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图学学报

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一种古建墙壁受污题记文字图像边缘提取方法

  

  • 出版日期:2015-10-30 发布日期:2015-11-05

An Edge Extraction Method for Polluted Text Image of Ancient Inscription Wall

  • Online:2015-10-30 Published:2015-11-05

摘要: 针对古建墙壁题记文字图像受污染影响而边缘提取不完整、易产生伪边缘和不连续
边缘等问题,提出了一种受污题记文字边缘提取的方法。首先,对文字图像进行全变分去噪和多
尺度视网膜算法明暗增强预处理;然后构造阴影-遮挡准不变模型滤除污染和背景产生的伪边缘,
并用Gabor 滤波器对其进行空间平均,建立颜色结构张量,结合Canny 算法进行边缘提取;最后,
通过形态学方法滤除图像中存在的小面积边缘,并做区域连通处理,得到题记文字边缘图像。实
验结果表明,相比传统的Canny 算法和Sobel 算法,该方法有效地克服了污垢和背景造成的伪边
缘和不连续边缘,很好地提取出了完整的题记文字边缘,在边缘品质EQ 等客观指标上有较明显
提升。

关键词: 题记文字, 伪边缘, 全变分, 颜色结构张量

Abstract: On the issue that inscription text image of the ancient wall is contaminated leading to its edge
extraction is not complete, easy to produce false edge and discontinuous margin, this paper proposes a
novel method of edge extraction from polluted inscription text. Firstly, text image for total variation
denoising and multi-scale retinal algorithm shading to enhance preprocessing is used. Then construct a
shadow-blocking quasi-invariant model filtering out pollution and pseudo-edge generated by
background. Meanwhile, use Gabor filter to do spatial averaging and establish color structure tensor
combined with Canny algorithm to do edge detection. Finally, filter small area edge existing in the
image by morphological method and do the regional connectivity to obtain the edge inscription text
image. The results show that, compared to traditional Canny algorithm and morphological method, this
method effectively overcomes the false edge and discontinuous edge caused by dirt and background
which makes good extraction of edge inscription from the full text and a more objective indicators such
that edge quality has improved significantly.

Key words: inscription text, false edge, total variation, color structure tensor