A method for estimating a distance between a first target and a second target in an image is to be implemented using a distance estimation system that includes a processor module. In the method, the processor module is programmed to: generate an image depth map associated with the image; generate first position information associated with a first position which corresponds to the first target in the image, and second position information associated with a second position which corresponds to the second target in the image; and compute an estimate of a distance between the first target and the second target based on at least the image depth map, the first position information, and the second position information.