- tesseract-ocr: https://github.com/tesseract-ocr free
- baidu: https://ai.baidu.com/tech/ocr free 50000 call pre day
- tencent: https://cloud.tencent.com/act/event/ocrdemo free 1000 call pre month
- alibaba: https://duguang.aliyun.com/experience?type=doc&midtype=fulldoc&subtype=general free 500 per year
baidu, alibaba and tencent are the top 3 IT in china
The best for now is tencent I think
go ./results for details