Road parameter calculator

A road parameter calculator comprising:

• an image acquiring unit which is configured to acquire an image of a forward view of a vehicle;
• an edge-point extracting unit which is configured to extract edge points from the image derived by the image acquiring unit;
• a road parameter calculating unit which is configured to calculate a road parameter through a Kalman filter using the edge points derived by the edge-point extracting unit, the road parameter representing a configuration of a road in front of the vehicle;
• a gradient detecting unit which is configured to detect a change in gradient of the road in front of the vehicle;
• and
• an edge-point limiting unit which is configured to define a range in which the edge points are used by the road parameter calculating unit to lie closer to the vehicle when the gradient detecting unit detects the change in gradient than when the gradient detecting unit does not detect the change in gradient.

A road parameter calculator comprising:

• an image acquiring unit which is configured to acquire an image of a forward view of a vehicle;
• an edge-point extracting unit which is configured to extract edge points from the image derived by the image acquiring unit;
• a road parameter calculating unit which is configured to calculate a road parameter through a Kalman filter using the edge points derived by the edge-point extracting unit, the road parameter representing a configuration of a road in front of the vehicle;
• a gradient detecting unit which is configured to detect a change in gradient of the road in front of the vehicle;
• and
• an edge-point limiting unit which is configured to define a right and a left range in which the edge points on a right and a left lane line are used by the road parameter calculating unit, the right and left lane lines being lines on the image which define a road on which the vehicle now exists, when the gradient detecting unit detects the change in gradient, the edge-point limiting unit setting the right and left ranges to be equal to each other.

A road parameter calculator comprising:

• an image acquiring unit which is configured to acquire an image of a forward view of a vehicle;
• an edge-point extracting unit which is configured to extract edge points from the image derived by the image acquiring unit;
• a road parameter calculating unit which is configured to calculate a road parameter through a Kalman filter using the edge points derived by the edge-point extracting unit, the road parameter representing a configuration of a road in front of the vehicle;
• a gradient detecting unit which is configured to detect a change in gradient of the road in front of the vehicle;
• a lane line producing unit which is configured to produce a lane line using the edge points derived by the edge-point extracting unit;
• a likelihood calculating unit which is configured to calculate a likelihood that the lane line, as derived by the lane line producing unit, is a branch line using at least one of a curvature, a yaw angle, and an offset of the vehicle lane line;
• a branch line determining unit which is configured to determine that the lane line represents the branch line when the likelihood, as derived by the likelihood calculating unit, is greater than a given threshold value;
• an edge-point removing unit which is configured to remove ones of the edge points which define the lane line, as determined by the branch line determining unit as being the branch line, from a range in which the edge points are used by the road parameter calculating unit;
• and
• a threshold determining unit which is configured to increase the threshold used when the gradient detecting unit detects the change in gradient to be greater than that when the gradient detecting unit does not detect the change in gradient.