How to change 1 channel image to 3 channel

I have several grayscale images with channel 1, then I want to convert it to RGB channel 3 image, how do I change it?

Answer 1

[Image Analyst]

Try cat() to stack the gray scale image into 3 slices (color channels):

rgbImage = cat(3, grayImage, grayImage, grayImage);

It will be an RGB image though the only colors will be gray since there is no difference between the three different color channels. It will be a 3-D image with the z-direction (third index) being the color channel index.

[evianita dewi]

this is very helpful, thank you!!

[Muhammad Kamran]

Thanks a lot.

It's very helpful.

Answer 2

[DGM]

Alternative to using cat(), the same can also be done a couple other ways.

You can use repmat()

rgbpict = repmat(graypict,[1 1 3]);

... or you can even use basic indexing:

rgbpict = graypict(:,:,[1 1 1]);