微结构低重叠度大范围三维拼接方法

A low overlap rate and large scope 3-D stitching method for microstructures

针对微结构大范围无损测试问题,提出了一种低重叠度的三维结构拼接方法。首先基于实验参数将结构特征提取区域限制在测量过程中的重叠区域,以减少误匹配出现的可能性并提高计算效率;在上述区域内,通过SIFT(scale-invariant feature transform)算法进行特征点提取;在特征点匹配阶段,根据测量系统参数进一步提出缩小匹配点对搜索范围的方法以提高特征点匹配可靠性;最后以重叠区域的局部连续性为依据,计算校正矩阵以校正测量过程中环境扰动带来的拼接结构错动。实验中,将本方法与目前商业设备的拼接测量功能进行了对比。实验表明,本文方法不但适用于特征丰富的结构,也适用于相似度高的阵列性结构,可在重叠度为6%时实现有效拼接。

In order to achieve the large scope evaluation for micro-structures, a low overlap rate and large scope 3-D structure stitching method is presented in this paper. According to the features of micro-struc- tures, the area for the feature points extraction is designated in the overlap region in the first step based on the experimental configuration, in order to reduce the possibility of incorrect matching and increase the processing efficiency. Inside this special sector, the feature points are extracted through SIFT algo- rithm. During the feature points matching process, the matched points searching area is optimized based on the testing profiler parameters in order to increase the matching reliability. According to the local con- tinuity inside the overlap region, the mismatch between the stitched structures due to the environmental disturbance during the test is corrected by a correction matrix in the last step. The comparison experi- ments between the proposed method and a commercial profiler are carried out,which show that the new algorithm is not only effective for the structure with rich features,but also applicable for the array struc- tures with unobvious features. The further experiment shows that the stitching could be successfully a- chieved at overlap rate of 6%.