| With the development of computer technology, new CCD devices and high level imageprocessing method, the application of three-dimension (3-D) shape measurement and3-Dreconstruction are more and more important, especially in reverse engineering, humanphysical examination, medical instruments, CAD/CAM and industrial control, etc. It is a greatsignificance to acquire3-D object measurement date rapidly, efficiently and high precisely,which is also a hot research topic. Though the traditional contact measurement owns its ownadvantages, its mechanical measurement structure is very complex with low measuringefficiency, the worst, it often causes some damages to the surface of object. Gradually, thenon-contact measurement methods arise as important ways to fulfill3-D measurement. Thegrating projection is one of them. Although grating projection has no unified and convenientmeasurement system, and the problem of high accuracy measurement and traceability haveproblem have not been solved well yet, it has a good development prospect.By using the latest object mapping relation system and3-D measurement method oflattice calibration,3-D measurement and reconstruction to a standard object has been realized.Based on digital grating phase-shifting, the geometric constraints of digital-grating and CCDhas been decreased，and phase shift error, brought by non-standard sine grating stripe, hasbeen avoided. The whole measurement system is more feasible and precision, which isconsists of LCD, CCD, precision platform and checkerboard calibration board, etc.In summary, the principle of digital grating phase-shifting and algorithm of phaseunwrapping has been analyzed in this paper. System structure of digital grating phase-shiftingand system calibration methods are studied. The principle and process of the board calibrationmethod is mentioned too.in the end the3-D information measurement and reconstruction to atrapezoid-section object is realized as experiment result. |
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