| 摘要 |
PROBLEM TO BE SOLVED: To stably extract a white line lane mark by excluding the influence of blooming and a smear which are generated by means of a bright light source. SOLUTION: An analog image signal obtained by a CCD camera is fetched by an edge detecting circuit arid the edge detecting circuit 10 detects a white line edge based on the change of brightness in an image signal. That is, when the absolute value ΔDi of difference between data Di and Di-1 is larger than a prescribed threshold value A, the probability of the white line edge exists with the output of a comparator 15 as 'one'. The comparators 16 and 17 compare data Di-1 and Di with the threshold value B which is set in the neighborhood of the saturated level of brightness in CCD in parallel with the comparison operation of the comparator 15. In this case, the output of the comparators 16 and 17 becomes 'zero' at the time of Di-1>=B or Di>=B and edge data at that time is made to be inavlid (EDi=0). |
