视觉里程计中的相机姿态和高度实时测量方法

在视觉里程计的应用中,实时准确的获得相机姿态和高度数据有助于提高视觉定位的精度.而现有解决方案要么成本过高,要么精度无法满足要求,为此提出了基于路面激光扫描的相机外参数实时测量方法.该方法将两台二维激光扫描仪相互正交安装且向下扫描,对获得的沿着两个方向的路面扫描线使用RANSAC算法估计出直线方程,根据两直线方程求得道路平面方程,并以该平面为参考获得相机相对路面的姿态和高度数据.室内实验结果表明:静态条件下对姿态的测量误差最大约0.1°,高度测量误差最大6 mm;室外动态实验结果表明:与传统的惯性测量方法不同,相机外参数测量结果不受车辆加减速运动的影响,且其动态姿态测量精度明显高于精度为1°的惯性测量系统.由于该方法获得的姿态和高度数据是以道路平面为参考基准,尤其适用于单目视觉里程计中以辅助提高定位精度.

Real-time Measurement of Camera Attitude and Height in Visual Odometer

In the application of visual odometer,acquiring the high-precision attitude and height of camera in real time helps to improve the visual positioning accuracy. But existing solutions are either expensive or low in preci-sion,so we bring forward an real-time method to measure the camera's external parameters based on the laser scan-ning of road surface. Two 2D laser scanner orthogonal installed and downward scan,then the linear equation was es-timated using the RANSAC algorithm. After that,road plane equation is obtained,which is the reference of the cam-era's attitude and altitude data. the indoor experiment results showed that:in the static conditions,the measure-ment error of the attitude is about 0.1 degree,maximum height measurement error is about 6 mm;the outdoor dy-namic experimental results showed that:different from the traditional method of inertial measurement,camera exter-nal parameters measurement results are not affected by the vehicle deceleration influence,and the attitude measure-ment precision is significantly higher than the inertial measurement system which has accuracy of 1 degree. Owing to obtaining the attitude and altitude data as the road plane for reference,the method is especially suitable for assist monocular visual odometry to improving the positioning accuracy.