https://blog.csdn.net/andylanzhiyong/article/details/81807425
官方例子：
https://github.com/tesseract-ocr/tesseract/wiki/APIExample
一个感觉很棒的详细教程：
https://www.jianshu.com/p/3df039e42986
训练
https://ivanzz1001.github.io/records/post/ocr/2017/09/09/tesseract-fonts#2-%E5%AD%97%E4%BD%93%E7%9A%84%E5%AE%89%E8%A3%85
https://ivanzz1001.github.io/records/post/ocr/2017/09/09/tesseract-fonts
https://www.jianshu.com/p/70e4d55fa85a
https://blog.csdn.net/chudongfang2015/article/details/51920191