基于有效信号提取的白光干涉信号快速处理方法

Fast white light interference signal processing method based on effective signal extraction

针对白光扫描干涉术在垂直大范围扫描过程中的测量效率问题,提出了一种基于有效信号提取的白光信号快速处理方法。使用白光LED光源,建立了双峰频谱分布模型,并使用该模型进行了仿真实验,给出了不同算法在特定采样步长下所需的最小采样区间长度确定方法,在不改变测量精度的条件下减少了解算所需的数据量,并使得轮廓解算可以在采样结束前开始。针对垂直大范围扫描过程中的背景值波动问题,给出了一种基于背景集合的白光干涉信号背景分离方法,并通过与几种常见信号处理方法的比较,证明了背景值提取的完整性,有效消除了背景值波动现象对测量精度造成的影响。最后将上述方法应用于自主设计开发的白光轮廓仪,使用傅里叶变换法精确测量了U盘接口表面形貌特征。测量结果表明:从扫描开始到获得表面高度信息的总时间减少了49.02%。

Focusing on the measurement efficiency of white light interferometry in vertical large-scale scanning process, a fast white light interference signal processing method based on effective signal extraction was proposed. The bimodal spectrum distribution model of the white LED light source was established, and the simulation experiments were carried out by using this model. From the simulation results, the minimum sampling interval length required by different algorithms at a specific sampling step was given, which reduced data volume without changing the measurement accuracy and allowed the calculation to start before the end of sampling. To eliminate the fluctuation of background value in vertical large-scale scanning process, a background value extraction method based on background set was introduced. By comparing with several signal processing methods, it was proved that the extraction method can effectively eliminate the influence on measurement accuracy. Finally, the proposed method was applied to the self-designed white light interferometer and a U disk interface was tested in using Fourier transform method. The results show that the total time from scanning to obtaining surface height information is reduced by 49.02%.