Super-rapid three-dimensional topography measurement method and system based on improved fourier transform contour technique

A super-rapid three-dimensional topography measurement system based on an improved Fourier transform contour technique, the system comprising:

• a measuring subsystem, the measuring system comprising a projector, a camera and a computer;
• a Fourier transform contour technique subsystem;
• and
• the computer being programmed to function as a calibration unit, a projection and acquisition image unit, and a three-dimensional reconstruction unit,
• wherein:
• the Fourier transform contour technique subsystem consists of a background normalized Fourier transform contour technique module, a temporal phase unwrapping technique with a projection distance minimization (PDM) module and a reliability guided compensation (RGC) of fringe order error module,
• the calibration unit is configured to calibrate the measurement subsystem so as to obtain calibration parameters,
• in the projection and acquisition image unit, the projector projects n patterns and m (m=n) all-white images cyclically to a measured scene, n≥2, wherein then patterns are binary high-frequency sinusoidal fringes with different wavelengths, and the m all-white images are with pixel value of 1, and projected between every two binary high-frequency sinusoidal fringes, and the n+m images are collected synchronously by the camera,
• the background normalized Fourier transform contour technique module is configured to process the collected n+m images so as to get wrapped phases, the temporal phase unwrapping with the PDM module is configured to obtain a preliminary absolute phase, and the RGC of fringe order error module is configured to correct an initial absolute phase, and
• the three-dimensional reconstruction unit is configured to reconstruct a three-dimensional topography of the measured scene with a corrected absolute phase and the calibration parameters to obtain three-dimensional spacial coordinates of the measured scene in a world coordinate system, thereby accomplishing three-dimensional topography measurement of an object.