一种基于车载图像的异常轨迹检测与预校正方法

A Method for Abnormal Trajectory Detection and Pre-Correction Based on Vehicle-Borne Images

  • 摘要: 众包是实现高精地图实时更新的必要途径,也是高精地图未来的应用形态。低成本众包设备使得众包轨迹数据普遍存在位置偏移和属性记录异常等情况,进而影响高精地图众包更新的精度。地图匹配算法可以根据轨迹与道路之间的时空特征将存在位置偏移的轨迹点垂直匹配到车辆行驶的道路上,但是平行于道路方向的较大位置偏移与异常的行驶角度仍会影响轨迹位置校正的精度。鉴于高精地图众包数据中的车载图像能够反映车辆的行驶环境与姿态变化,本研究借助计算机视觉技术和隐马尔可夫模型构建了异常轨迹数据的检测与预校正方法,以实现轨迹数据的异常角度校正和整体位置纠偏。本研究以武汉市为研究区域,以30条带有车载图像的轨迹数据为研究对象,通过综合实验验证了所提出的方法在提升众包轨迹数据质量方面的有效性,并通过将预校正方法与地图匹配算法结合进一步证明了数据质量提升能够有效提升轨迹位置校正的精度,为推动高精地图众包更新的应用落地提供了一定的技术支撑与方法参考。

     

    Abstract: Objectives: Trajectory data obtained from low-cost crowdsourcing devices often suffer from overall positional offsets and abnormal attribute recordings, failing to meet the accuracy requirements for high-definition map updates. Given that onboard images in crowdsourcing data can capture changes in the driving environment and vehicle orientation, this paper aims to explore correction methods for overall trajectory position offsets and abnormal driving angles based on continuous onboard images. Our goal is to provide high-quality trajectory data that enhances the accuracy of subsequent position correction methods. Methods: This study first employs structurefrom-motion technology to estimate the pose of the onboard camera, followed by the detection and correction of abnormal driving angles based on the estimated pose information. Next, the study identifies key trajectory points located at intersections and other critical locations using semantic information extracted from onboard images. The corrected angle values and hidden Markov model are then utilized to match these key trajectory points with nodes, enabling the detection and correction of overall trajectory position offsets. Finally, Wuhan city is selected as the research area, and 30 trajectory data accompanied by onboard images are used to validate the effectiveness of the proposed method. Results: Experimental results show that: (1) The difference between the estimated driving angle and the true driving angle of the vehicle is within 30°, meeting the accuracy requirements of map-matching algorithms. (2) The overall position correction accuracy of the trajectory is within 30 meters, with potential sub-meter accuracy at best. This performance is primarily influenced by the quality of the road network data, highlighting that the method relies on high-quality road network data to effectively address abnormal trajectory data with significant positional offsets. (3) High-quality trajectory data obtained after pre-correction can significantly enhance the accuracy of map-matching algorithms, resolving issues related to incorrect matches and relative positional deviations. Conclusions: The proposed innovative method effectively detects and corrects abnormal driving angles and overall trajectory offsets, significantly enhancing the quality of crowdsourced trajectory data. This improvement further aids in increasing the accuracy of trajectory position correction in map-matching algorithms. Additionally, it offers valuable technical support and methodological guidance for advancing the application of high-definition map crowdsourcing updates.

     

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