When the topography of microstructure is reconstructed by white light interference, the scanning range of the interference fringe is used to be fixed. due to the uncertainty of the angle between the object surface and the reference surface, the actual scanning range varies accordingly. In order to obtain an accurate interference scanning range, this paper proposes an improved ViBE algorithm to automatically configure the scanning range by identifying interference fringes. To solve the ghost that occurs in the traditional ViBE algorithm when detecting interference fringes, the pixel foreground life dictionary is established to record the life cycle of the foreground pixels. The static foreground points are screened out, and the background model of the static foreground points is re-initialized to achieve initial suppression of ghosts. The foreground pixel connected region is analyzed to achieve elimination of residual ghost noise. Finally, the number of foreground pixels is taken as the basis for the existence of interference fringes. The experimental results show that the improved ViBE algorithm can quickly eliminate the ghost noise in three images and obtain the accurate interference fringe binarization foreground image.
Periodic systematic error caused by erroneous reference phase adjustments and instabilities of interferometer has a great influence on precision of measurement micro-profile using white light phase-stepping interferometry. This paper presents a five-frame algorithm that is insensitive to periodic systematic error. This algorithm attempts to eliminate the periodic systematic error when calculating the phase. Both theoretical and experimental results show that the proposed algorithm has good immunity to periodic systematic error and is able to accurately recover the 3D profile of a sample.
The non-linearity of the phase shifting mechanism in white light interferometry system can seriously affect the measuring accuracy of the system. In this paper, the correcting method is to combine the displacement feedback control technology with the fuzzy PID control technology. Displacement feedback control mechanism and fuzzy PID controller are designed and then try to figure it out through Matlab simulation and experiment.. The result shows that combining the displacement feedback control technology with the fuzzy PID control technology can fulfill decent overall non-linear correction in the white light interferometry measuring system. Meanwhile, the accuracy of the correction is high and the non-linearity drop from 2% to 0.1%.
Optic fiber coils are the hearts of fiber optic gyroscopes (FOGs). To detect the irresistible errors during the process of
winding of optical fibers, such as gaps, climbs and partial rises between fibers, when fiber optic winding machines are
operated, and to enable fully automated winding, we researched and designed this vision-based error detection system
for optic fiber winding, on the basis of digital image collection and process[1]. When a Fiber-optic winding machine is
operated, background light is used as illumination system to strength the contrast of images between fibers and
background. Then microscope and CCD as imaging system and image collecting system are used to receive the analog
images of fibers. After that analog images are shifted into digital imagines, which can be processed and analyzed by
computers. Canny edge detection and a contour-tracing algorithm are used as the main image processing method. The
distances between the fiber peaks were then measured and compared with the desired values. If these values fall outside
of a predetermined tolerance zone, an error is detected and classified either as a gap, climb or rise. we used OpenCV and
MATLAB database as basic function library and used VC++6.0 as the platform to show the results. The test results
showed that the system was useful, and the edge detection and contour-tracing algorithm were effective, because of the
high rate of accuracy. At the same time, the results of error detection are correct.
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