Study Of The 3-D Body Scan Technology Based On Grating Projection

Recently the 3-D body scan technology has developed fast and become the one of the most important study objects in the intelligentized apparel industry. As it can reconstruct the 3-D body's figure, so it can be combined with the apparel CAD and MTM systems, widely used in manufacture, bodily form research and virtual reality.Originally the 3-D reconstruction technology was used in the reverse engineering, then it was used wildly and a lot of correlative research methods and technologies were came forth. At the present time the 3-D Reconstruction technology which measure a human has not been published yet, and a lot of studies about 3-D reconstruction technology is not suitabe to measure person. It is very important to the universities which have fashion engineering department to master this technology to improve further research,but there is less study about it now. So in this paper,a 3-D body scan system is structured by the approaches and arithmetics which have been chosen, combined and optimized to make the system to be low cost, practical, credible and engineering.This syetem is based on the four-step phase shifting principium, the standard grating which was created by computer is projected onto the specimen, then the deformed grating pattern images which contains information about the surface topography of three-dimensional object can be recorded by the camera which is in the direction that has an angle from the projection axis. This paper expound the system's elements and arithmetics detailedly. It includes a series of procedures:system calibration, image pretreatment, phase demodulation, phase unwrapping, data reconstruction and the 3-D connecting.The system calibration is the base of the experiment. In this paper the problem of the projection lens shift in the system calibration is advanced for the first time and the resolvent can make the fringe keep linearity. The phase unwrapping technoliogy is always the important and difficult part of the 3-D reconstruction technology. This paper advances to use the second difference algorithm and region-growing algorithm to unwrap the wrapping phase which can reduce the effect by noises. In addition, this paper advance to average the threshold value in the algorithm to optimize the effect. This method is proved to be suitable for the 3-D body reconstruction.At the end, this paper discusses detailtly the system's errors because of the apparatus, position, and systemic parameters, and then recommends the inextricable issue and the further research.