Abstract: 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.

Key words: homography matrix, wind tunnel test, angle of attack, single camera, videogrammetry measurement