How do I implement the feature that you see in shopping apps, Google or BING, the camera icon that allows users to take a photo and then it will show matches against its database of photos?

Are those features we see can only be powered by Cloud providers API, eg Amazon AWS and Microsoft Azure, or are there available Delphi algorithms that can take care of it?

I saw a Delphi algorithm but there are limitations such as photos cannot be more than a certain degrees different and size difference cannot be more than x%.

The professional apps image recognition works even the background is cluttered.

How do I implement such a function in Delphi without calling cloud APIs?