基于检测框下边沿的单目视觉车辆测距研究

Study on Monocular Vision Vehicle Ranging Based on Lower Edge of Detection Frame

对车辆测距是当今驾驶领域的热门研究方向。针对传统测距方法测距精度受到车型大小影响的问题以及前车存在的X轴偏移问题,提出了基于检测框下边沿中心点的车辆测距模型。该模型通过使用单目视觉摄像头及车辆检测算法获取前方车辆的位置信息,并通过车辆检测框得出的下边沿中心点坐标,以及相机安装的俯仰角信息综合建立了车辆测距模型,解决了车型大小带来的误差问题;通过构建三角函数模型,解决了前车相对于实验车辆存在的X轴分量问题,并优化改进了前车安全距离的判定方式;设定车尾矩形框中心点横坐标与车辆外接矩形框宽度的比值λ,根据λ取值分情况讨论,使该模型更符合场景应用需要。并提出了基于测距关键点的逆透视变换模型,减小了测距误差。实验表明,改进后测距模型的测距精度不受车型大小的影响且能考虑到前车位置的X轴分量问题,改进后的测距模型相对于传统测距模型,测距误差降低了约1.5%,且测距精度明显提高。

The study on vehicle ranging is a hot research direction in the field of driving today,and aiming at the problems that the ranging accuracy of traditional ranging methods is affected by the size of the model and the X-axis offsetof the vehicle in front,a vehicle ranging model based on the center point of the lower edge of the detection frame is proposed.The model uses a monocular vision camera and vehicle detection algorithm to obtain the position information of the vehicle in front,and establishes a vehicle ranging model by comprehensively establishing the vehicle ranging model through the coordinates of the center point of the lower edge obtained by the vehicle detection frame and the pitch angle information installed by the camera,which solves the error problem caused by the size of the model,and solves the problem of X-axis component of the preceding vehicle relative to the experimental vehicle by constructing the trigonometric model,and optimizes and improves the determination method of the safety distance of the preceding vehicle.At the same time,the ratioλof the abscissa of the center point of the rear rectangular frame to the width of the external rectangular frame of the vehicle is set,and the situation is discussed according to theλvalue,so that the model is more in line with the needs of scene applications.An inverse perspective transformation model based on the key points of ranging is proposed to reduce the ranging error.Experiments show that the ranging accuracy of the improved ranging model is not affected by the size of the model and can take into account the X-axis component of the front vehicle position,and the ranging error of the improved ranging model is reduced by about 1.5%compared with the traditional ranging model,and the ranging accuracy of the improved ranging method is significantly improved.