Road surface detection device, object detection device, object detection system, mobile object, and object detection method

An object detection system comprising:

• a stereo camera that captures a plurality of images having a disparity therebetween;
• and
• an object detection device including at least one processor, wherein the processor is configured to:
• acquire or generate a first disparity map, the first disparity map being:
• generated based on an output of the stereo camera that captures an image including a road surface, and
• a map in which a disparity obtained from the output of the stereo camera is associated with two-dimensional coordinates formed by a first direction corresponding to a horizontal direction of the image captured by the stereo camera and a second direction intersecting the first direction,
• using two straight lines, approximate a relationship between a coordinate of the road surface in the second direction and a disparity representing the road surface, the relationship being included in the first disparity map, and
• detect an object using the disparity representing the road surface approximated using the straight lines,
• wherein the two straight lines include a first straight line and a second straight line,
• the processor approximates a short-distance side in a real space with respect to a side on which the stereo camera is located using the first straight line and approximates a long-distance side farther than the first straight line using the second straight line,
• the processor is configured to determine coordinates of an approximation start point in accordance with the first disparity map, the approximation start point being a point at which approximation using the second straight line is started on the long-distance side relative to the first straight line, and
• the processor is configured to determine the coordinates of the approximation start point based on an error between the first straight line and the disparity representing the road surface.

An object detection method comprising:

• acquiring or generating a first disparity map, the first disparity map being:
• generated based on an output of a stereo camera that captures an image including a road surface, and
• a map in which a disparity obtained from the output of the stereo camera is associated with two-dimensional coordinates formed by a first direction corresponding to a horizontal direction of the image captured by the stereo camera and a second direction intersecting the first direction;
• using two straight lines, approximating a relationship between a coordinate of the road surface in the second direction and a disparity representing the road surface, the relationship being included in the first disparity map;
• and
• detecting an object using the disparity representing the road surface approximated using the straight lines,
• wherein the two straight lines include a first straight line and a second straight line,
• the method further comprising:
• approximating a short-distance side in a real space with respect to a side on which the stereo camera is located using the first straight line and approximating a long-distance side farther than the first straight line using the second straight line, and
• determining coordinates of an approximation start point:
• in accordance with the first disparity map, the approximation start point being a point at which approximation using the second straight line is started on the long-distance side relative to the first straight line, and
• based on an error between the first straight line and the disparity representing the road surface.