Abstract: The algorithm of exemplar-based image inpainting was introduced to the digital protection of Thangka image due to the advantage that can repair the broken structure and texture effectively at the same time. This algorithm is good at repairing the specific broken images of Thangka， but is not appropriate to other kinds of broken images. Hence, this paper proposed two aspects of improvement for the deficiencies of exemplar-based broken Thangka image inpainting: the improvement of computing method of confidence and the improvement of computing method of isophote intensity. The problem that optimum exemplar block is not exclusive has been solved. The experimental results show that the improved algorithm can not only get a satisfied inpainting result but also improve repairing efficiency.

Key words: Thangka, image inpainting, priority, confidence degree, optimum exemplar block

摘要： 基于样本块的修复算法由于能同时有效地修复图像的受损纹理和结构的优点被引入到唐卡图像的数字化保护中，而且它对特定破损唐卡图像修复效果良好，但是由于优先权计算和最佳样本块不唯一等问题的影响，算法对其他类唐卡图像修复效果不佳。针对此算法的不足，对信任度计算方法和等照线计算方法进行了改进，解决了最佳样本块不唯一的问题。实验结果证明，改进后的算法不仅能够得到令人满意的修复结果而且能够提高修复效率。

关键词: 唐卡, 图像修复, 优先权, 自信度, 最佳样本块