1. An apparatus for detecting a position of an object in one or more images captured by an image pickup device mounted on a vehicle, comprising: (a) a memory configured to store a plurality of images captured by the image pickup device, wherein the image pickup device is a single camera, including a first image of an object taken at a first time by the single camera and a second image of the object captured at a second time by the single camera; and (b) a controller operatively coupled to the memory and configured to determine from the first image taken at the first time the position of the object and a first pitch angle of the vehicle relative to a y-coordinate in a horizontal direction is zero, and to determine from the second image whether a second pitch angle of the vehicle relative to the y-coordinate in the horizontal direction at the second time is zero, and to determine the position of the object in the second image based on the position of the object in the first image if the second pitch angle is not zero.