tesseract 4.0.x
https://github.com/tesseract-ocr/tesseract/wiki/NeuralNetsInTesseract4.00

CRNN
http://xiaofengshi.com/2019/01/23/%E6%B7%B1%E5%BA%A6%E5%AD%A6%E4%B9%A0-TextDetection/