THE USE OF MORPHOLOGICAL SKELETONS FOR DIGITIZING SIGNALS, PRESENTED IN BINARY BITMAP IMAGES
The work shows the importance of digitizing graphs using their bitmap images and its application in experimental data processing. The purpose of the research work is the development of the antijamming graphic data digitizing method. Graph images, obtained by the image scanner, are considered. These images can be represented in vector space RGB or they are defined by pixel brightness values. The known segmentation methods of color and gray-scale images are considered. The main problems with digitizing graphs according to their segmented images and their solutions are shown. The advantages of using morphological skeletons of graph images for their digitizing are demonstrated. Results. According to the graphs digitizing algorithm, suggested in the article, at the initial stage the segmentation of scanned images is implemented. The result of segmentation is a binary image with selected graphs and grid lines. The segmented image generally contains holes. The holes in the binary image are small areas that consist of background pixels and they are located inside the image objects. The holes on the segmented images of graphics make it difficult to build their skeletons, similar in shape to the image. To remove holes, the algorithm for holes filling based on the evaluation of the parameters of their contours is offered. After holes filling, the image skeleton is constructed. If graphs images contain grid lines, they are removed after the skeletonization, using the Hough transform to search for straight lines. To obtain digital samples of analog graphs, their skeletons contour tracking according to the algorithm, suggested by Rozenfeld, is carried out. Possible gaps in signals, arising from grid lines removal, are filled in using linear interpolation. Practical significance. The use of the contour analysis considerably increases the interference resistance of the proposed method due to the removal of low-sized objects of an image, which is a hindrance.