Modulation Measurement Profilometry Based on One-Dimensional Frequency-Guided S-Transform

Abstract The modulation measurement profilometry employs the principle of vertical measurement, where the projection optical axis and the observation optical axis are aligned. This technique effectively avoids the limitations of shadows and occlusions inherent in optical 3D sensing methods based on the triangulation principle. To further enhance the accuracy of modulation information extraction, a one-dimensional frequency-guided S-transform method (1D-FGST) is introduced, which incorporates the parameter p to control the width of the Gaussian window, offering better time-frequency analysis characteristics compared to the traditional one-dimensional S-transform method (1D-ST). It can extract high-frequency detailed information about object, achieving a root mean square (RMS) error of 4.24 μ m within a depth range of 1100 μ m.