摘要：针对SIFT算法在圆心检测应用中的特点，分析了SIFT算法中存在的冗余步骤，提出对其进行简化改进：

估计圆心所在的金字塔层，删减金字塔中多余的层数建立，并且通过提高滤除低对比度特征点阈值的办法减少

背景特征点的生成，去掉了特征点辅方向分配和建立辅方向特征点这一步骤。分别对计算机模拟生成的标准

圆和实际的PCB定位标志图像做了圆心检测实验，实验表明，SIFT算法改进后在没有降低其定位精度及对图

像的模糊、光照、仿射等变换适应性的情况下，大大缩短了检测时间，提高了检测效率。

关键词：圆心定位；尺度不变特征变换(sI )算法；特征匹配；冗余-Abstract：In allusion to the characteristics of the SIFT algorithm in the application of circle center 1ocation，redundant proce—

dure is analyzed and a novel predigested and improved method is proposed．By estimating which pyramid octave the circle

center is in，eliminating the redundancy pyramid octaves，and reducing the keypoints generated from the background by in

creasing the threshold for filtering out the keypoints with low contrast，the steps of assigning assistant orientations of the

keypoints and generating keypoints with assistant orientation has been leaved out．Circle center detection experiments have

been carried out for both standard drcles generated by the computer and the real PCB location mark images．The experiment

results show that，wi thout any penalty of the location accuracy，or robustness to blur，illumination，affine transformation，the

detection efficiency has been improved dramatically with the proposed improved method ．

Key words：circle center location；scale inva