Action Based On The Three-dimensional Surface Of The Stripe Phase Demodulation Shaped Static Measurement Technology

Optical interferometry testing of measuring 3-D surface topography has a wide application in the feature. It has become important measure means for its high accuracy and no contact. Phase-modulation is used to obtain the measured phase information. Measuring speed and accuracy is improved compared with the conventional interferometry.Phase-modulation contain temporal phase modulation and spatial phase modulation. Phase-shifting interferometry (PSI) requires at least three interferograms to get the phase distribution. This is difficult to implement in the dynamic environment. Spatial phase modulation compared with PSI, requires only one frame of the interferogram, which makes real-time data acquiring and processing of dynamic process possible.This paper presents a testing technology for optical fiber connector end surface based on microscopic interferometry. The interferometer consists of a Mirau interference objective and a tube lens. A CCD camera captures the interferograms to get the phase distribution. The Carre algorithm is used, so the determinate step size of phase-stepping method is unnecessary. This method can obtain geometrical parameters of the optical fiber connector end surface such as surface topography, radius of curvature and apex displacement. The result shows that the lateral resolution is 0.9μm and the vertical repeatability is 9.5 nm of the measurement system.In addition, a 3-D dynamic testing system based on Hilbert transform is introduced. Michelson interferometer is used in the system combining CMOS high speed image sampling system with Hilbert transform. Time series interferograms are captured by a high-speed CMOS camera. The phase information of testing surface is evaluated by Hilbert transform only from one spatial carrier interferogram. Time series is obtained form Hilbert transform and discrete high-pass filtering. 3-D phase unwrapping is used to reconstruct vibration of surface point and recover transient surface topography of the testing surface.