基于SVMD-HD去噪的白光干涉解调算法

White-light interference demodulation algorithm based on SVMD-HD denoising

垂直扫描白光干涉法(VSWLI)是一种非接触式三维表面轮廓测量方法。蝙蝠翼作为VSWLI当中一种固有的缺陷,尤其在被测样品的台阶高度小于光源的相干长度时,台阶边缘处的蝙蝠翼尤为显著。相移干涉法不存在这种缺陷,但是存在相位模糊的问题。提出一种将Carré等步长相移算法与快速傅里叶变换(FFT)相干峰值检测技术相结合的白光干涉解调算法。该算法基于逐次变分模态分解(SVMD)与Hausdorff距离(HD)联合去噪。分别以高度为500 nm和1200 nm的连续台阶器件和高度为10μm的标准台阶作为测试样品,进行实验测量验证。所提出的算法能够有效地抑制台阶高度跳变处的蝙蝠翼,克服相位模糊问题。

Vertical-scanning white light interferometry(VSWLI)is a non-contact three-dimensional surface profile measurement method.As an inherent defect in VSWLI,the batwings are especially significant at the step edge when the step height of the measured sample is smaller than the coherent length of the light source.The phase-shifting interferometry does not suffer from it,but has phase ambiguity problems.A white-light interference demodulation algorithm that combined Carréequal-step phase-shifting algorithm with fast Fourier transform(FFT)coherence-peak-sensing technique was proposed to overcome the above problems.This algorithm was based on successive variational mode decomposition(SVMD)combined with Hausdorff distance(HD)denoising.The continuous step devices at 500 nm and 1200 nm height and the standard steps at 10μm height were used as test samples for verification of experimental measurements.The proposed algorithm can effectively suppress the batwings effect at the step edges and remove the phase-ambiguity problems.