Tham khảo tài liệu 'dynamic vision for perception and control of motion - ernst d. dickmanns part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Multiple Edge Measurements for Road Recognition 225 Figure shows such a case. Only feature extraction has to be adjusted Since the road boundaries are not crisp large masks with several zeros at the center in the feature extractor CRONOS are advantageous in the near range the mask shown in Figure nd n0 nd 7 3 7 yielded good performance see also Figure center top . With the method UBM it is advisable to work on higher pyramid levels or with larger sizes for mask elements values m and n . To avoid large dis- Figure . Recognition of the skeleton line of a dirt road by edges in near range with large masks and by the center of brighter regions in ranges further away for improved robustness. Road width is determined only in the near range. turbances in the far range no edges but only the approximate centers of image regions signifying road by their brightness are determined there in Figure other characteristics may be searched for otherwise . Search stripes may be selected orthogonal to the expected road direction windows 7 to 10 . The B and zB coordinates of the road center point in the stripe determine the curvature offset and the range of the center on the skeleton line. Experimental Results In this section early results 1986 in robust road recognition with multiple redundant feature extraction in eight windows are shown. In these windows displayed in Figure one microprocessor Intel 8086 each extracted several edge candidates for the lane boundaries see figure . On the left-hand side of the lane the tar filling in the gaps between the plates of concrete that form the road surface gave a crisp edge however disturbances from cracks and dirt on the road were encountered. On the right-hand side the road boundary changed from elevated curbstones to a flat transition on grass expanding onto the road. Features accepted for representing the road boundary had to satisfy continuity conditions in curvature heading change over arc length .
