In a rendering device Urnd1, a CPU 7 receives a captured image each from two image capture devices 1 and 2. The CPU 7 then receives a steering angle of a steering wheel of a vehicle from a steering angle sensor 3. Based on the steering angle, the CPU 7 derives an estimated trajectory for the vehicle to take in the course of time. Then, with reference to the estimated trajectory, the CPU 7 selects several pixels each from the captured images, and then generates a drive assistant image based on those pixels. In this manner, the drive assistant image generated by the rendering device Urnd1 hardly causes the driver to feel strange.