基于色彩空间的最大稳定极值区域的自然场景文本检测

针对传统的最大稳定极值区域（MSER）方法无法很好地提取低对比度图像文本区域的问题，提出一种新的基于边缘增强的场景文本检测方法。首先，通过方向梯度值（HOG）有效地改进MSER方法，增强MSER方法对低对比度图像的鲁棒性，并在色彩空间分别求取最大稳定极值区域；其次，利用贝叶斯模型进行分类，主要采用笔画宽度、边缘梯度方向、拐角点三个平移旋转不变性特征剔除非字符区域；最后，利用字符的几何特性将字符整合成文本行，在公共数据集国际分析与文档识别（ICDAR）2003和ICDAR 2013评估了算法性能。实验结果表明，基于色彩空间的边缘增强的MSER方法能够解决背景复杂和不能从对比度低的场景图像中正确提取文本区域的问题。基于贝叶斯模型的分类方法在小样本的情况下能够更好地筛选字符，实现较高的召回率。相比传统的MSER进行文本检测的方法，所提方法提高了系统的检测率和实时性。

Natural scene text detection based on maximally stable extremal region in color space

To solve the problem that the text regions can not be extracted well in low contrast images by traditional Maximally Stable Extremal Regions (MSER) method, a novel scene text detection method based on edge enhancement was proposed. Firstly, the MSER method was effectively improved by Histogram of Oriented Gradients (HOG), the robustness of MSER method was enhanced to low contrast images and MSER was applied in color space. Secondly, the Bayesian model was used for the classification of characters, three features with translation and rotation invariance including stroke width, edge gradient direction and inflexion point were used to delete non-character regions. Finally, the characters were grouped into text lines by geometric characteristics of characters. The proposed algorithm's performance on standard benchmarks, such as International Conference on Document Analysis and Recognition (ICDAR) 2003 and ICDAR 2013, was evaluated. The experimental results demonstrate that MSER based on edge enhancement in color space can correctly extract text regions from complex and low contrast images. The Bayesian model based classification method can detect characters from small sample set with high recall. Compared with traditional MSER based method of text detection, the proposed algorithm can improve the detection rate and real-time performance of the system.