中文摘要：

针对利用图像配准测量物体的旋转角度问题,本文提出利用改进的BRISK特征点求取。该方法利用BRISK初步得到特征点后,给特征点间的汉明距离设置阈值初步筛选,以余下点对的最小汉明距离为阈值进行二次筛选得到最终的匹配点对,最后这些点对分别结合OTSU（最大类间方差）、仿射矩阵及特征点组成的直线斜率的中位值三种方法,计算物体旋转角度及所需时间。实验结果表明,利用二次阈值对BRISK特征点进行筛选,配准度有了很大提升;三种方法测量角度的绝对误差基本都在1°以内,且消耗的时间均不超过1 s,而且对噪声,遮挡,光照变化等有一定的鲁棒性。

英文摘要：

In order to get the rotation angle accurately and quickly by using the image registration, the Binary Robust Invariant Scalable Keypoints（BRISK） are improved. Firstly, we can get the origin key-points by BRISK, and set a threshold to the Hamming distance between the key-points to pick out the matching pairs. Afterwards, further screen the matching pairs by the minimum Hamming distance between them. Finally, combining the matching points respectively with OTSU, the affine matrix and feature points of the slope of the straight line the median value, the rotation angle and the time it costs are measured. Experiments show that the secondary hamming distance to get the matching pairs can improve the accuracy of the matching point, the error of rotation angle measured by these three methods is not more than 1 degree, and the time they cost is less than 1 second. Besides, it keeps certain robustness to noise, loss of outline, illumination variation and so on.