| The 3D-profile measurement has a number of applied values which make them attractive for use in auto-machining, quality detecting, CAD, profile modeling, biomedicine, machine vision and sculpture field etc. Recently, as one method of 3D-profile measurement, the method of projection Grating is exceedingly studied by researchers for its advanced properties of face-field measurement, real-time recovering and broad measure-scope. However , as the 3D data recovering process is serial and the following data is depended on the data achieved before ,the error located in one point will transfer and finally make the whole recovering data wrong. This prevents this method being used abroad yet. And also , how to get the 3D data with simple measuring equipments is must considered in order to make this method useful.In this dissertation, the aim is focused on completing a 3D-profile measurement system using grating projection phase method and designing a measuring unit connected a personal computer to recover the thee-dimension profile. However, the dominating work of this dissertation is contributed to some hotpots and difficulties rooting in this method. In view of these, following works are listed and executed.1. The sources of the propagation error in the unwrapping process was analyzed. According to the experiment data and the stepped displaying of unwrapping process, the path and origin of the propagation error was traced and found to be lack of sampling , respectively. It is considered that the propagation of error induces a disconnected phase distribution and that, the final wrong recovering three- dimension data results. In order to resolve this problem, a new unwrapping method based on the dual-frequency grating method was proposed. The final measuring result shows that the resolving power of the measuring system is not reduced and the propagation error is avoided commendably with this novel method proposed in this paper-and it works well.2. A new system calibration method was proposed for predigesting measuring equipments and operating procedures to acquire accurate measuring result, which needs less position-correlation between cameras and projecting mechanism instead of exacting position coupling conditions (parallel or vertical to the optical axis) of traditional technique. It is sounded to be easier to recover the 3D-profile with the novel calibration method, in which system parameters are calculated by PC program as well as the camera and measuring of the referenced object whose size is pre-supplied was calibrated with this method. The recovered measuring results sufficiently suggest that more accurate recovered data can be gotten with this novel calibration system than that of the traditional calibration method, and it certainly has a good applying foreground in the future.3. Two cameras were used to gather object' s image, as a result, the measuring shadow is greatly reduced and the covered scope is widely extended. There are two factors infecting the transverse and longitudinal resolving power, one is the related position between camera and measured object , and the other is the facing direction of the measured object' s surface. The method of modifying the transverse and longitudinal resolving power is given subsequently. Using the modified result which the resolving power in the transverse orientation is accordant and the longitudinal orientation also, the experiment of the fusion of data was performed. The original merging method which is just about simple data adding is improved by adopting the liner merging method and the merging result is fine.4. A measuring software was programmed in C++ with the function of the real-time grate projecting, image gathering, system-parameter calculating, 3-D data showing and so on. Many measurements have validated that the software will be a practical tool in 3D-profile measurement for its lower requirement to computer hardware and its operability.
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