Patent ID: 7016517

Claim:
A travel road detector, comprising: 1) an image pickup section producing a road image of a forward travel road in front of a driver's vehicle; 2) a setting section setting, on the road image, small areas for lane marker detection; 3) a lane marker detector detecting, in the small areas, lane markers on both sides of a travel lane for the driver's vehicle as lane marker detection points; 4) a first calculator determining that a both-side lane marker detecting state is present when the number of lane marker detection points of the lane marker on each side of the travel lane is greater than or equal to a first predetermined numerical quantity, and at the same time the total number of lane marker detection points of the lane markers on both sides of the travel lane is greater than or equal to a second predetermined numerical quantity, and calculating, from information on the lane marker detection points, a travel road model parameter representing a shape of the forward travel road when the both-side lane marker detecting state is satisfied; 5) a forward vehicle detector detecting a height of a predetermined part of a forward vehicle traveling ahead of the driver's vehicle when the both-side lane marker detecting state is present; and 6) a second calculator determining that a one-side lane marker detecting state is present when the both-side lane marker detecting state is not present, and at the same time the number of lane marker detection points of the lane marker on either one side of the travel lane for the driver's vehicle is greater than or equal to a third predetermined numerical quantity, and calculating the travel road model parameter from information on the lane marker detection points, and information on the height of the predetermined part of the forward vehicle detected with the forward vehicle detector.