基于单应性矩阵的模型迎角单目视频测量方法

风洞试验中模型迎角的精准测量是降低阻力系数误差的重要途径之一，为此，提出了基于单应性矩阵的模型迎角单目视频测量方法。该方法通过两个单应性矩阵，获取试验过程中相机实时位姿和标记点物方空间位置坐标，应用坐标旋转关系，完成试验模型的迎角测量。数值仿真试验结果表明：迎角测量误差与待测标记点到风洞壁板间的距离偏差近似为线性关系，因此，当标记点不满足共面条件时，可根据该特点进行测量误差修正。静态标定和风洞迎角测量试验结果表明：修正系统误差后，迎角实测数据的测量准度在0.01°以内，精度不超过0.012°。本文方法易于实施，工程实用价值强。

Single camera videogrammetry measurement method of angle of attack based on homography matrix

Accurate measurement of the angle of attack of the model in wind tunnel test is one of the important ways to reduce the error of the drag coefficient. Therefore, this paper proposes a single camera videogrammetry measurement of angle of attack based on homography matrix. Using two homography matrices, the proposed method obtains the real-time pose of the camera and the coordinates of the reference mark points during the wind tunnel test, and applies the coordinate rotation relationship to measure the angle of attack test model. Numerical simulation results show that the deviation of the distance between the measuring mark points and test section wall is approximately linear with the measurement error of angle of attack. Therefore, this measurement error can be corrected relying on this feature when the marker points do not satisfy the coplanar condition. The static calibration and wind tunnel tests show that by correcting the system error, the accuracy of the measured angle of attack does not exceed 0.01°, and the precision is within 0.012°. The method introduced in the paper is easy to implement and the engineering practical value is huge.