Profile measurement system based on optical method is becoming widely applied. Among many methods that has been developed, Digital Fringe Projection Profilometry (DFPP) technique provides high resolution results. In processing the 2D image to 3D image, DFPP goes through some steps, which are phase extraction, phase unwrapping, and baseline offset removal. The most important step is phase extraction because this part will extract the deformed fringe information that can determine the accuracy of the 3D reconstruction results. In this paper, there are two methods of phase extraction that is observed, which are phase shifting interferometry and spatial carrier interferometry. Experiments are done with a specific made object that has 3 depths and 2 types of indentations. The results of each phase extraction methods are compared on not only how they reconstruct the flat part and the indentation type, but also how they restore the depth information.
Load and age of rails can result in problems such as breakage, depletion, and expansion that can lead to accidents. Rail inspection has been done manually by operator tracing the rails by walking or riding a special inspection vehicle. These methods obviously are inefficient and inaccurate, as operators might be missing some of the defects. In this research depletion detection of rails are conducted by analyzing changes of the area as well as position shifting of laser spot on captured images by utilizing the triangulation principle. Accuracy and efficiency improvement of rail inspection are expected from this method. Prior calibration of the system was conducted using gauge blocks with thickness varying from 19 to 1 mm with 1 mm decrement. Area changes and position shifting of laser spot are later analyzed through image processing. The system was also implemented on R-54 rail type based on the calibration and later be compared to the manual measurement data. It was shown that the system can detect depletion in rail type R-54. The calibration result shows that the deviation percentage of the measurement of laser area are ranging from 11.41% to 13.48% while for the measurement of laser spot position shift is from 6.91% to 8.80%. Implementation on rail type R-54 shows the deviation percentages between proposed method and manual measurement are ranging from 1.52% to 10.04% for the area measurement, while for the position shifting ranged from 1.11% to 12.68%.
Conference Committee Involvement (1)
Third International Seminar on Photonics, Optics, and Its Applications (ISPhOA 2018)