基于轴对称窗口文字图像检测快速算法研究

研究了图像定位的问题,由于存在污渍干扰等影响图像定位,针对以往单一特征进行图像文字定位及识别的系统中容易受到各种环境因素干扰的缺陷,提出了一种利用轴对称窗口进行边缘检测的图像文字检测算法。首先将利用轴对称滑动窗口提取水平和竖直方向上的边缘特征,利用连通域确定初始的图像文字位置;通过对可能的图像文字区域进行颜色色调验证,区域内垂直方向直方图投影,从而确定最终的图像文字位置。由于利用多种特征综合检测图像文字进行仿真。仿真结果表明改进方法能准确检测出复杂场景下图像文字所在区域。     

Accurate video text detection through classification of low and high contrast images

Detection of both scene text and graphic text in video images is gaining popularity in the area of information retrieval for efficient indexing and understanding the video. In this paper, we explore a new idea of classifying low contrast and high contrast video images in order to detect accurate boundary of the text lines in video images. In this work, high contrast refers to sharpness while low contrast refers to dim intensity values in the video images. The method introduces heuristic rules based on combination of filters and edge analysis for the classification purpose. The heuristic rules are derived based on the fact that the number of Sobel edge components is more than the number of Canny edge components in the case of high contrast video images, and vice versa for low contrast video images. In order to demonstrate the use of this classification on video text detection, we implement a method based on Sobel edges and texture features for detecting text in video images. Experiments are conducted using video images containing both graphic text and scene text with different fonts, sizes, languages, backgrounds. The results show that the proposed method outperforms existing methods in terms of detection rate, false alarm rate, misdetection rate and inaccurate boundary rate.     

基于多帧图像的视频文字跟踪和分割算法

视频中文字的提取是视频语义理解和检索的重要信息来源．针对视频中的静止文字时间和空间上的冗余特性，以文字区域的边缘位图为特征对检测结果作精化，并提出了基于二分搜索法的快速文字跟踪算法，实现了对文字对象快速有效的定位．在分割阶段，除了采用传统的灰度融合图像进行文字区域增强方法，还结合边缘位图对文字区域进行进一步的背景过滤．实验表明，文字的检测精度和分割质量都有很大提高．     

一种基于Homogeneity的文本检测新方法

视频图像中的文本包含了丰富的语义层次上的内容描述信息，为基于语义的图像检索提供重要的索引信息资源．提出了一种基于Homogeneity和支持向量机（support vector machine）的视频图像中文本检测方法，首先将图像由空间域映射到Homogeneity域中，然后对映射到Homogeneity空间中的图像进行特征提取，利用SVM判别文本区域．实验表明此文本检测方法优于用基于边缘特征的文本检测方法．     

基于边缘检测的快速纸张检测方法

结合普通纸笔交互方式对纸张检测的实时性和鲁棒性的要求，提出了一种基于边缘检测的快速纸张检测方法。在边缘检测阶段，提出了跨层特征融合的快速纸张边缘检测方法。在HED主干网上添加线性瓶颈逆残差块和融入高效通道注意力的B-ECA块，大幅度减少了参数量，增加了显著特征的权重;分阶段融合各阶段各层特征，保留了更多的边缘特征;对高阶段特征上采样，并与低阶段特征进行跨层特征融合，解决了边缘模糊的问题。在自建的MPDS数据集上进行训练和测试，相较于HED方法，提出的纸张边缘检测方法在ODS和OIS指标上分别提高了8.1%和6.6%，检测速度由22.08 fps提高到了39.02 fps。在纸张提取阶段，提出了基于纸张结构约束的纸张提取方法。依次对纸张边缘进行基于非极大值抑制的边缘细化、直线检测与筛选、结构约束的纸张顶点提取，最终提取出只包含纸张的图像。实验结果表明，在各种复杂桌面环境及遮挡情况下，提出的纸张提取方法均可以快速、准确地提取完整的纸张图像，可以为普通纸笔交互方法提供交互基础。     

基于边缘信息和LH的视频文本自动检测

视频数据中的文本能提供重要的语义信息。针对视频中的文本检测问题,提出了用基于边缘信息和LH的方法检测视频帧文本所在的位置,方法简单,能快速地定位文本区域,且不受文本颜色、语种、文本字体大小的限制。检测和分割效果良好。     

基于颜色聚类和多帧融合的视频文字识别方法

提出一种基于颜色聚类和多帧融合的视频文字识别方法,首先,在视频文字检测模块,综合考虑了文字区域的两个显著特征:一致的颜色和密集的边缘,利用近邻传播聚类算法,根据图像中边缘颜色的复杂程度,自适应地把彩色边缘分解到若干边缘子图中去,使得在各个子图中检测文字区域更为准确.其次,在视频文字增强模块,基于文字笔画强度图过滤掉模糊的文字区域,并综合平均融合和最小值融合的优点,对在不同视频帧中检测到的、包含相同内容的文字区域进行融合,能够得到背景更为平滑、笔画更为清晰的文字区域图像.最后,在视频文字提取模块,通过自适应地选取具有较高文字对比度的颜色分量进行二值化,能够取得比现有方法更好的二值化结果;另一方面,基于图像中背景与文字的颜色差异,利用颜色聚类的方法去除噪声,能够有效地提高文字识别率.实验结果表明,该方法能够比现有方法取得更好的文字识别结果.     

基于边缘检测和特征融合的自然场景文本定位

文本定位作为文本识别的基础和前提,对图像深层信息的理解至关重要。针对自然场景下的文本定位受光照、复杂背景等因素影响较大的问题,提出了一种基于多方向边缘检测和自适应特征融合的自然场景文本定位方法。该方法首先将自然场景图像进行三通道八方向的边缘检测;然后 通过启发式规则 对得到的边缘图像进行过滤从而提取出备选文本域,进而对备选文本域进行自适应权值的HOG-LBP特征提取与融合;最后采用支持向量机进行特征分类学习,实现文本定位。实验结果表明,该方法能准确定位自然场景图片的文本区域,对光照和复杂背景具有较强的鲁棒性。     

CNN and Fuzzy Rules Based Text Detection and Recognition from Natural Scenes

In today’s real world, an important research part in image processing is scene text detection and recognition. Scene text can be in different languages, fonts, sizes, colours, orientations and structures. Moreover, the aspect ratios and layouts of a scene text may differ significantly. All these variations appear assignificant challenges for the detection and recognition algorithms that are considered for the text in natural scenes. In this paper, a new intelligent text detection and recognition method for detectingthe text from natural scenes and forrecognizing the text by applying the newly proposed Conditional Random Field-based fuzzy rules incorporated Convolutional Neural Network (CR-CNN) has been proposed. Moreover, we have recommended a new text detection method for detecting the exact text from the input natural scene images. For enhancing the presentation of the edge detection process, image pre-processing activities such as edge detection and color modeling have beenapplied in this work. In addition, we have generated new fuzzy rules for making effective decisions on the processes of text detection and recognition. The experiments have been directedusing the standard benchmark datasets such as the ICDAR 2003, the ICDAR 2011, the ICDAR 2005 and the SVT and have achieved better detection accuracy intext detection and recognition. By using these three datasets, five different experiments have been conducted for evaluating the proposed model. And also, we have compared the proposed system with the other classifiers such as the SVM, the MLP and the CNN. In these comparisons, the proposed model has achieved better classification accuracywhen compared with the other existing works.     

A new concentric-circle visualization of multi-dimensional data and its application in network security

With the rapid growth of networked data communications in size and complexity, network administrators today are facing more challenges to protect their networked computers and devices from all kinds of attacks. This paper proposes a new concentric-circle visualization method for visualizing multi-dimensional network data. This method can be used to identify the main features of network attacks, such as DDoS attack, by displaying their recognizable visual patterns. To reduce the edge overlaps and crossings, we arrange multiple axes displayed as concentric circles rather than the traditional parallel lines. In our method, we use polycurves to link values (vertexes) rather than polylines used in parallel coordinate approach. Some heuristics are applied in our new method in order to improve the readability of views. We discuss the advantages as well as the limitations of our new method. In comparison with the parallel coordinate visualization, our approach can reduce more than 15% of the edge overlaps and crossings. In the second stage of the method, we have further enhanced the readability of views by increasing the edge crossing angle. Finally, we introduce our prototype system: a visual interactive network scan detection system called CCScanViewer. It is based on our new visualization approach and the experiments have showed that the new approach is effective in detecting attack features from a variety of networking patterns, such as the features of network scans and DDoS attacks.     

图像文本识别中目标定位方法研究

目标定位是图像文本识别的关键步骤。为了增加检测的可靠性,依据文本区域存在丰富的一致性边缘这一特性,改进了传统的基于Sobel边缘检测与形态学运算结合的文本检测方法,在此基础上采取了轮廓跟踪以及与先验知识结合的算法而实现了精确定位。     

A robust arbitrary text detection system for natural scene images

Text detection in the real world images captured in unconstrained environment is an important yet challenging computer vision problem due to a great variety of appearances, cluttered background, and character orientations. In this paper, we present a robust system based on the concepts of Mutual Direction Symmetry (MDS), Mutual Magnitude Symmetry (MMS) and Gradient Vector Symmetry (GVS) properties to identify text pixel candidates regardless of any orientations including curves (e.g. circles, arc shaped) from natural scene images. The method works based on the fact that the text patterns in both Sobel and Canny edge maps of the input images exhibit a similar behavior. For each text pixel candidate, the method proposes to explore SIFT features to refine the text pixel candidates, which results in text representatives. Next an ellipse growing process is introduced based on a nearest neighbor criterion to extract the text components. The text is verified and restored based on text direction and spatial study of pixel distribution of components to filter out non-text components. The proposed method is evaluated on three benchmark datasets, namely, ICDAR2005 and ICDAR2011 for horizontal text evaluation, MSRA-TD500 for non-horizontal straight text evaluation and on our own dataset (CUTE80) that consists of 80 images for curved text evaluation to show its effectiveness and superiority over existing methods.     

基于蚁群优化算法的复杂背景图像文字检测方法

针对复杂背景图像中的文字检测问题,提出一种基于蚁群优化算法的复杂背景图像文字检测方法。该方法首先采用蚁群优化算法提取图像边缘;然后在边缘图像上提取特征,采取由粗到精多级检测、验证的策略进行文字检测。与基于Soble算子、Canny算子等方法的对比实验结果表明,所提出的基于蚁群优化算法的文字检测方法可有效地实现复杂背景图像中的文字检测。     

一种新的利用多帧结合检测视频标题文字的算法

视频中的标题文字通常在视频信息索引和检索中起到重要作用．提出了一种新的视频标题文字的检测算法．首先采用一种新的多帧结合技术来降低图像背景的复杂度,它基于时间序列对多帧图像进行最小(或最大)像素值搜索,搜索的具体方式由Sobel边缘图来决定．然后以块为单位来进行文字与非文字的分类,即用一扫描窗口对图像进行扫描,以Sobel边缘为特征,判断其是否为文字。一个2级的金字塔被用来检测不同大小的文字．最后,提出一种新的迭代的文字区域分解方法,它能够更精确地定位文字区域的边界．实验结果表明,这种文字检测算法能够取得很高的精度和召回率．     

基于LBP和FSVM的视频文字定位方法

提出一种基于局部二值模式(LBP)和模糊支持向量机(FSVM)的视频文字定位方法。利用边缘信息和形态学操作进行文字粗检测,采用投影直方图和启发式规则形成候选文字区域,提取LBP作为纹理特征,用FSVM对候选文字区域进行精确定位,生成最终的文字块。实验结果表明,该方法具有较好的视频文字定位能力且鲁棒性较强。     

An Improved Method for Edge Detection and Image Segmentation Using Fuzzy Cellular Automata

Image segmentation is one of the most important and challenging problems in image processing. The main purpose of image segmentation is to partition an image into a set of disjoint regions with uniform attributes. In this study, we propose an improved method for edge detection and image segmentation using fuzzy cellular automata. In the first stage, we introduce a new edge detection method based on fuzzy cellular automata, called the texture histogram, and empirically demonstrate the efficiency of the proposed method and its robustness in denoising images. In the second stage, we propose an edge detection algorithm by considering the mean values of the edges matrix. In this algorithm, we use four fuzzy rules instead of 32 fuzzy rules reported earlier in the literature. In the third and final stage, we use the local edge in the edge detection stage to more accurately accomplish image segmentation. We demonstrate that the proposed method produces better output images in comparison with the separate segmentation and edge detection methods studied in the literature. In addition, we show that the method proposed in this study is more flexible and efficient when noise is added to an image.     

Feed-forward content based image retrieval using adaptive tetrolet transforms

This paper proposes a new approach for content based image retrieval based on feed-forward architecture and Tetrolet transforms. The proposed method addresses the problems of accuracy and retrieval time of the retrieval system. The proposed retrieval system works in two phases: feature extraction and retrieval. The feature extraction phase extracts the texture, edge and color features in a sequence. The texture features are extracted using Tetrolet transform. This transform provides better texture analysis by considering the local geometry of the image. Edge orientation histogram is used for retrieving the edge feature while color histogram is used for extracting the color features. Further retrieval phase retrieves the images in the feed-forward manner. At each stage, the number of images for next stage is reduced by filtering out irrelevant images. The Euclidean distance is used to measure the distance between the query and database images at each stage. The experimental results on COREL- 1 K and CIFAR - 10 benchmark databases show that the proposed system performs better in terms of the accuracy and retrieval time in comparison to the state-of-the-art methods.     

Pedestrian detection for intelligent transportation systems combining AdaBoost algorithm and support vector machine

Pedestrians are the vulnerable participants in transportation system when crashes happen. It is important to detect pedestrian efficiently and accurately in many computer vision applications, such as intelligent transportation systems (ITSs) and safety driving assistant systems (SDASs). This paper proposes a two-stage pedestrian detection method based on machine vision. In the first stage, AdaBoost algorithm and cascading method are adopted to segment pedestrian candidates from image. To confirm whether each candidate is pedestrian or not, a second stage is needed to eliminate some false positives. In this stage, a pedestrian recognizing classifier is trained with support vector machine (SVM). The input features used for SVM training are extracted from both the sample gray images and edge images. Finally, the performance of the proposed pedestrian detection method is tested with real-world data. Results show that the performance is better than conventional single-stage classifier, such as AdaBoost based or SVM based classifier.     

Optical font recognition using typographical features

A new statistical approach based on global typographical features is proposed to the widely neglected problem of font recognition. It aims at the identification of the typeface, weight, slope and size of the text from an image block without any knowledge of the content of that text. The recognition is based on a multivariate Bayesian classifier and operates on a given set of known fonts. The effectiveness of the adopted approach has been experimented on a set of 280 fonts. Font recognition accuracies of about 97 percent were reached on high-quality images. In addition, rates higher than 99.9 percent were obtained for weight and slope detection. Experiments have also shown the system robustness to document language and text content and its sensitivity to text length     

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。