| 摘要 |
PROBLEM TO BE SOLVED: To extract a white line drawn on a road, for example, with a simple constitution and with high reliability, by referring to the gradation value of an attentional pixel and also the gradation value of pixels existing on both sides of the attentional pixel with a space of prescribed width secured respectively and outputting the smaller difference of both gradation value. SOLUTION: The video signals (a) are inputted from a TV camera mounted on an automobile. Two delay units 1 are used in series to refer to the gradation value C of an attentional pixel contained in an inputted gradation image (a) and to refer to the gradation value L and R of two pixels existing at both sides of the attentional pixel with a space of prescribed width (h) secured respectively. A subtracter 2 inputs the gradation value C and R and the gradation value C and L to calculate (C-L) and (C-R) respectively. A selector 3 selects the smaller one of acquired (C-L) and (C-R) and outputs a signal (b). Then a bright part that is smaller than width 2h is outputted as the positive value, and (h) is set in response to the width of a white line. A comparator 5 binarizes the output (b) of the selector 3 based on the threshold generated by a threshold generator 4 and outputs a signal (c). |
