Character Recognition of English Alphabets and Numerals

• Main Authors: CHENG, TAI-MING, 鄭泰銘
• Other Authors: Hsi-Jian Lee
• Format: Others
• Language: en_US
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/57406353303681744862

碩士 === 國立交通大學 === 資訊工程系 === 87 === In this thesis, we design a procedure for recognizing single text lines. In certain applications, single text lines are to be recognized without any whole-document information. This procedure consists of three parts: pre-processing, character recognition kernel, and post-processing. In the first phase, the skewing angle and italicness of the binarized image of a single text line are detected. After all connected components being extracted and proper combination/deletion, the vertical positions of components are shifted. Images are smoothed then. The components are to be recognized and, if necessary, segmented, using a dual-kernel according yto whether it is an italic text line or a roman one. Touching charcters are segmented using branch-and-bound tree traversal. Finally, vertical position information is used to post-process the recognition results. Some impossibilities are rejected and the correct class is eventually promoted to the first candidate. An approach to determining space characters using the profile is introduced. Characters that have the same shape in capital and lower case are justified according to their heights. In our experiments, we tested 646 text lines cut from English business name cards. The accuracy of skewing-angle detection was 99.23%. The accuracy of italicness detection was 100%. 93.18% of touching characters were correctly segmented. The character recognition rates for correctly segmented or un-touched roman and italic characters were 99.07 and 98.53 respectively.