Design Of 3-D Shape Measurement System Based On Fast Scan-phase-shifting Algorithm

Optical 3D profilometry access to a wide range of applications for the characteristics of automation and a non-contact,high precision,easy to achieve.In order to meet the requirements of actual measurement,many optical 3D profilometry system and instruments are developed,which can meet certain measurement requirements.However,because of the complex structure,high cost,low precision and poor real-time ability,the large-scale applications are severely constrained.Therefore,designing and developing a complete performance of the three-dimensional topography tester have important research significance and application value.This paper is based on the phase shift method for measurement.At the same time combined with the advantages of light cutting method,use one-dimensional scanning method to achieve panoramic measurement.First,fixed projector and camera,place the tested object on the electric platform,realize the scanning measurement of the object by controlling the movement of the electric platform;Then the central part of the scanned image is processed by the scanning phase shift algorithm.Finally,obtain the whole shape of the object by phase stitching,system calibration and coordinate transformation.A set of 3D profilometry instrument based on fast scanning phase shifting algorithm is designed.The main contents are as follows:1.The 3-D topography measurement method is introduced systematically.Several common methods of optical 3-D surface measurement methods are introduced and analyzed.Compared with each other,we propose a scanning phase-shift algorithm in this paper.2.The Stoilov algorithm is studied and analyzed,then the experiments are carried out to find an algorithm suitable for the measurement system.The influence of the phase shift step length on the measurement results is studied.The results show that the measurement result is the best when the phase shift step length is ?/2.3.The basic measurement principle and method of 3 topography measuring instrument are introduced in detail.The phase extraction and phase splicing method of scanning measurement are studied.Herein,we find a suitable phase extraction and image splicing method for this measurement system.4.The calibration method of the scanning measurement system is studied and the mapping relation between the height and the phase difference is found.And the experiments verify the correctness of the corresponding calibration methods.5.A complete set of scanning measurement system is designed based on the measurement principle and method.The image acquisition system is designed by C++Builder software,which realizes the automatic acquisition and preservation of scanned images.The image processing program is written by Matlab software to complete the phase extraction,phase unwinding,image splicing,system calibration and 3D display of the scanned image.The system implement automated measurements.The measurement experiment of different objects is carried out by using the system.The good measurement results are obtained and the feasibility of the measurement system is verified.