| Summary: | 碩士 === 國立成功大學 === 機械工程學系 === 107 === In this thesis, we would apply the spiral phase quadrature transform and optical flow method to the fringe projection method to construct the single-shot fringe projection surface profile measurement system which can measure in real time. The experiment could be fulfill by these step: first, change the CCD of phase-shift method to color camera, and the black and white fringe into the red and green one. Second, get a color fringe image by color camera and extracting out the red and green channel fringe images. And then with spiral quadrature transform and optical flow method we could obtain the fringe pattern with a phase difference of 90 degrees. Last, the surface profile of the specimen could be issued from the unwrapping phase and the algorithm of fringe projection method.
This thesis is divided into two parts-- system analysis and experiment. In the former one, we study the impact of pitch on the system measurement results by analyzing the projecting fringe of different pitch. The result reveals that the smaller the pitch, RMSE reduced by 0.034mm ~ 0.087mm, RMSE percentage reduced by 0.49% ~ 4.18%. Furthermore, bring the setting parameters, the actual pitch of fringe and the limit height of measurement into the theory for calculation will show that the phase difference limit value caused by the rising height is less than 2π. That means when calculated the actual measurement height limit value by phase difference 2π, the result will be an error.
For the experiment part, we measured four groups of different specimens, and compared the measured values with the measured values of SMS-300M and four-step-phase-shifting fringe projection method to verify the accuracy of the system. The results show that the root-mean-square error of the specimens with height 0.5mm ~ 5mm is about 17μm to 55μm, and the mean-absolute error is about 13μm to 28μm. The RMSE percentage of the specimens with height 13mm is about 3.6% to 3.8%, and the MAE percentage is about 2.8% to 3.0%.
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