粘連字符驗證碼的識別研究
發(fā)布時間：2018-10-05 19:05
【摘要】：二十一世紀是信息爆炸的時代,互聯(lián)網(wǎng)技術高速發(fā)展,給人們生活帶來了極大的便利,同時各類網(wǎng)絡資源濫用問題也引起了研究者的高度重視。驗證碼機制應運而生,被運用到各大網(wǎng)站中,用以防止資源被計算機程序惡意占用以及保護信息的隱私性。對驗證碼的識別研究,不僅可以找出驗證碼設計的漏洞來防止程序的自動攻擊,也在無形中推動了數(shù)字圖像處理、模式識別和機器學習等技術的發(fā)展。本文主要針對粘連字符驗證碼進行識別研究,這類驗證碼主要的特點是字符間存在粘連,有簡單粘連亦有復雜粘連。著重選取了六個網(wǎng)站的登錄或郵箱注冊驗證碼,分別是交通銀行、CSDN、知乎、新浪郵箱、新浪微博和網(wǎng)易驗證碼,根據(jù)它們各自的特點提出了相應的破解算法。論文的主要研究工作和成果如下:1、針對交通銀行字符傾斜粘連的問題,提出了一種改進的投影分割算法,主要在投影分割算法的基礎上加入動態(tài)旋轉(zhuǎn),提升了投影分割點判斷的準確性;·針對CSDN字符緊密粘連的情況,將投影分割與字符寬度和像素點和結合。最終二者分割率均能達到近100%。2、對知乎驗證碼二值化后字符輪廓殘缺的情況,提出了一種基于分級區(qū)域點搜索的輪廓線修補算法;對傳統(tǒng)的連通域分割算法進行了改進,使其在有字符碎塊的情況下也能成功分割;對含曲線噪聲的新浪驗證碼,直接利用連通域塊的凹凸性和外圍像素點信息,辨別出噪塊中的字符碎片。3、針對新浪微博扭曲傾斜粘連字符的分割問題,提出一種改進的滴水算法,主要在滴水算法的基礎上加入旋轉(zhuǎn)卡殼算法和豎直投影,既解決傾斜問題又能成功分割粘連字符;對設計復雜的網(wǎng)易驗證碼,主要將連通域分割、豎直投影和滴水分割三種算法相結合,利用它們各自的分割特征,成功從圖片中逐步分離出各字符。
[Abstract]:The 21 century is the era of information explosion. The rapid development of Internet technology has brought great convenience to people's life. At the same time, the abuse of various network resources has attracted great attention of researchers. The verification code mechanism has come into being and has been applied to various websites to prevent resources from maliciously occupied by computer programs and to protect the privacy of information. The research on the identification of the verification code can not only find the loophole in the design of the verification code to prevent the automatic attack of the program, but also promote the development of digital image processing, pattern recognition and machine learning technology. This paper focuses on the identification of adhesive character verification code. The main characteristics of this kind of code are that there is adhesion between characters, simple adhesion and complex adhesion. This paper selects six websites' login or mailbox registration verification code, which are CSDN, Zhihu, Sina mailbox, Sina Weibo and NetEase respectively, and puts forward the corresponding decoding algorithm according to their respective characteristics. The main research work and results of this paper are as follows: 1. Aiming at the problem of skew adhesion of characters in Bank of Communications, an improved projection segmentation algorithm is proposed, which mainly adds dynamic rotation to the projection segmentation algorithm. The accuracy of judging projection segmentation points is improved, and the projection segmentation is combined with character width and pixel points for the case of close adhesion of CSDN characters. In the end, the segmentation rate of both can reach nearly 100. 2. In order to solve the problem that the character contour is incomplete after binarization, a contour repair algorithm based on hierarchical region search is proposed, and the traditional connected domain segmentation algorithm is improved. In the case of character fragments, it can also be successfully partitioned. For the Sina certification code with curve noise, it directly utilizes the concavity and convexity of the connected domain block and the information of the peripheral pixels. The character fragment. 3 in the noise block is identified. Aiming at the segmentation problem of Sina Weibo's twisted oblique conglutination characters, an improved drip algorithm is proposed, which mainly adds the rotation clamping algorithm and vertical projection on the basis of the drop water algorithm. It can not only solve the problem of inclination but also successfully divide the adhesive characters. For the complex design of NetEase CAPTCA, it mainly combines three algorithms: connected domain segmentation, vertical projection and drip segmentation, and makes use of their respective segmentation characteristics. The characters were successfully separated from the picture step by step.
【學位授予單位】：南京理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TP309
本文編號：2254529
[Abstract]:The 21 century is the era of information explosion. The rapid development of Internet technology has brought great convenience to people's life. At the same time, the abuse of various network resources has attracted great attention of researchers. The verification code mechanism has come into being and has been applied to various websites to prevent resources from maliciously occupied by computer programs and to protect the privacy of information. The research on the identification of the verification code can not only find the loophole in the design of the verification code to prevent the automatic attack of the program, but also promote the development of digital image processing, pattern recognition and machine learning technology. This paper focuses on the identification of adhesive character verification code. The main characteristics of this kind of code are that there is adhesion between characters, simple adhesion and complex adhesion. This paper selects six websites' login or mailbox registration verification code, which are CSDN, Zhihu, Sina mailbox, Sina Weibo and NetEase respectively, and puts forward the corresponding decoding algorithm according to their respective characteristics. The main research work and results of this paper are as follows: 1. Aiming at the problem of skew adhesion of characters in Bank of Communications, an improved projection segmentation algorithm is proposed, which mainly adds dynamic rotation to the projection segmentation algorithm. The accuracy of judging projection segmentation points is improved, and the projection segmentation is combined with character width and pixel points for the case of close adhesion of CSDN characters. In the end, the segmentation rate of both can reach nearly 100. 2. In order to solve the problem that the character contour is incomplete after binarization, a contour repair algorithm based on hierarchical region search is proposed, and the traditional connected domain segmentation algorithm is improved. In the case of character fragments, it can also be successfully partitioned. For the Sina certification code with curve noise, it directly utilizes the concavity and convexity of the connected domain block and the information of the peripheral pixels. The character fragment. 3 in the noise block is identified. Aiming at the segmentation problem of Sina Weibo's twisted oblique conglutination characters, an improved drip algorithm is proposed, which mainly adds the rotation clamping algorithm and vertical projection on the basis of the drop water algorithm. It can not only solve the problem of inclination but also successfully divide the adhesive characters. For the complex design of NetEase CAPTCA, it mainly combines three algorithms: connected domain segmentation, vertical projection and drip segmentation, and makes use of their respective segmentation characteristics. The characters were successfully separated from the picture step by step.
【學位授予單位】：南京理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TP309
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