1. An image processing device comprising: an integrating unit that acquires, from a camera installed on a movable body, images that are captured by the camera while the movable body is moving and integrates the acquired images so as to generate an integrated image; a vanishing-point identifying unit that extracts brightness edges from the integrated image and identifies an intersection point of lines determined by using the brightness edges as a vanishing point; and a determining unit that determines whether a parameter of the camera has an appropriate value by using coordinates of the vanishing point and reference coordinates.