基于PIL滤波计算去噪算法的验证码识别  

CAPTCHA Identification based on Image Denoising with PIL Filter

作　　者：姚轶崭 陈利[1] 王禹[1] 田永兴[1] 

机构地区：[1]中国信息安全测评中心,北京100085

出　　处：《计算机安全》2012年第11期40-45,共6页Network & Computer Security

摘　　要：验证码图片是互动应用系统用以阻止自动化程序恶意行为的重要人机区分技术,其设计和实用安全性直接涉及到应用系统的正常使用。为研究国内验证码实用安全性,设计实现一种验证码识别算法模型,对国内的验证码类型进行了实验和分析。实验结果表明,实用中的验证码识别率通常在50%以上,某些甚至达到100%,难以起到对自动化程序的阻碍作用。表明验证码实用技术还应做较大改进。CAPTCHA image is the major technique used by forums to tell computers and humans apart,SO that its security is of importance in internet usage.To learn about domestic CAPTCHA images,this paper proposes and implements a model of CAPTCHA image recognition algorithm,and tests almost all image types used in domestic forums.Experiment results indicate that a large part of CAPTCHA images have a recognition rate above 50%,and some with 100%,both of which Can hardly block automatic machines.In term s of its practicality,this paper further classifies them into four categories,only to find the optimal category is blank,which means CAPTCHA image technology needs great enhancements.

关 键 词：验证码 自动识别 INTERNET安全 

分 类 号：TP393.08[自动化与计算机技术—计算机应用技术]