ROAD SURFACE DETECTION DEVICE, OBJECT DETECTION DEVICE, OBJECT DETECTION SYSTEM, MOBILE OBJECT, AND OBJECT DETECTION METHOD

An object detection device includes a processor. The processor acquires or generates a first disparity image generated on the basis of an output of a stereo camera mounted in a mobile object. In the first disparity image, pixels representing disparities are arranged on a two-dimensional plane formed by a first direction corresponding to a base-length direction of the stereo camera and a second direction intersecting the first direction. The processor approximates a relationship between a coordinate, in the second direction, of a road surface in a direction of travel of the mobile object and a disparity representing the road surface with two straight lines, the relationship being included in the first disparity image.