Patent Document ID: 8548200
Application ID: 12931766
Patent Status: 1

Claim One:
1. A lane-marker recognition system installed in a vehicle, comprising: an image pickup unit that picks up an image of a target region including a road ahead of the vehicle; a light-intensity detecting unit that detects a change in a light intensity of the target region in the picked-up image; a lane-marker recognizing unit that compares the change in the light intensity of the target region in the picked-up image with a predetermined threshold value, and recognizes a region of at least one lane marker in the target region based on a result of the comparison, the at least one lane marker being formed on the road; and a re-determining unit that re-determines the threshold value based on a light intensity of the recognized region of the at least one lane marker; wherein the target region includes the road ahead of the vehicle and a part of air above the vehicle, the lane-marker recognition system further comprising: an intensity ratio calculating unit that calculates a ratio of a light intensity of a first area in the picked-up image to a light intensity of a second area in the picked-up image, the first area corresponding to the part of air, the second area corresponding to a part of the road ahead of the vehicle; and a first threshold correcting unit that compares the calculated ratio with a preset first value, and corrects the threshold value re-determined by the re-determining unit by reducing the threshold value if the calculated ratio is equal to or higher than the preset first value.