An information processing device comprising: a road surface estimation unit configured to estimate a road surface in a parallax image captured using a stereo camera; a first generation unit configured to generate a first U-disparity map, which is first information in which a position of an object in a horizontal direction and a position of the object in a depth direction are associated with each other, from pixels of the parallax image which are in a first height range above the road surface, wherein the horizontal direction is a direction perpendicular to an optical axis of the stereo camera and the depth direction is a direction of the optical axis of the stereo camera; a first detection unit configured to detect one region in the parallax image indicating an object based on the first U-disparity map; a second generation unit configured to generate, from pixels of the parallax image which are in a second height range above the road surface, a second U-disparity map, which is second information in which the position of an object in the horizontal direction and the position of the object in the depth direction are associated with each other, wherein the second height range is a range of height larger than a predetermined value within the first height range; a second detection unit configured to detect a plurality of regions in the parallax image indicating objects based on the second U-disparity map; and an output unit configured to associate the one region detected based on the first information with the regions detected based on the second information as indicating the same object, and to output the one region and the regions that are associated with each other. a road surface estimation unit configured to estimate a road surface in a parallax image captured using a stereo camera; a first generation unit configured to generate a first U-disparity map, which is first information in which a position of an object in a horizontal direction and a position of the object in a depth direction are associated with each other, from pixels of the parallax image which are in a first height range above the road surface, wherein the horizontal direction is a direction perpendicular to an optical axis of the stereo camera and the depth direction is a direction of the optical axis of the stereo camera; a first detection unit configured to detect one region in the parallax image indicating an object based on the first U-disparity map; a second generation unit configured to generate, from pixels of the parallax image which are in a second height range above the road surface, a second U-disparity map, which is second information in which the position of an object in the horizontal direction and the position of the object in the depth direction are associated with each other, wherein the second height range is a range of height larger than a predetermined value within the first height range; a second detection unit configured to detect a plurality of regions in the parallax image indicating objects based on the second U-disparity map; and an output unit configured to associate the one region detected based on the first information with the regions detected based on the second information as indicating the same object, and to output the one region and the regions that are associated with each other.