MATLAB: Nonzero pixels in black image?!

blackImage Processing Toolboxperimeterpixel value

In an image process, I have got an image which after being inverted (to calculate the perimeter), it becomes absolutely black on screen. But when I see the pixel values, the last row and column are not zero!

why?

I mean when you sum the pixels, it is not zero!, while the image is completely black!

Thanks!

Steven

Best Answer

Your display is not set up to display a color that dark notably differently than true black. This is proper behaviour. Remember, a pixel value of 1 (out of 255) is not very bright.

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Hi, You can use the Wavelet Toolbox function dyadup

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However, essentially what you are doing is already done in the inverse 2-D DWT. Just out of curiousity, why are you not just using the full powerful machinery of the Wavelet Toolbox? (idwt2, waverec2)

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Best Answer

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