视频中遮挡情况下目标的跟踪*

提出了一种基于概率外观模型和Condensation的跟踪方法.该方法通过分析目标前景MBB重叠关系检测遮挡的产生和解除,在目标未遮挡时建立并更新目标的概率外观模型.当遮挡发生后,利用目标共面条件确定目标前后关系,通过合并目标模型计算系统观测似然度概率.算法统一在Condensation框架下进行有遮挡和无遮挡的跟踪.实验证明了该方法的有效性.     

Appearance-based recognition of 3-D objects by cluttered background and occlusions

In this article we present a new appearance-based approach for the classification and the localization of 3-D objects in complex scenes. A main problem for object recognition is that the size and the appearance of the objects in the image vary for 3-D transformations. For this reason, we model the region of the object in the image as well as the object features themselves as functions of these transformations. We integrate the model into a statistical framework, and so we can deal with noise and illumination changes. To handle heterogeneous background and occlusions, we introduce a background model and an assignment function. Thus, the object recognition system becomes robust, and a reliable distinction, which features belong to the object and which to the background, is possible. Experiments on three large data sets that contain rotations orthogonal to the image plane and scaling with together more than 100 000 images show that the approach is well suited for this task.     

基于视频序列的双背景建模算法

在研究传统码本和滑动平均背景建模算法的基础上提出了一种基于视频序列的双背景建模算法, 并利用统计的方法提出了一种基于HSV特征的背景更新方法, 有效滤除了噪声点, 解决了光线突变下背景更新的问题。实验表明该算法对光照突变鲁棒性强, 响应速度快, 适合实时图像处理。     

Fast matching of large point sets under occlusions

The problem of isometric point-pattern matching can be modeled as inference in small tree-width graphical models whose embeddings in the plane are said to be ‘globally rigid’. Although such graphical models lead to efficient and exact solutions, they cannot generally handle occlusions, as even a single missing point may ‘break’ the rigidity of the graph in question. In addition, such models can efficiently handle point sets of only moderate size. In this paper, we propose a new graphical model that is not only adapted to handle occlusions but is much faster than previous approaches for solving the isometric point-pattern matching problem. We can match point-patterns with thousands of points in a few seconds.     

A temporal-spatial background modeling of dynamic scenes

Moving object detection in dynamic scenes is a basic task in a surveillance system for sensor data collection. In this paper, we present a powerful background subtraction algorithm called Gaussian-kernel density estimator (G-KDE) that improves the accuracy and reduces the computational load. The main innovation is that we divide the changes of background into continuous and stable changes to deal with dynamic scenes and moving objects that first merge into the background, and separately model background using both KDE model and Gaussian models. To get a temporal-spatial background model, the sample selection is based on the concept of region average at the update stage. In the detection stage, neighborhood information content (NIC) is implemented which suppresses the false detection due to small and un-modeled movements in the scene. The experimental results which are generated on three separate sequences indicate that this method is well suited for precise detection of moving objects in complex scenes and it can be efficiently used in various detection systems.     

液晶显示器斑痕缺陷高质量背景建模

针对目前液晶显示器斑痕(LCD-Mura)缺陷背景抑制检测中重建的背景存在引入性噪声干扰和目标缺损的问题,提出一种基于奇异值分解(SVD)和最大熵的缺陷图像背景建模方法:通过SVD图像像素矩阵,求得奇异值序列;借助矩阵范式推导出图像分量与奇异值的对应关系,进而以图像各分量奇异值所占比率计算各分量的熵值,以此利用最大熵确定重建背景的有效奇异值;再由矩阵重构得到背景,并进一步提出关于背景重建效果评价的一般方法。相比双三次B样条曲线拟合方法,该方法将区域Mura的对比度最少提升0.59倍,提升线Mura对比度最多达到7.71倍;相比离散余弦变换(DCT)方法,该方法将点Mura的噪声最少降低33.8%,将线Mura噪声降低76.76%。仿真结果表明,该模型具有低噪、低损和高亮的优点,能够更为准确地构建出缺陷图像的背景信息。     

背景模型的建立及保持方法比较

文章首先总结了一些背景的建模方法,并对这些方法进行了分类和比较,接着总结和比较了背景模型保持的方法,最后介绍了背景模型保持的一些原则。     

Case-based background modeling: associative background database towards low-cost and high-performance change detection

Background modeling and subtraction is an essential task in video surveillance applications. Many researchers have discussed about an improvement of performance of a background model, and a reduction of memory usage or computational cost. To adapt to background changes, a background model has been enhanced by introducing various information including a spatial consistency, a temporal tendency, etc. with a large memory allocation. Meanwhile, an approach to reduce a memory cost cannot provide better accuracy of a background subtraction. To tackle the trade-off problem, this paper proposes a novel framework named “case-based background modeling”. The characteristics of the proposed method are (1) a background model is created, or removed when necessary, (2) case-by-case model sharing by some of the pixels, (3) pixel features are divided into two groups, one for model selection and the other for modeling. These approaches realize a low-cost and high accurate background model. The memory usage and the computational cost could be reduced by half of a traditional method and the accuracy was superior to the method.     

Dynamic background modeling using deep learning autoencoder network

Multimedia Tools and Applications - Background modeling is a major prerequisite for a variety of multimedia applications like video surveillance, traffic monitoring, etc. Numerous approaches have...     

基于YCbCr的自适应混合高斯模型背景建模

混合高斯模型是最常用的背景建模方法之一,但是它的精确度是以耗时为代价的,且它在RGB颜色空间进行背景建模时,对噪声的处理效果一般。因此,对混合高斯模型进行改进,提出了一种基于YCbCr的自适应混合高斯模型背景建模方法。首先,将建模颜色空间从RGB转换到YCbCr;然后,采用自适应选择策略来确定混合高斯模型的高斯成分个数;最后,将高斯成分按照关键字的值进行排序,以确定背景模型。将提出的建模方法应用于运动目标检测,实验结果表明,提出的方法与混合高斯模型背景建模相比,运动目标检测的检测结果更准确,耗时更少。     

一种快速核密度估计背景建模方法

针对核密度估计背景建模方法运算量大难以实时应用的问题,提出了一种基于背景直方图分布的快速核密度估计背景建模方法。选用三角核函数进行核密度估计,根据三角核带宽函数的截断效应,引入背景分布的直方图完成快速背景建模,在保证目标检测准确性的同时提高运算速度。测试实验结果验证了算法能够满足监控系统的实时性要求。     

Kalman滤波器对混合高斯背景建模的改进

在目前的计算机视觉应用中,从视频序列中提取出运动目标是一个研究热点。针对传统方法在复杂多变环境下不能很好地检测出运动目标的问题,提出了一种基于Kalman滤波理论的改进混合高斯背景建模方法。利用Kalman滤波器的时域递归低通滤波特点,对混合高斯背景值进行了校正,同时对混合高斯背景更新方法进行了改进,与传统的混合高斯背景建模相比,该方法较好地消除了背景光照剧烈变化时误将背景检测为前景的现象,同时也能较好地消除背景噪声,提高了系统的可靠性和鲁棒性。     

基于光流优化的堆叠Unet背景建模神经网络

针对现有背景建模算法难以处理复杂前景及间歇性运动前景的问题,提出了一种基于非监督学习的背景建模算法（改进的BM-Unet算法）。该算法结合光流法和Pearson相关系数在视频帧上提取背景关注区域,以此优化网络训练集和损失函数,从而有效提高了该算法在复杂前景情况和前景停留情况下的适应性;在此基础上,为进一步提高背景生成的精确度,又提出了一种堆叠Unet网络架构BM-SUnet（background modelling stacked Unet）。在SBMnet数据集上与现有算法在可视化效果和评估参数两方面的比较结果表明,所提算法在复杂前景和间歇运动前景情况下建模准确性好且鲁棒性高的结论。     

区域颜色属性空间直方图背景建模

目的 为了能在光照变化、动态背景干扰这一类复杂场景中实时、准确地分割出运动前景,针对传统的基于颜色特征和基于像素的方法的不足,提出一种在颜色属性空间进行区域直方图建模的运动目标检测方法。方法 首先将RGB颜色空间映射到更为稳健的低维颜色属性空间,以颜色属性为特征在像素的局部范围内建立直方图,同时记录直方图每一个分区中像素的空间信息,使用K个空间直方图构成每个像素的背景模型,每个直方图根据其匹配度赋予不同的权重。降维的颜色属性提高了模型的鲁棒性和检测的时效性,空间直方图引入的位置信息提高了背景模型的准确性。然后通过学习率α_b和α_ω来控制各模型直方图及其权重的更新,以提高模型的适应性。在标准测试数据集的所有视频序列中进行了实验,通过分析综合性能指标（F1）及平均假阳性（FN）曲线,确定了算法中涉及参数的合理取值范围。结果 对实验结果定性和定量的分析表明,本文方法能够得到良好的前景检测效果,尤其在多模态场景和光线变化的复杂场景中能显著提高检测性能。各类场景的平均综合性能指标（average F1）相比性能突出的方法ViBe、LOBSTER（local binary similarity segmenter）和DECOLOR（detecting contiguous outliers in the low-rank representation）分别提高了0.65%、3.86%和3.9%,并通过GPU并行加速实现运动目标的实时检测。结论 在复杂视频环境下的运动目标检测中,相比已有方法,本文方法能够更为准确地分割出运动前景,是一种实时、有效的检测方法,具有一定的实用价值。     

一种新型移动物体检测及背景建模系统

帧差法和背景减除法是目前应用较广的移动物体检测方法。针对背景建模中经常出现拖尾现象,结合帧差法提出了一种新的移动物体检测系统,并就该系统的可扩展性进行了深入分析,提出了一种实时帧保存算法。实验结果表明,该系统可以很好地抑制拖尾效应,并为其他算法在该系统上的应用提供了更好的基础条件。     

Universal background modeling for acoustic surveillance of urban traffic

Traffic congestion in modern cities is an increasing problem having significant consequences in our daily lives. This work proposes a non-intrusive, passive monitoring framework based on the acoustic modality which can be used either autonomously or as a part of a multimodal system and provide valuable information to an intelligent transportation system. We consider a large number of audio classes which are typically encountered in urban areas. We introduce a combination of a powerful audio representation mechanism based on time, frequency and wavelet domain features with universal background modeling which leads to higher recognition accuracies and detection rates (in terms of false alarm and miss probability rates) with respect to commonly employed methodologies. The basic advantage of a class-specific model derived using the universal background modeling logic is its tolerance to data which belong to other sound classes. Another important feature of the proposed system is its ability to detect crash incidents, which apart from their catastrophic impact on human life and property, have negative consequences on the traffic flow. Our experiments are based on the concurrent usage of professional sound effect collections which include audio recordings of high quality. We thoroughly examine the performance of the proposed system on isolated sound events as well as continuous audio streams using confusion matrices and detection error trade-off curves.     

Non-parametric statistical background modeling for efficient foreground region detection

Most methods for foreground region detection in videos are challenged by the presence of quasi-stationary backgrounds—flickering monitors, waving tree branches, moving water surfaces or rain. Additional difficulties are caused by camera shake or by the presence of moving objects in every image. The contribution of this paper is to propose a scene-independent and non-parametric modeling technique which covers most of the above scenarios. First, an adaptive statistical method, called adaptive kernel density estimation (AKDE), is proposed as a base-line system that addresses the scene dependence issue. After investigating its performance we introduce a novel general statistical technique, called recursive modeling (RM). The RM overcomes the weaknesses of the AKDE in modeling slow changes in the background. The performance of the RM is evaluated asymptotically and compared with the base-line system (AKDE). A wide range of quantitative and qualitative experiments is performed to compare the proposed RM with the base-line system and existing algorithms. Finally, a comparison of various background modeling systems is presented as well as a discussion on the suitability of each technique for different scenarios.     

基于Codebook背景建模的视频行人检测

针对视频序列,Codebook背景建模算法能检测出其中的运动物体,但却无法识别行人.而大部分基于支持向量机(SVM)训练的行人分类器,需要通过滑动窗口遍历图像检测行人.为加快行人检测的速度,提出将传统的行人分类器融入到Codebook背景建模算法中,通过背景建模算法为行人检测提供候选区域,减少搜索范围,降低了行人误检率;并根据行人的特点,构建临时块模型定期将满足条件的前景区域更新到背景模型中,解决了Codebook背景建模算法不能应对光照突变的问题.实验结果表明:所提算法能应对光照突变所带来的干扰,实现视频行人实时检测.     

复杂背景下圆形物体分割算法

对如何从复杂的工业图像中准确提取圆形目标进行了研究。阐述了传统分割方法应用于复杂图像中提取圆形目标的局限性,提出了基于双阈值结合数学形态学运算的分割算法。首先分别根据两个阈值进行分割得到两幅二值图像,然后根据目标是圆形以及其大致位置等先验知识分别对两幅图进行腐蚀,开启,闭合等数学形态学运算,将高阈值分割得到的图像中的边界信息叠加到低阈值分割得到的图像中,实现对复杂背景图像中圆形物体的准确分割与提取,解决了复杂背景图像中物体识别率低的问题。实验结果表明本方法对复杂背景的图像预处理是有效的。