一种提高视频车速检测精度的方法

通过对基于虚拟线的机动车视频测速方法的精度分析，提出了一种提高测速精度的方法.该方法在车道上定义一个矩形检测区，该检测区在视频图像上呈现出梯形，采用二维图像标定方法将梯形图像区域中任意一点的图像坐标准确地映射为检测区内对应点的地面坐标.通过在车辆经过检测区的视频图像中选取适当的图像帧，可以获得车辆的位移及对应的时间间隔，从而获得较高精度的速度测量结果.

A Method to Improve the Accuracy of Video based Vehicle Speed Measurement

With an analysis of the insufficient accuracy of the video based vehicle speed measurement based on virtual lines, a method was proposed to improve the measurement accuracy. A rectangle detection area was defined on a road lane, but it was displayed as a trapezoid on the images captured by the video camera. By using two dimensional image calibration transformation, the image coordinates of any point within the trapezoid area could be accurately mapped to the ground coordinates of corresponding point within the rectangle area. By selecting adequate image frames captured during the vehicle running across the detection area, the displacements of the vehicle and corresponding time intervals could be obtained by the proposed algorithm and thus the vehicle speed could be achieved with better accuracy.