Thread Subject: counting

hi everyone i m currently doing my seventh semester project and one of my module is to count the number of objects from a video i finished the tracking module and have each frame in which only the moving objects are there, i have it as both binary n grayscale image now i can count the object in per frame but wen given a video i should count how many objects have passed i m searching for an alogrithm or technique to do so please help me if anyone knows any techinques for this just provide me the links for that

                          thanks in advance