Object recognization tool or algorithm recommendation

Hi, I am searching for the tool or algorithm for the object detection.

The case is: a few known objects(which means I can create a set of sample images to train in advance), and identify them on a table(include a certain degree of objects occlusion), and single out the specific kind I need.

As the time is kinda limited and I am new to fields like computer vision or machine learning, it would be better if I can get work on a few tools rather than try all of the relative things around.

a simple illustration is as below(the right one is target effect):