Development of a System Measuring Vehicle Motions on Video Images

本研究发展一套以视讯影像量测车辆运动之系统，以追踪车辆轨迹。视频图像是由放置在观测气球上的摄像机拍摄的，覆盖了约200米的高速公路路段。在建立了手动测量系统的基础上，开发了自动测量系统，并对系统进行了性能检验，该系统除了能对交通检测器所观测到的交通量、密度、速度等常规观测指标进行测量外，还能对微型车辆的运动进行观测。1.图像变换将视频图像变换到与标准图像相同的坐标上，2.车辆识别利用变换后的图像，通过与背景亮度的比较来识别车辆，系统通过比较手动系统和自动系统的性能来检查性能。结果表明，自动系统的车辆识别率与人工系统的车辆识别率基本相当，但自动系统的识别精度与人工系统的识别精度存在一定的差异，主要是由于识别出的车辆和航迹反射较弱。

This study develops the system of measuring vehicle motion on video images for the purpose of tracking vehicle trajectory. The video images are taken by the video camera being placed on an observation balloon, and covers about 200 meters' expressway section. After we established manual system of measuring, we developed automatic system of measuring and checked the system performance.In addition to usual observation index observed by traffic detectors such as traffic volume, density and velocity, this system enables to observe micro vehicle motions.The process of this system are consist of two parts as follows ;1.Image TransformationVideo Images are transformed to same coordinates as the standard image, by adjusting predetermined standard points.2.Vehicle RecognitionUsing transformed image each vehicles are recognized by comparing brightness with one of background.The system performance are checked by way of comparing performance of manual system with one of automatic system. In result, rate of vehicle recognition of automatic system is almost equal to one of manual system, however, accuracy of automatic system has some difference mainly caused by recognizing feeble reflective vehicle and tracks to one of manual system.