Improvement on centroid detection method for text document watermarking
文本文档水印质心检测方法的改进

An improvement on centroid detection method invented by Brassil et al was presented.The improved method constructs a centroid series which were convergent in probability to centroid of initial text line using both initial profile and reproduced profile of text line.Experimental result shows that the new approach may half down the probability of detection error in the case of short text lines in comparison with the Brassil' method.The conclusion suggests that line-shift coding would not be subject to text line length again,either long lines or short lines are all used to embed watermark,and the watermark capacity is increased.