How to programmatically determine zone mismatches on identical images?

Question

Image processing

All good afternoon.
Description of the situation: The company has few car parks around and inside the building. The principle of distribution of seats: "who first got up, that and slippers." You can ride through the levels for a long time, and for example, free space will be on the street, etc. All car parks are equipped with cameras. There is access to records.
Desired result: a mobile application that will report how many free places are now and where they are.
Problem: Please tell me a software that can automatically compare current parking photos with "reference" ones (all places are free). And give an array of results to the cloud.
Thank you.