Multiply 2 opencv images together

First chance to sit down with OF after the recent decode Lab at the V&A.

Picking up from there I’m wondering how to multiply two images together. I’m working with the OpenCV example - I have my thresholded image and I want to multiply that by the original image to get a colour image.

Do I have to getpixels and then go through them one by one multiplying the relevant values?

Or is there something set up to do that already, bearing in mind the images have different bit depths.

I’m a bit stuck as to where to find help for things like this. Looking through the OfxOpenCV source gives clues, but ones I don’t yet understand.

Any pointers would be well handy!