Appl. Sci. 2023 , 13 , 1389
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The results of filtering the sample image are shown in Figure 5a. Figure 5b shows the image of the sample itself with the detected edges of the sample: left (green) and right (red). Detecting the left edge is very difficult due to the low contrast in the image, hence in further analysis it was decided to rely on the detection of the right edge. This cannot be generalized to all cases. The contrast depends on the direction and lighting of the sample. In the future, choosing the right filter mask should be an option for the analysis algorithm.
( a ) ( b ) Figure5. ( a ) The result of filtering the image of the paper sample during the measurement, ( b ) the image of the sample with the detected left edge marked in green and the right edge in red. Figure 6 shows the result of filtering the checkerboard images placed on both handles of the testing machine and the places where the corners marked with red dots were detected. To detect the corners between the white and black fields, regardless of their order, filtering was repeated twice with the filter mask rotated 90 degrees. Next, in the obtained images, the places of the corners were detected independently by detecting the maxima in the images after the filtering and the resulting information from both images was combined.
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( e ) ( f ) Figure 6. The result of filtering the checkerboard image on the moving ( a , b ) and still ( d , e ) handle and images of the handles themselves ( c , f ) with the corner detection points marked in red. Pictures ( b , e ) show the result of filtering with a filter with a mask rotated by 90 ◦ .
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