基于颜色和边缘信息融合的背景建模方法

提出一种颜色和边缘信息融合的背景建模方法。在像素级利用基于颜色特征的背景差方法,将像素分类为前景像素和背景像素。给出一种新的基于边缘特征的背景差方法,将边缘分类为前景边缘和背景边缘。将前景像素聚类为不同的目标区域,利用前景边缘信息识别出真实运动目标和虚假运动目标。实验表明,该方法可以有效地去除由于局部突然光照变化和背景静止目标的移动造成的虚假运动目标,提高运动目标检测的精确率。     

Self-organizing background subtraction using color and depth data

Background subtraction from color and depth data is a fundamental task for video surveillance applications that use data acquired by RGBD sensors. We present a method that adopts a self-organizing neural background model previously adopted for RGB videos to model the color and depth background separately. The resulting color and depth detection masks are combined to guide the selective model update procedure and to achieve the final result. Extensive experimental results and comparisons with several state-of-the-art methods on a publicly available dataset show that the exploitation of depth information allows achieving much higher performance than just using color, accurately handling color and depth background maintenance challenges.

     

Contour extraction of moving objects in complex outdoor scenes

This paper presents a new approach to the extraction of the contour of a moving object. The method is based on the fusion of a motion segmentation technique using image subtraction and a color segmentation technique based on the split-and-merge paradigm and edge information obtained from using the Canny edge detector. The advantages of this method are the following: it can detect large moving objects, the background can be arbitrarily complicated and contain many nonmoving objects, and it requires only three image frames that need not be consecutive provided that the moving object is entirely contained in the three frames. It is assumed that there is only one moving object in the image and the objects are not blurred by their motion so that the edges in the image are sharp. The method was applied to road images containing a moving vehicle, and the results show that the contour was correctly extracted in 18 of the 20 cases. We show that this contour extraction method gives good results for other types of moving objects as well. We also describe how the extracted contour can be used to classify a given vehicle into five generic categories. In this study, 19 out of the 20 vehicles were correctly classified. These results demonstrate that integration of multiple cues obtained from relatively simple image analysis techniques leads to a robust extraction of the object of interest in complex outdoor scenes.Research supported by a grant from the U.S. Department of Transportation through the Great Lakes Center for Truck Transportation Research and by a grant from the National Science Foundation (CDA-8806599).     

联合聚焦度和传播机制的光场图像显著性检测

目的 图像显著性检测方法对前景与背景颜色、纹理相似或背景杂乱的场景,存在背景难抑制、检测对象不完整、边缘模糊以及方块效应等问题。光场图像具有重聚焦能力,能提供聚焦度线索,有效区分图像前景和背景区域,从而提高显著性检测的精度。因此,提出一种基于聚焦度和传播机制的光场图像显著性检测方法。方法 使用高斯滤波器对焦堆栈图像的聚焦度信息进行衡量,确定前景图像和背景图像。利用背景图像的聚焦度信息和空间位置构建前/背景概率函数,并引导光场图像特征进行显著性检测,以提高显著图的准确率。另外,充分利用邻近超像素的空间一致性,采用基于K近邻法（K-nearest neighbor,K-NN）的图模型显著性传播机制进一步优化显著图,均匀地突出整个显著区域,从而得到更加精确的显著图。结果 在光场图像基准数据集上进行显著性检测实验,对比3种主流的传统光场图像显著性检测方法及两种深度学习方法,本文方法生成的显著图可以有效抑制背景区域,均匀地突出整个显著对象,边缘也更加清晰,更符合人眼视觉感知。查准率达到85.16%,高于对比方法,F度量（F-measure）和平均绝对误差（mean absolute error,MAE）分别为72.79%和13.49%,优于传统的光场图像显著性检测方法。结论 本文基于聚焦度和传播机制提出的光场图像显著性模型,在前/背景相似或杂乱背景的场景中可以均匀地突出显著区域,更好地抑制背景区域。     

Automatic Real-Time Video Matting Using Time-of-Flight Camera and Multichannel Poisson Equations

This paper presents an automatic real-time video matting system. The proposed system consists of two novel components. In order to automatically generate trimaps for live videos, we advocate a Time-of-Flight (TOF) camera-based approach to video bilayer segmentation. Our algorithm combines color and depth cues in a probabilistic fusion framework. The scene depth information returned by the TOF camera is less sensitive to environment changes, which makes our method robust to illumination variation, dynamic background and camera motion. For the second step, we perform alpha matting based on the segmentation result. Our matting algorithm uses a set of novel Poisson equations that are derived for handling multichannel color vectors, as well as the depth information captured. Real-time processing speed is achieved through optimizing the algorithm for parallel processing on graphics hardware. We demonstrate the effectiveness of our matting system on an extensive set of experimental results.     

联合多特征的自动CamShift跟踪算法

针对CamShift跟踪算法仅采用颜色作特征,易发生跟踪错误等问题,提出了一种基于特征融合的算法。采用改进的背景差分法自动检测目标,目标模型联合了颜色和梯度方向特征,并对特征的可信度进行加权处理,有效解决了CamShift算法在有颜色相近的干扰目标存在情况下跟踪可能失效的问题。实验表明,该算法提高了跟踪的准确性和稳健性。     

基于统计背景模型的运动目标检测方法

运动目标检测是计算机视觉、视频处理等应用领域的重要研究内容。其中减背景技术是一种常用方法。在减背景方法中，背景模型的提取、更新、背景扰动、外界光照条件变化、阴影检测等是必须要考虑的问题。提出了一种有效的运动目标检测方法，较好地解决了以上问题，首先利用统计的方法得到背景模型，并实时地对背景模型更新．以适应光线变化和场景本身的变化，用形态学方法和检测连通域面积进行后处理，消除噪声和背景扰动带来的影响，在HSV色度空间下检测阴影，得到准确的运动目标。实验结果表明，该方法是快速有效的。     

A fuzzy spatial coherence-based approach to background/foreground separation for moving object detection

The detection of moving objects from stationary cameras is usually approached by background subtraction, i.e. by constructing and maintaining an up-to-date model of the background and detecting moving objects as those that deviate from such a model. We adopt a previously proposed approach to background subtraction based on self-organization through artificial neural networks, that has been shown to well cope with several of the well known issues for background maintenance. Here, we propose a spatial coherence variant to such approach to enhance robustness against false detections and formulate a fuzzy model to deal with decision problems typically arising when crisp settings are involved. We show through experimental results and comparisons that higher accuracy values can be reached for color video sequences that represent typical situations critical for moving object detection.     

Visible and infrared image registration using trajectories and composite foreground images

The registration of images from multiple types of sensors (particularly infrared sensors and visible color sensors) is a step toward achieving multi-sensor fusion. This paper proposes a registration method using a novel error function. Registration of infrared and visible color images is performed by using the trajectories of moving objects obtained using background subtraction and simple tracking. The trajectory points are matched using a RANSAC-based algorithm and a novel registration criterion, which is based on the overlap of foreground pixels in composite foreground images. This criterion allows performing registration when there are few trajectories and gives more stable results. Our method was tested and its performance quantified using nine scenarios. It outperforms a related method only based on trajectory points in cases where there are few moving objects.     

基于RGB颜色空间的减背景运动目标检测

在计算机视觉领域中,运动目标检测与分割是一个基础而又关键的问题.减背景法是其中一个比较经典和常用的方法,其难点在于如何获取背景以及实现背景的自适应更新.针对该问?提出一种基于RGB颜色空间的运动目标检测算法,充分利用了图像序列在RGB空间中的变化特点,首先通过抽取帧图像进行背景重构,即对图像序列中每个像素点的RGB值进行排序后取中间值作为该点背景像素的RGB值;在此基础上引入学习率对背景进行自适应更新,然后在RGB空间中进行前景目标提取,最后利用数学形态学和连通性分析对结果进行后处理.实验结果表明,该算法快速有效、能够满足实时要求.     

Handling occlusions in video‐based augmented reality using depth information

Augmented Reality (AR) composes virtual objects with real scenes in a mixed environment where human–computer interaction has more semantic meanings. To seamlessly merge virtual objects with real scenes, correct occlusion handling is a significant challenge. We present an approach to separate occluded objects in multiple layers by utilizing depth, color, and neighborhood information. Scene depth is obtained by stereo cameras and two Gaussian local kernels are used to represent color, spatial smoothness. These three cues are intelligently fused in a probability framework, where the occlusion information can be safely estimated. We apply our method to handle occlusions in video‐based AR where virtual objects are simply overlapped on real scenes. Experiment results show the approach can correctly register virtual and real objects in different depth layers, and provide a spatial‐awareness interaction environment. Copyright © 2009 John Wiley & Sons, Ltd.     

多角度融合的RGB-D显著检测

显著检测是计算机视觉的重要组成部分,但大部分的显著检测工作着重于2D图像的分析,并不能很好地应用于RGB-D图片的显著检测。受互补的显著关系在2D图像检测中取得的优越效果的启发,并考虑RGB-D图像包含的深度特征,提出多角度融合的RGB-D显著检测方法。此方法主要包括三个部分,首先,构建颜色深度特征融合的图模型,为显著计算提供准确的相似度关系;其次,利用区域的紧密度进行全局和局部融合的显著计算,得到相对准确的初步显著图;最后,利用边界连接权重和流形排序进行背景和前景融合的显著优化,得到均匀平滑的最终显著图。在RGBD1000数据集上的实验对比显示,所提出的方法超越了当前流行的方法,表明多个角度互补关系的融合能够有效提高显著检测的准确率。     

一种新的道路交通背景提取算法及研究

基于视频的道路运动目标检测是智能交通系统的基础部分,目前最常用也最有效的运动目标检测方法是背景差分算法,其中背景提取是背景差分算法的关键一环。提出了一种新的背景提取算法——mode算法。定义了算法比较标准,并据此比较了mode算法以及一些目前流行的背景提取算法在不同车流量情况下的性能优劣。通过比较发现,在低车流量时,中值法提取的背景较好,mode算法次之;在高车流量时,用mode算法提取的背景最好。基于不同算法在不同环境下的性能不同,利用图像频域信息区分车流量大小,实现对背景提取算法的自适应选择,使得实际应用时的背景提取算法更具灵活性和针对性,也进一步提高了背景提取结果的准确度。     

一种基于目标分割的实时跟踪方法

为减少颜色相似背景在目标跟踪过程中对跟踪结果的影响,提出一种基于目标分割的实时跟踪方法。利用背景差分的方法进行目标分割,使用目标位置、大小及颜色的特征完成目标状态的更新,对连续帧之间的目标实施匹配跟踪,当2个目标重合分离时采用目标大小、颜色特征实现匹配。实验结果表明,该方法匹配跟踪速度较快、跟踪效果较好。     

一种新的基于统计的背景减除方法

提出了一种有效的彩色视频背景减除的新方法。首先对彩色视频采样得到图像序列,统计序列中各像素的RGB值并归类,用出现概率最高类的RGB均值来构建背景模型;然后根据颜色差异和亮度范围综合条件,结合形态学处理进行背景减除。实验结果表明,此法可以很好地克服灰度视频背景减除中很难识别与背景灰度相近目标的缺陷,同时比传统的彩色视频背景建模快速,且样本中允许运动目标存在。对背景减除的准确性和实时性有一定程度地改进。该文还针对光照和背景变化提出了一些有效的背景更新策略。     

Fast variational multi-view segmentation through backprojection of spatial constraints

We present a variational segmentation method which exploits color, edge and spatial information between an arbitrary number of views. In contrast to purely image based information like color and gradient, spatial consistency is a new cue for segmentation, which originates from the field of 3D reconstruction. We show that this cue can be easily integrated in a variational formulation and allows pixel-accurate segmentation, even for objects which are hard to segment. The use of inherently parallel algorithms and the implementation on modern GPUs allows us to apply this method to semi-supervised and completely automatic settings. On publicly available datasets we show that our method is faster and more accurate than the state of the art. The successful applications within a catadioptric measurement system and multi-view background subtraction shows its practical relevance.     

Depth incorporating with color improves salient object detection

Detecting salient objects in challenging images attracts increasing attention as many applications require more robust method to deal with complex images from the Internet. Prior methods produce poor saliency maps in challenging cases mainly due to the complex patterns in the background and internal color edges in the foreground. The former problem may introduce noises into saliency maps and the later forms the difficulty in determining object boundaries. Observing that depth map can supply layering information and more reliable boundary, we improve salient object detection by integrating two features: color information and depth information which are calculated from stereo images. The two features collaborate in a two-stage framework. In the object location stage, depth mainly helps to produce a noise-filtered salient patch, which indicates the location of the object. In the object boundary inference stage, boundary information is encoded in a graph using both depth and color information, and then we employ the random walk to infer more reliable boundaries and obtain the final saliency map. We also build a data set containing 100+ stereo pairs to test the effectiveness of our method. Experiments show that our depth-plus-color based method significantly improves salient object detection compared with previous color-based methods.     

一种适于公交乘客计数的自适应背景更新算法

在基于视频图像处理的乘客计数系统(APC)中,背景与前景目标的分割是运动目标检测的关键。针对公交车APC系统的特征,在背景差法的基础上,结合相邻帧差以及平均灰度差,提出了一种自适应背景更新算法,以此为基础,实现了视频图像序列中的运动目标检测。通过对公交车实验采集的视频图像进行处理,证明算法能够克服光线的变化及干扰物体的影响,有效地实现目标分割。     

Detecting moving objects, ghosts, and shadows in video streams

Background subtraction methods are widely exploited for moving object detection in videos in many applications, such as traffic monitoring, human motion capture, and video surveillance. How to correctly and efficiently model and update the background model and how to deal with shadows are two of the most distinguishing and challenging aspects of such approaches. The article proposes a general-purpose method that combines statistical assumptions with the object-level knowledge of moving objects, apparent objects (ghosts), and shadows acquired in the processing of the previous frames. Pixels belonging to moving objects, ghosts, and shadows are processed differently in order to supply an object-based selective update. The proposed approach exploits color information for both background subtraction and shadow detection to improve object segmentation and background update. The approach proves fast, flexible, and precise in terms of both pixel accuracy and reactivity to background changes.