对单数字的验证码，通过一些OCR引擎，如：tesseract，AspriseOCR很容易解决问题。但碰到如CSDN论坛这中图形验证码就比较麻烦，必须先通过预处理。使图象二值化，黑白灰度，增加亮度。-The single digit verification code, through the OCR engine, such as: Tesseract, AspriseOCR very easy to solve the problem. But the encounter such as CSDN forum the graphic code is more trouble, must first by pretreatment. The two binary images, gray, increasing the brightness.