- ABBYY歪斜校正，然后另存“TIFF彩色LZW压缩”
- https://github.com/barrer/scan-helper/blob/master/scan_helper_png.py 转为黑白png
- https://github.com/barrer/scan-helper/blob/master/component/remove_image_exif.py 删除黑白png的exif信息
- 用Adobe Acrobat DC 合并png为单个pdf
原文：http://www.cnblogs.com/whycnblogs/p/8034276.html
