I am using Mobile Vision API (https://developers.google.com/vision/) on Android to detect text in images.
However, it never seems to be able to detect single numbers such as "3" or "6", but can easily detect "23" or "56" and also coordinates involving single numbers such as "d4".
So my question is if the Mobile Vision API cannot detect single numbers?
The answer to your question is yes. Mobile Vision cannot detect isolated numbers consisting of a single digit. Actually I have tried several other SDKs including the commercial one and so far have not found any that can detect isolated single digit numbers. Reason being they are considered as noice therefore they are to be ignored.
If there is any SDK that do not have this issue I am interested to know.