文档图像中书写线的检测与去除

采用快速的Hough变换检测文档图像中的书写线，从图像中抽取少量特征点，将其分成两个子集，每次从两个子集中各取一个上点计算变换窨内的对应参数，当变换空间的累加值达到预先设定的阈值就认为已成功书写线，使Hough变换的速度大大加快，具有很强的实用价值，根据书写线与字符笔画的位置关系去除书写线，对书写线和相交的区域依据书写线的宽度和相交情形确定不同的结构元素，进行数学形态学的开运算，去除书写线的同时，较好地保持了字符笔画，实验结果表明，对信封图像上书写线的检测和去除有满意的处理效果。

DETECTION AND REMOVAL OF BASE LINES FROM DOCUMENT IMAGES

Fast Hough transform is utilized to detect base lines from document images. Feature points taken from the image are divided into two subsets, from which two feature points are selected respectively to compute parameters in Hough space. A threshold is set such that any bin exceeding the threshold means the evidence of the reference line and the detection will stop. The proposed Hough transform can be implemented at fast speed with practical value. The base line is removed by using mathematical morphology operation, while the structural element is decided according to the width of the base line and the intersectional stroke. Character strokes are protected while the base line is removed. Experimental results with envelope images show that the presented method can detect and remove base lines effectively.