IMAGE PROCESSING DEVICE, IMAGE DISPLAY SYSTEM, AND IMAGE PROCESSING METHOD

PROBLEM TO BE SOLVED: To provide a technology that allows a driver to make an appropriate decision to change a lane.SOLUTION: An image acquisition unit 21 acquires a photographing image of a camera 5 mounted on an own vehicle 9, and an image generation unit 22 generates a surrounding image indicative of a surrounding area of the own vehicle 9 including an area shown on a side mirror of the own vehicle 9 on the basis of the photographing image. Further, a relative speed derivation unit 20b derives a relative speed of another vehicle running behind the own vehicle with respect to the own vehicle, and a guide line setting unit 20c determines a specified distance on the basis of the relative speed. An information superimposition unit 23 superimposes a varying guide line indicating a position of the specified distance backward from the own vehicle 9 on the surrounding image. And, an image input unit 24 outputs the surrounding image on which the varying guide line is superimposed to a display device 3 to be displayed. Thus, a driver of the own vehicle can grasp a safe positional relation between the own vehicle and another vehicle in accordance with the relative speed of another vehicle on the basis of the displayed surrounding image, and thereby the driver thereof can make an appropriate decision to change the lane.