Simple OpenCV project for RaspberryPi Camera

For anyone that is an expert in OpenCV this should be a really easy project. Must be written in python and able to run on a raspberry pi 3 with the pi camera. Here is what the project must do: Using a frame difference to count people moving in and out of the scene in real time. The camera will be position so that the scene can change slowly over time so the initial frame that is used for the frame difference should actually be an average of that last x frames. X should be adjustable but start with X = 200. In addition to that. The program needs to support the ability to define regions in the frame and keep a count of people in each of the regions. The regions are defined in a 2 dimensional array of pixel locations that define a polygon shape. A count is stored in another array with aligning indexes. The device also needs to track from which direction (number 0 to 3) each person enters and leaves the frame from. This is not an extremely difficult project and we are looking for a bid between $100 and $200.