Automatic Correction Algorithm for Declining CAPTCHA
Ding Yue-wei · Jisuanji gongcheng · 2011
Considering the widely used CAPTCHA on Internet is still at the risk of low security,a novel automated correction algorithm for declining numbers is proposed from the angle of recognition,through which can automatically find the bottom and azimuth tilt of the characters.The algorithm involves three aspects which are the coordinate of digital numbers,channel search and channel analysis.Among them,the first step which based on the early preprocessing process can be used to verify the tilt while the channel search process determines the connection of the characters and provides information for the channel analysis stage.Experimental results show that it can reach nearly 100% accuracy of the correction rate for standard characters and 95% of the average recognition rate for characters with micro-deformation.