c] = find(mask); % Find rows and columns of non-zero pixels
row1 = min(r);
row2 = max(r);
col1 = min(c);
col2 = max(c);
croppedImage = rgbImage(row1:row2, col1:col2, :);

[kashif Mobeen]

Thank you so much for your response.

I tried this one but the issue is, I don't have perfectly squared segmented part so I can crop that region. I've a non-unifrom regions so when I tried this for cropping, some part of the black pixels are remain there in the cropped image, that I don't want.

see attached cropped image using above code.

[Matt J]

some part of the black pixels are remain there in the cropped image, that I don't want.

What do you want them replaced with?

[kashif Mobeen]

Is it possible that I can extract only the segmented image in the exact shape as it is ?? In this code the region is being cropped in a square window that also includes surronding unwanted black pixels.

[Matt J]

No, there is no such thing as a non-rectangular image.

[Image Analyst]

Matt's right. Why do you want that anyway? Do you want transparent pixels, like I think PNG images can have so that you can see the background. I never do that since it has no real use in image analysis. If you think you need transparent pixels, explain why? Because I would counter that you don't, even though you think you might. It's not necessary to do any kind of image analysis on the image.