Recently, I focused on the AWS AI Services Extension developed by Ceyhun Özgün. This is an Extension that allows MIT App Inventor applications to easily take advantage of such recognition features. References  and  provide descriptions and demo programs. I've created a simple smartphone application like Fig.1 below, using this useful information as a reference.
Let me illustrate the recognition results in this diagram. Fig.1 (a) is an image of the US $2 bill. Immediately, “Money, Person, Dollar” was recognized. In addition, the text in the image was also recognized. In particular, the number “J045... 5A”, which is the id of the banknote, is also recognized precisely. Fig.1 (b), on the other hand, is an image of a notebook and books. It is recognized as “Book”, and the text of the titles of the books (although handwriting is also included) is almost accurate. I think it's great. These smartphone apps are fun to use wherever you take them!
The design part of this app is shown in Fig.2. Here, I used AppyBuilder. You can choose to take a picture now or use an image that you already have in your library. After that, recognition is performed automatically and the results of recognition of objects and text are displayed.
Next Fig.3 is the complete blocks of this app. Thanks to the Extension mentioned above, you will find that it has become a very concise program. In order to use this Extension, you need to set up an AWS account. In particular, be aware that you will give your AWS Services credentials on the first run. Details of this are also described in the literature . Thanks to Ceyhun Özgün!