How to make motion history image for presentation into one single image?

I am working on a project with gesture recognition. Now I want to prepare a presentation in which I can only show images. I have a series of images defining a gesture, and I want to show them in a single image just like motion history images are shown in literature.

My question is simple, which functions in opencv can I use to make a motion history image using lets say 10 or more images defining the motion of hand.

As an example I have the following image, and I want to show hand's location (opacity directly dependent on time reference).

an example image

I tried using GIMP to merge layers with different opacity to do the same thing, however the output is not good. output with gimp

Solution

You could use cv::updateMotionHistory
Actually OpenCV also demonstrates the usage in samples/c/motempl.c