In technologies for assisting rearward parking of a vehicle, there have been known a technology that captures an image by using a camera provided on a vehicle rear part, and displays the captured image on a display provided in the interior of the vehicle (so-called back monitor), and a technology that synthesizes images captured by cameras provided on the front, rear, left, and right sides of a vehicle to obtain a bird's-eye view, and displays the bird's-eye view on a display provided in the interior of the vehicle (so-called top-view monitor). There has been further proposed a parking assistance apparatus that captures images (images corresponding to side mirrors) by using cameras provided on the left and right sides of a vehicle to obtain images on the rear side of the vehicle, and adds the captured images to the left and right parts of a bird's-eye view shown on a display provided in the interior of the vehicle (see Patent Literature 1).
The inventor of the present application has found the following regarding a parking assistance apparatus for a vehicle.
When a vehicle moves rearward for rearward parking by using a back monitor, a parking frame starts to deviate from a field of vision of a camera in accordance with entrance of the vehicle into the parking frame. In this case, visual recognition of a positional relationship between the parking frame and the vehicle through the back monitor may become difficult for a driver of the vehicle. A top view monitor allows recognition of the positional relationship between the vehicle and the parking frame even after entrance of the vehicle into the parking frame. However, the image obtained by the top view monitor is not an image practically captured from immediately above the vehicle, but a synthesis image obtained by converting the captured images. In this case, a blind spot, that is, an area not visually recognizable, may be produced. As apparent from above, the method using only the back monitor or the bird's-eye view may be insufficient for securing visual recognition of a state in the rear of the vehicle.
According to a configuration described in Patent Literature 1 described above, for example, images corresponding to side mirrors need to be checked as well as a bird's-eye view. The images corresponding to the side mirrors are separately displayed on left and right displays. In this case, the left and right images displayed on the respective displays need to be alternately checked multiple times to park the vehicle equally on both sides within the parking frame. This problem may similarly arise from ordinary side mirrors.
In particular, for an inexperienced driver or the like not accustomed to rearward parking, it is often difficult to park a vehicle equally on the left and right sides of the parking frame at one try while gazing the images corresponding to side mirrors or both the side mirrors. Accordingly, the driver may be required to retry parking.