MATLAB: How To remove black color from gray-scale image

blackchange colorgraygrayscaleimage processing

Hi guys

i was wondering how can i remove a black color from the grayscale image? or can i just change the black into any other lighter color?

thank you

It depends on the format of the image. For a UINT8 array:

Img = randi([0,255], 100, 100, 'uint8');  % Test data
Img(Img == 0) = 127;

Now black is replaced by a medium grey. The procedure for double format is equivalent, but a medium grey is 0.5.

Try this to create a grayscale image:

whiteImage = 255 * ones(N, M, 'uint8');
imshow(whiteImage);

To create an RGB image, try this:

whiteImage = 255 * ones(480, 640, 3, 'uint8');
imshow(whiteImage);

You can plot it using histcounts().

counts = histcounts(grayImage, 0:256)
plot(counts)