| 摘要 |
PROBLEM TO BE SOLVED: To sense a vehicle in a shadow even if it is in the shadow of a vehicle traveling the other lane by setting a measuring line crossing the lane and detecting the luminance level on the measuring line. SOLUTION: A measuring line 27 crossing lanes L1 and L2 is set. The luminance level on a measuring point (i) on the measuring line 27 is detected. A vehicle positioned in a shadow 31 that a vehicle 29 creates is sensed together with the vehicle 29 from data on the obtained luminance level. A shadow density gradient value AKPI(i) at the measuring point (i) is obtained on a shadow part and a shadow inclination normalization luminance level AKP(i) is obtained by normalizing the shadow normalization luminance level AK(i) by the shadow density gradient value AKPI(i). When the vehicle exists in the shadow part, the luminance pattern of the vehicle is overlapped in the pattern of the shadow inclination normalization luminance level AKP(i). Thus, an inclination normalization correlation valueαexceeds a detection threshold and the vehicle in the shadow can be detected.
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