S变换轮廓术是一种采用无损可逆时频技术来获取物体三维面形的方法。该方法利用S变换的多分辨率特性,从单幅条纹中高精度地提取相位信息,重建物体的三维面形。分析了影响S变换轮廓术精度的因素,提出采用分段均值和曲线拟合的方法来抑制条纹背景分量,在S变换核函数中引入调节因子来进一步提高S变换的时频分辨能力。模拟和实验均验证了所提方法能更准确地得到S变换系数,提高物体三维面形的重建精度。

S-transform profilometry is a three-dimensional shape reconstruction method based on a lossless and reversible time-frequency technology. This method, a multiresolution technique, can reconstruct the three-dimensional shape of the tested object using the phase information demodulated from a single-shot fringe pattern. Herein, we analyze the factors that may affect the accuracy of S-transform profilometry. Piecewise-mean and curve-fitting methods are proposed to eliminate the background intensity of the fringe. In addition, adjusting factors are introduced into the S-transform kernel function to improve the time-frequency resolution. Simulation and experimental results verify that the proposed method exhibits high accuracy of three-dimensional shape reconstruction because of accurate S-transform coefficients.