MATLAB: Pixels and their locations

imageImage Processing Toolboxlocationpixelsshow

For instance, I have a grayscale image. For that image, say that I'm interested in viewing pixels with intensity value 77. For that, I did the following:
    imshow(I(I==77))
But, in this case, I got a figure with something like a vertical thin line and doesn't show a meaningful image.
It seems we should refer to the locations of those pixels.
What should we do in this case in order to retrieve a meaningful image showing the pixels of interest?
Thanks.

Best Answer

That's because (I==77) is a 2D binary image (true/false) but when you pass a binary/logical image into an array in MATLAB, you get a column vector out. What you want to do is to mask the image:
mask = (I==77); C% Create binary (logical) mask.
maskedImage = I .* uint8(mask);  % Multiply mask by image.
imshow(maskedImage); % Display maskedImage
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