Multiple object tracking (MOT) in urban traffic aims to produce the trajectories of the different road users that move across the field of view with different directions and speeds and that can have varying appearances and sizes. Occlusions and interactions among the different objects are expected and common due to the nature of urban road traffic. In this work, a tracking framework employing classification label information from a deep learning detection approach is used for associating the different objects, in addition to object position and appearances. We want to investigate the performance of a modern multiclass object detector for the MOT task in traffic scenes. Results show that the object labels improve tracking performance, but that the output of object detectors are not always reliable.
MOT in urban traffic scenes was previously studied in @cite_13 , where the use of background subtraction is proposed for detecting the objects of interest followed by updating the object model with a state machine that uses feature points and spatial information. In fact, most previous work in MOT uses background subtraction or optical flow to detect the objects. The reason is that historically, methods based on pre-trained bounding box detectors are difficult to apply to road user tracking scenarios because it is difficult to design a detector that can detect and classify every possible type of road user from various viewpoints. However, recent progress in deep learning @cite_4 @cite_11 make this avenue now possible and worth investigating.
@cite_13 @cite_4 @cite_11
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Because of the large variability of road user appearance in an urban setting, it is very challenging to track all of them with the purpose of obtaining precise and reliable trajectories. However, obtaining the trajectories of the various road users is very useful for many transportation applications. It is particularly essential for any task that requires higher level behavior interpretation, including new safety diagnosis methods that rely on the observation of road user interactions without a collision and therefore do not require waiting for collisions to happen. In this paper, we propose a tracking method that has been specifically designed to track the various road users that may be encountered in an urban environment. Since road users have very diverse shapes and appearances, our proposed method starts from background subtraction to extract the potential a priori unknown road users. Each of these road users is then tracked using a collection of keypoints inside the detected foreground regions, which allows the interpolation of object locations even during object merges or occlusions. A finite state machine handles fragmentation, splitting, and merging of the road users to correct and improve the resulting object trajectories. The proposed tracker was tested on several urban intersection videos and is shown to outperform an existing reference tracker used in transportation research. We present region-based, fully convolutional networks for accurate and efficient object detection. In contrast to previous region-based detectors such as Fast Faster R-CNN that apply a costly per-region subnetwork hundreds of times, our region-based detector is fully convolutional with almost all computation shared on the entire image. To achieve this goal, we propose position-sensitive score maps to address a dilemma between translation-invariance in image classification and translation-variance in object detection. Our method can thus naturally adopt fully convolutional image classifier backbones, such as the latest Residual Networks (ResNets), for object detection. We show competitive results on the PASCAL VOC datasets (e.g., 83.6 mAP on the 2007 set) with the 101-layer ResNet. Meanwhile, our result is achieved at a test-time speed of 170ms per image, 2.5-20x faster than the Faster R-CNN counterpart. Code is made publicly available at: this https URL We present YOLO, a new approach to object detection. Prior work on object detection repurposes classifiers to perform detection. Instead, we frame object detection as a regression problem to spatially separated bounding boxes and associated class probabilities. A single neural network predicts bounding boxes and class probabilities directly from full images in one evaluation. Since the whole detection pipeline is a single network, it can be optimized end-to-end directly on detection performance. Our unified architecture is extremely fast. Our base YOLO model processes images in real-time at 45 frames per second. A smaller version of the network, Fast YOLO, processes an astounding 155 frames per second while still achieving double the mAP of other real-time detectors. Compared to state-of-the-art detection systems, YOLO makes more localization errors but is less likely to predict false positives on background. Finally, YOLO learns very general representations of objects. It outperforms other detection methods, including DPM and R-CNN, when generalizing from natural images to other domains like artwork.