Splitting the Channels of Grayscale Image

Grayscale images have 3 identical channels (as far as I know). Is there any way that I can extract the only one channel and reproduce the image with copying the channel.

Thank you,

Grayscale images only have one channel. It would make no sense to have 3 channels of the same data.

Do you mean that RGB has 3 grayscale channels? Cause gray scale is of course only one.

Draw image supports extracting a channel from an image and drawing it as a grayscale image onto another frame buffer.