I'm new to computer vision and I want to solve the task of recognizing the game units of the game Clash Royale in the screenshot. Briefly, there are about 70 different types of gaming units belonging to two teams (they differ a little in colors and some are visible in front, others with backs). I want to find game units on the screenshot and classify their type of unit (then health and the team).
What are the best tools for task like this? What libraries will I use to simply teach the model? How many teaching examples do I need to learn the model? It seems that the quality of the screenshots is quite good and the images are clear. To what size should I reduce the screenshoot to get a good model and its speed? Maybe someone had a similar experience? I think about CNN or a lot of HAAR cascades for each of the types of units, but I would like to receive advice.