Which Matlab functions or examples should be used to (1) track distance from moving object to stereo (binocular) cameras, and (2) track centroid (X,Y,Z) of moving objects, ideally in the range of 0.6m to 6m. from cameras?
I've used the Matlab example that uses the PeopleDetector function, but this becomes inaccurate when a person is within 2m. because it begins clipping heads and legs.
The first thing that you need deal with, is in how detect the object of interest (I suppose you have resolved this issue). There are a lot of approaches of how to detect moving objects. If your cameras will stand in a fix position you can work only with one camera and use some background subtraction to get the objects that appear in the scene (Some info here). If your cameras are are moving, I think the best approach is to work with optical flow of the two cameras (instead to use a previous frame to get the flow map, the stereo pair images are used to get the optical flow map in each fame).
In MatLab, there is an option called disparity computation, this could help you to try to detect the objects in scene, after this you need to add a stage to extract the objects of your interest, you can use some thresholds. Once you have the desired objects, you need to put them in a binary mask. In this mask you can use some image momentum (Check this and this) extractor to calculate the centroids. If the images in the binary mask look noissy you can use some morphological operations to improve the reults (watch this).