Coordinate Extraction of Measuring Points for Sensing Optical Fibers on Wafer Surface

In order to solve the problem of difficulty in extracting the coordinates of actual measuring points in the detection of precision components by distributed sensing optical fiber, a method of extracting the coordinates of optical fiber measuring points based on machine vision is proposed. Firstly, a strip light source should be applied to side lighting to avoid the specular reflection of the wafer. Take pictures from four directions of 0°, 45°, 90°, and 135°, and then superimpose them into a completely original image. And this image is preprocessed by image contrast enhancement and bilateral filtering. Secondly, the Canny algorithm is adopted for sub-pixel edge recognition of optical fiber images. The optical fiber is extracted segment by segment by using the Gaussian line detection method and obtaining the full optical fiber path. Finally, the coordinates of the measuring points along the sensing optical fibers can be determined under different spatial resolutions of the distributed optical fiber system.