MATLAB: Crop coloured padding of image

coloured paddingcroppingimage processingpadding

So this is pretty much a follow-up question to this one I asked yesterday, but now I'm interested in cropping coloured padding (attachment for test-image-2.jpg). With the answer from Walter on the previous question, I tried to do it like this:
        I = imread('test-image-2.jpg');
        rI = I(:,:,1);
        gI = I(:,:,2);
        bI = I(:,:,3);
        Rw = all(rI == 237); %red channel value
        Gw = all(gI == 27); %green channel value
        Bw = all(bI == 36); %blue channel value
        %mask
        Rmaskc = all(Rw, 1);Rmaskr = all(Rw, 2);
        Gmaskc = all(Gw, 1);Gmaskr = all(Gw, 2);
        Bmaskc = all(Bw, 1);Bmaskr = all(Bw, 2);
        %set to 0
        rJ = rI; rJ(Rmaskr,:,:) = 0; rJ(:,Rmaskc,:) = 0;
        gJ = gI; gJ(Gmaskr,:,:) = 0; gJ(:,Gmaskc,:) = 0;
        bJ = bI; bJ(Bmaskr,:,:) = 0; bJ(:,Bmaskc,:) = 0; 
        %RED
        rJ( ~any(rJ,2), : ) = [];  %rows


        rJ( :, ~any(rJ,1) ) = [];  %columns


        %GREEN
        gJ( ~any(gJ,2), : ) = [];  %rows
        gJ( :, ~any(gJ,1) ) = [];  %columns
        %BLUE
        bJ( ~any(bJ,2), : ) = [];  %rows
        bJ( :, ~any(bJ,1) ) = [];  %columns
        IM = cat(3, rJ, gJ, bJ);
It crops the sides just fine (the small strokes on sides have different RGB values so guess thats ok), but the top/bottom is not getting cropped.
So I'm a bit confused on why the sides get cropped decently, but for some reason the top/bottom gets ignored

Best Answer

Try this:
rgbImage = imread('test-image-2.jpg');
rI = rgbImage(:,:,1);
gI = rgbImage(:,:,2);
bI = rgbImage(:,:,3);
subplot(2, 2, 1);
imshow(rgbImage);
title('Mask', 'FontSize', 16);
mask = ~((rI == 237) & (gI == 27) & (bI == 36));
subplot(2, 2, 2);
imshow(mask);
title('Mask', 'FontSize', 16);
[maskRows, maskColumns] = find(mask);
row1 = min(maskRows);
row2 = max(maskRows);
col1 = min(maskColumns);
col2 = max(maskColumns);
maskedRGBImage = rgbImage(row1:row2, col1:col2, :);
subplot(2, 2, 3);
imshow(maskedRGBImage);
title('Masked Image', 'FontSize', 16);
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