I want to use color to annotate a monochrome image.
As I understand it, first I need to convert the single channel monochrome image to a 3 channel gray scale image with BGR channels all set the same. Then I can overlay color annotations on the gray scale image.
It is the first part that has me stumped: It seems like .clone, .copyTo, cvtColor all force the output to the same number of channels as the input?
How do I create a 3 channel copy of a single channel image?