Recently, Siamese network based trackers have received tremendous interest for their fast tracking speed and high performance. Despite the great success, this tracking framework still suffers from several limitations. First, it cannot properly handle large object rotation. Second, tracking gets easily distracted when the background contains salient objects. In this paper, we propose two simple yet effective mechanisms, namely angle estimation and spatial masking, to address these issues. The objective is to extract more representative features so that a better match can be obtained between the same object from different frames. The resulting tracker, named Siam-BM, not only significantly improves the tracking performance, but more importantly maintains the realtime capability. Evaluations on the VOT2017 dataset show that Siam-BM achieves an EAO of 0.335, which makes it the best-performing realtime tracker to date.
Apparently we are not the first who concerns transformation estimation in visual object tracking. In correlation filter based trackers, DSST @cite_12 and SAMF @cite_30 are early work that estimates the scale change of the tracked object. DSST @cite_12 does so by learning separate discriminative correlation filters for translation and scale estimation. SAMF @cite_30 uses a scale pyramid to search corresponding target scale. Recently, RAJSSC @cite_22 proposes to perform both scale and angle estimation in a unified correlation tracking framework by using the Log-Polar transformation. In SiamFC-based trackers, while the scale estimation has been considered in the original SiamFC tracker, angle estimation has not been considered before.
@cite_30 @cite_22 @cite_12
2238128272 2317058546 2617352822 1997121481
Boosted by large and standardized benchmark datasets, visual object tracking has made great progress in recent years and brought about many new trackers. Among these trackers, correlation filter based tracking schema exhibits impressive robustness and accuracy. In this work, we present a fully functional correlation filter based tracking algorithm which is able to simultaneously model target appearance changes from spatial displacements, scale variations, and rotation transformations. The proposed tracker first represents the exhaustive template searching in the joint scale and spatial space by a block-circulant matrix. Then, by transferring the target template from the Cartesian coordinate system to the Log-Polar coordinate system, the circulant structure is well preserved for the target even after whole orientation rotation. With these novel representation and transformation, object tracking is efficiently and effectively performed in the joint space with fast Fourier Transform. Experimental results on the VOT 2015 benchmark dataset demonstrate its superior performance over state-of-the-art tracking algorithms. Among increasingly complicated trackers in visual tracking area, recently proposed correlation filter based trackers have achieved appealing performance despite their great simplicity and superior speed. However, the filter input is a bounding box of fixed size, so they are not born with the adaptability to target’s scale and aspect ratio changes. Although scaleadaptive variants have been proposed, they are not flexible enough due to pre-defined scale sampling manners. Moreover, to the best of our knowledge, no correlation filter variant has been proposed to handle aspect ratio variation. To tackle this problem, this paper integrates the class-agnostic detection proposal method, which is widely adopted in object detection area, into a correlation filter tracker, and presents KCFDP tracker. The correlation filter part of KCFDP is based on KCF[2] with some modifications. We extend the HOG feature in KCF to a combination of HOG, intensity, and color naming by simply concatenating the three features, resulting in 42 feature channels. The model updating scheme in KCF, which is simple linear interpolation, is substituted with a more robust scheme presented in [1]. EdgeBoxes[4] is adopted to generate flexible detection proposals and enable the scale and aspect ratio adaptability of our tracker. It traverses the whole image in a sliding window manner, and scores every sampled bounding box according to the number of contours that are wholly enclosed. To accelerate EdgeBoxes and produce less unnecessary proposals, we set the minimum proposal area and aspect ratio range dynamically in sliding window sampling according to the current target size. In the tracking pipeline, KCF is firstly performed to estimate the preliminary target location ld . Within a patch zd extracted from current frame, KCF locates the target center according to the location of the maximum element in f : f(zd) = kxz d · α, (1) Advances in mathematical models and optimization introduce powerful tools for solving the visual object tracking problem, but this fundamental problem remains unsolved due to various challenges such as illumination variation, deformation and occlusion. Recent progress in correlation filter based models has provided an effective and efficient tracking solution. This type of trackers exploits the property of convolution theorem to significantly speed up their computational processes. However, their scheme of training correlation filters restricts them to use only a few negative examples to train their model, consequently lowers their performance. Therefore, in this paper, we propose to combine the fast calculation advantage of correlation filter with an online discriminative learning model, which can fully exploit the negative examples in the context around the target. The proposed tracker proceeds in a coarse-to-fine scheme: the proposed tracker will first employ a correlation filter to generate a coarse estimation of the location of the target, and then employ a translating model to refine its estimation and calculate the scale variation of the target via a scaling model. Both the translating model and the scaling model are formulated in the framework of our online discriminative model. Besides, we also propose an effective offline representation learning method to generate robust image feature for our correlation filter. Extensive experiments on the online Object Tracking Benchmark against the state-of-the-art methods validate the effectiveness of the proposed tracker. Robust scale estimation is a challenging problem in visual object tracking. Most existing methods fail to handle large scale variations in complex image sequences. This paper presents a novel approach for robust scale estimation in a tracking-by-detection framework. The proposed approach works by learning discriminative correlation filters based on a scale pyramid representation. We learn separate filters for translation and scale estimation, and show that this improves the performance compared to an exhaustive scale search. Our scale estimation approach is generic as it can be incorporated into any tracking method with no inherent scale estimation.Experiments are performed on 28 benchmark sequences with significant scale variations. Our results show that the proposed approach significantly improves the performance by 18.8 in median distance precision compared to our baseline. Finally, we provide both quantitative and qualitative comparison of our approach with state-of-the-art trackers in literature. The proposed method is shown to outperform the best existing tracker by 16.6 in median distance precision, while operating at real-time.