https://github.com/tesseract-ocr/langdata
https://www.jianshu.com/p/6c4424252168 （中）
https://livezingy.com/win10-tesseract4-1-lstm-training/
https://zhuanlan.zhihu.com/p/58366201 （知乎）
https://livezingy.com/train-tesseract-lstm-with-make-on-windows/amp/ (wordlist, num, punc的问题解决)
https://github.com/tesseract-ocr/tesstrain （tesseract makefile 训练脚本）