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52
Robust Fragments-based Tracking using the Integral Histogram
- In IEEE Conf. Computer Vision and Pattern Recognition (CVPR
, 2006
"... We present a novel algorithm (which we call “Frag-Track”) for tracking an object in a video sequence. The template object is represented by multiple image fragments or patches. The patches are arbitrary and are not based on an object model (in contrast with traditional use of modelbased parts e.g. l ..."
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Cited by 224 (0 self)
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We present a novel algorithm (which we call “Frag-Track”) for tracking an object in a video sequence. The template object is represented by multiple image fragments or patches. The patches are arbitrary and are not based on an object model (in contrast with traditional use of modelbased parts e.g. limbs and torso in human tracking). Every patch votes on the possible positions and scales of the object in the current frame, by comparing its histogram with the corresponding image patch histogram. We then minimize a robust statistic in order to combine the vote maps of the multiple patches. A key tool enabling the application of our algorithm to tracking is the integral histogram data structure [18]. Its use allows to extract histograms of multiple rectangular regions in the image in a very efficient manner. Our algorithm overcomes several difficulties which cannot be handled by traditional histogram-based algorithms [8, 6]. First, by robustly combining multiple patch votes, we are able to handle partial occlusions or pose change. Second, the geometric relations between the template patches allow us to take into account the spatial distribution of the pixel intensities- information which is lost in traditional histogram-based algorithms. Third, as noted by [18], tracking large targets has the same computational cost as tracking small targets. We present extensive experimental results on challenging sequences, which demonstrate the robust tracking achieved by our algorithm (even with the use of only gray-scale (noncolor) information). 1.
Effective appearance model and similarity measure for particle filtering and visual tracking
- In Proc. European Conf. Computer Vision
, 2006
"... Abstract. In this paper, we adaptively model the appearance of objects based on Mixture of Gaussians in a joint spatial-color space (the approach is called SMOG). We propose a new SMOG-based similarity measure. SMOG captures richer information than the general color histogram because it incorporates ..."
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Cited by 18 (1 self)
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Abstract. In this paper, we adaptively model the appearance of objects based on Mixture of Gaussians in a joint spatial-color space (the approach is called SMOG). We propose a new SMOG-based similarity measure. SMOG captures richer information than the general color histogram because it incorporates spatial layout in addition to color. This appearance model and the similarity measure are used in a framework of Bayesian probability for tracking natural objects. In the second part of the paper, we propose an Integral Gaussian Mixture (IGM) technique, as a fast way to extract the parameters of SMOG for target candidate. With IGM, the parameters of SMOG can be computed efficiently by using only simple arithmetic operations (addition, subtraction, division) and thus the computation is reduced to linear complexity. Experiments show that our method can successfully track objects despite changes in foreground appearance, clutter, occlusion, etc.; and that it outperforms several colorhistogram based methods. 1
Robust tracking with motion estimation and local Kernel-based color modeling
- IMAGE AND VISION COMPUTING
, 2006
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A Survey of Appearance Models in Visual Object Tracking
"... Visual object tracking is a significant computer vision task which can be applied to many domains such as visual surveillance, human computer interaction, and video compression. Despite extensive research on this topic, it still suffers from difficulties in handling complex object appearance changes ..."
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Cited by 16 (1 self)
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Visual object tracking is a significant computer vision task which can be applied to many domains such as visual surveillance, human computer interaction, and video compression. Despite extensive research on this topic, it still suffers from difficulties in handling complex object appearance changes caused by factors such as illumination variation, partial occlusion, shape deformation, and camera motion. Therefore, effective modeling of the 2D appearance of tracked objects is a key issue for the success of a visual tracker. In the literature, researchers have proposed a variety of 2D appearance models. To help readers swiftly learn the recent advances in 2D appearance models for visual object tracking, we contribute this survey, which provides a detailed review of the existing 2D appearance models. In particular, this survey takes a module-based architecture that enables readers to easily grasp the key points of visual object tracking. In this survey, we first decompose the problem of appearance modeling into two different processing stages: visual representation and statistical modeling. Then, different 2D appearance models are categorized and discussed with respect to their composition modules. Finally, we address several issues of interest as well as the remaining challenges for future research on this topic. The contributions of this survey are four-fold. First, we review the literature of visual representations according to their feature-construction mechanisms (i.e., local and global). Second, the existing statistical modeling schemes for tracking-bydetection are reviewed according to their model-construction mechanisms: generative, discriminative, and hybrid generativediscriminative. Third, each type of visual representations or statistical modeling techniques is analyzed and discussed from
Differential Tracking based on Spatial-Appearance Model (SAM)
- IN PROC. CVPR’06
, 2006
"... A fundamental issue in differential motion analysis is the compromise between the flexibility of the matching criterion for image regions and the ability of recovering the motion. Localized matching criteria, e.g., pixel-based SSD, may enable the recovery of all motion parameters, but it does not to ..."
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Cited by 14 (1 self)
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A fundamental issue in differential motion analysis is the compromise between the flexibility of the matching criterion for image regions and the ability of recovering the motion. Localized matching criteria, e.g., pixel-based SSD, may enable the recovery of all motion parameters, but it does not tolerate much appearance changes. On the other hand, global criteria, e.g., matching histograms, can accommodate dramatic appearance changes, but may be blind to some motion parameters, e.g., scaling and rotation. This paper presents a novel differential approach that integrates the advantages of both in a principled way based on a spatial-appearance model (SAM) that combines local appearances variations and global spatial structures. This model can capture a large variety of appearance variations that are attributed to the local non-rigidity. At the same time, this model enables efficient recovery of all motion parameters. A maximum likelihood matching criterion is defined and rigorous analytical results are obtained that lead to a closed form solution to motion tracking. Very encouraging results demonstrate the effectiveness and efficiency of the proposed method for tracking non-rigid objects that exhibit dramatic appearance deformations, large object scale changes and partial occlusions.
Scale and Orientation Adaptive Mean Shift Tracking
"... Abstract – A scale and orientation adaptive mean shift tracking (SOAMST) algorithm is proposed in this paper to address the problem of how to estimate the scale and orientation changes of the target under the mean shift tracking framework. In the original mean shift tracking algorithm, the position ..."
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Abstract – A scale and orientation adaptive mean shift tracking (SOAMST) algorithm is proposed in this paper to address the problem of how to estimate the scale and orientation changes of the target under the mean shift tracking framework. In the original mean shift tracking algorithm, the position of the target can be well estimated, while the scale and orientation changes can not be adaptively estimated. Considering that the weight image derived from the target model and the candidate model can represent the possibility that a pixel belongs to the target, we show that the original mean shift tracking algorithm can be derived using the zero th and the first order moments of the weight image. With the zero th order moment and the Bhattacharyya coefficient between the target model and candidate model, a simple and effective method is proposed to estimate the scale of target. Then an approach, which utilizes the estimated area and the second order center moment, is proposed to adaptively estimate the width, height and orientation changes of the target. Extensive experiments are performed to testify the proposed method and validate its robustness to the
Data clustering as an optimum-path forest problem with applications in image analysis
- INTERN. JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY (IJIST
, 2009
"... We propose an approach for data clustering based on optimum-path forest. The samples are taken as nodes of a graph, whose arcs are defined by an adjacency relation. The nodes are weighted by their probability density values (pdf) and a connectivity function is maximized, such that each maximum of t ..."
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Cited by 8 (0 self)
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We propose an approach for data clustering based on optimum-path forest. The samples are taken as nodes of a graph, whose arcs are defined by an adjacency relation. The nodes are weighted by their probability density values (pdf) and a connectivity function is maximized, such that each maximum of the pdf becomes root of an optimum-path tree (cluster), composed by samples "more strongly connected" to that maximum than to any other root. We discuss the advantages over other pdf-based approaches and present extensions to large datasets with results for interactive image segmentation and for fast, accurate, and automatic brain tissue classification in magnetic resonance (MR) images. We also include experimental comparisons with other clustering approaches. VC 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 50–68, 2009; Published online in Wiley
Mean shift tracking with random sampling
- Proc. BMVC 2005
, 2006
"... In this work, boosting the efficiency of Mean-Shift Tracking using random sampling is proposed. We obtained the surprising result that mean-shift tracking requires only very few samples. Our experiments demonstrate that robust tracking can be achieved with as few as even 5 random samples from the im ..."
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Cited by 7 (0 self)
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In this work, boosting the efficiency of Mean-Shift Tracking using random sampling is proposed. We obtained the surprising result that mean-shift tracking requires only very few samples. Our experiments demonstrate that robust tracking can be achieved with as few as even 5 random samples from the image of the object. As the computational complexity is considerably reduced and becomes independent of object size, the processor can be used to handle other processing tasks while tracking. It is demonstrated that random sampling significantly reduces the processing time by two orders of magnitude for typical object sizes. Additionally, with random sampling, we propose a new optimal on-line feature selection algorithm for object tracking which maximizes a similarity measure for the weights of the RGB channels. It selects the weights of the RGB channels which discriminate the object and the background the most using Steepest Descent. Moreover, the spatial distribution of pixels representing the object is estimated for spatial weighting. Arbitrary spatial weighting is incorporated into Mean-Shift Tracking to represent objects with arbitrary or changing shapes by picking up non-uniform random samples. Experimental results demonstrate that our tracker with online feature selection and arbitrary spatial weighting outperforms the original mean-shift tracker with improved computational efficiency and tracking accuracy. 1
Efficient subset selection via the kernelized Rényi distance
"... With improved sensors, the amount of data available in many vision problems has increased dramatically and allows the use of sophisticated learning algorithms to perform inference on the data. However, since these algorithms scale with data size, pruning the data is sometimes necessary. The pruning ..."
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Cited by 6 (5 self)
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With improved sensors, the amount of data available in many vision problems has increased dramatically and allows the use of sophisticated learning algorithms to perform inference on the data. However, since these algorithms scale with data size, pruning the data is sometimes necessary. The pruning procedure must be statistically valid and a representative subset of the data must be selected without introducing selection bias. Information theoretic measures have been used for sampling the data, retaining its original information content. We propose an efficient Rényi entropy based subset selection algorithm. The algorithm is first validated and then applied to two sample applications where machine learning and data pruning are used. In the first application, Gaussian process regression is used to learn object pose. Here it is shown that the algorithm combined with the subset selection is significantly more efficient. In the second application, our subset selection approach is used to replace vector quantization in a standard object recognition algorithm, and improvements are shown. 1.
Robust Mean Shift Tracking with Corrected Background-Weighted Histogram
"... Abstract: The background-weighted histogram (BWH) algorithm proposed in [2] attempts to reduce the interference of background in target localization in mean shift tracking. However, in this paper we prove that the weights assigned to pixels in the target candidate region by BWH are proportional to t ..."
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Cited by 6 (0 self)
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Abstract: The background-weighted histogram (BWH) algorithm proposed in [2] attempts to reduce the interference of background in target localization in mean shift tracking. However, in this paper we prove that the weights assigned to pixels in the target candidate region by BWH are proportional to those without background information, i.e. BWH does not introduce any new information because the mean shift iteration formula is invariant to the scale transformation of weights. We then propose a corrected BWH (CBWH) formula by transforming only the target model but not the target candidate model. The CBWH scheme can effectively reduce background’s interference in target localization. The experimental results show that CBWH can lead to faster convergence and more accurate localization than the usual target representation in mean shift tracking. Even if the target is not well initialized, the proposed algorithm can still robustly track the object, which is hard to achieve by the conventional target representation.
