Three-dimensional Profile Measurement Technique Of Fractional Frequency Doubling Projection Grating

The three-dimensional profile of objects with steep changes in morphology was measured by the fractional doubling grating projection fringe three-dimensional profile measurement system.This measurement technique solves the problem that the folded phase cannot be expanded due to the frequency span being too large in the frequency-doubled projection grating,resulting in the inability to reconstruct the object.At the same time,it can also be used to solve the problem of reduced resolution caused by the occurrence of moiréfringes in frequency-doubled projection gratings,which greatly improves the measurement accuracy.This method effectively solves the problem of steep changes in object shape,and provides a practical method for the 3D vision technology of robot gripping operations in recent years.The main research work is as follows:1.Prepared a computer program and produced a series of raster images for continuous projection.Using the image processing technology,a computer program for making a fractional double frequency projection raster image is written,and the program is used to make a four-step phase shifted fractional double frequency raster image.2.To establish a three-dimensional profile measurement system for different types of wires.Fractional frequency doubling projection grating stripes are sequentially projected on the surface of the wire through the portable projector in phase order,and a digital camera is used to collect the fringe image deformed due to the height modulation of the wire.3.Compiled a computer program for the reconstruction of the three-dimensional profile of the wire.The fringe image processed by the Gaussian filter is calculated by a computer,and the wrapped phase of each pixel is obtained based on the four fringe images of different phases,and the phase of the wrapped phase is expanded step by step using the fractional frequency doubling projection grating phase expansion method The unfolding phase of the frequency,the relative height distribution of the wire is obtained to obtain the three-dimensional shape information of the wire.4.The three-dimensional surface measurement technology of the fractional octave projection grating is used to measure different types of wires,and a relatively complete three-dimensional shape of the wire is obtained.The experimental results are compared with the real object,and the details and steepness of the wire can be observed.The edges are completely restored,indicating that the research method is practical and effective.