delphi验证码识别学习之图像的灰度化、二值化及反色 ,本文的方法同时适用于GDI+图像和Delphi的TGraphic图像。 -delphi image verification code recognition learning of graying, binarization and anti-color, method of this article apply to both GDI+ image and TGraphic image of Delphi.