| Three-dimension (3-D) measurement is a kind of measurement method that is used to abtain profile of 3-D objects in the size and shape. Compared with the traditional two dimension measurement, 3-D measurement can record more information of an object, and can rebuild the object shape more actually and completely. In recent years, the science and technology have won continually developed, the computer science is growing rapidly, and the technology of signal auto-process is going to be mature, especially the visual programming tool and the high resolution digital camera is present.The author discusses the history of 3-D measurement, and summarizes a few of methods of 3-D measurement. Then FTP withπphase shift is choosen as the demodulation method of 3-D profile measurement system in this thesis. The author makes some experiments in simulation and real to analyze the measurement effect of fringe pattern and color grating. It turns out that the color grating is more precise than black/white in the measurement. Based on this method, the author implements an integrated measurement system which consists of projection, image acquisition, demodulation and result display, and the result of experiment meets the requirement of design. This system uses digital camera with USB2.0 port as the hardware of image acquisition with the advance in reliability and rapidity. The software platform of this system's measurement part is LabVIEW. Meanwhile, the author chooses Matlab to finish the data processing part. Because of various factors, the images captured are different from simulated one, so the image should be processed before demodulation operation to decrease errors. The reconstruction result with smoothing and amending is better than that of without processing. Finally, the measuring error sources in this measurement processing are analyzed in this paper.This paper mainly has the following innovations:1. The measurement system is setup by digital camera with USB2.0 port to implement the image acquisition system. It is convenient to connect camera with PC and the capture card is not needed. Besides, this camera has high resolution ratio, high precision, high definition, good color rendition and low noise, and can be applied to commerical product.2. Use LabVIEW and Matlab as the software development platforms to implement and the program is finished in mix. The advantages of the platforms are used and the integrated 3-D profile measurement system is constructed that consists of projection, image acquisition, demodulation and result display.3. The mean filter digital and intensity balance method is used to image to decrease the measurement errors and rise the precision of measurement.4. The color grating withπ/3 phase coding structed light is used to implement the 3-D profile measurement. The modulation precision is higher than black and white fringe pattern. |
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