Conventionally, as an image conversion application example of a side-view monitor system which is an example of a vehicle periphery monitoring system, constructing a system has been proposed, in which a driver more easily recognizes an image of a side camera by using a viewpoint conversion technology (see Japanese Patent Application Publication No. 2008-85691).
The purpose of the proposal is to eliminate a disparity caused from a difference between a viewpoint of the camera and that of the driver and to perform an image conversion so as to intuitively perceive a shape or the like.
That is, since the current camera for side-view monitor is provided inside of a side mirror, there is a disparity from the driver's viewpoint and a shape of an obstacle or the other object in the camera image is completely different from a shape which is viewed from a driver's seat. In a normal case, by being accustomed, the driver reconstitutes the camera image in his head and reconstructs and judges the positional relationship of the objects to be matched with the image viewed by the driver.
In such a case, in a case of the driver who is not accustomed or in an instant situation, a consistency between the image on the screen and the image viewed by the driver is degraded and a feeling of strangeness occurs. In order to solve the problems, in the above mentioned proposal, an image conversion of the camera image into an image (camera image) which is to be viewed by the driver is performed so as to minimize the influence.
Furthermore, as a feature of the expression method, it is supposed that a camera image is divided into two and an image conversion processing on each camera image is performed. More specifically, the image is divided into an image part of a vehicle which is included in the image and an image including an external blind part. The former is projected on a virtual vertical screen and converted into an image to be viewed from the driver's viewpoint, the latter is projected on a virtual horizontal screen and converted into an image to be viewed from the driver's viewpoint and the two images are superimposed and displayed.
As a result, the external blind image obtained by being converted into an image from the driver's viewpoint can be viewed through a semitransparent vehicle body. However, the semitransparent vehicle body image in this case is a mirror image of the vehicle body viewed from outside. As described above, the semitransparent vehicle image is implemented.
Even in the case of the mirror image, since the image of the actual vehicle body is superimposed, a size in forward and back directions, a sense for a distance and the like with respect to the viewpoint conversion image of the blind camera can be understood from a tire position and an image of a door. Therefore an intuitive perception can be effectively obtained and contribution to safe driving can be provided.
However, in specifically implementing the conventional side-view monitor system, there are the following problems of visibility.
That is, a semitransparent vehicle image is an actual vehicle image and a tire behavior and the like are actual movements and therefore high reliability with respect to response and the like can be provided. However, due to this viewpoint conversion method, the actual vehicle is converted to a form viewed from a back side and therefore the image is necessarily a mirror image and a direction of a turning angle of a handle is an opposite direction. That is, when turning right, the tire image turns left in a line-symmetrical manner and a feeling of strangeness occurs. This causes a problem that a sensory deviation becomes large when making consistency with an operation when turning due to use of the actual image.
The present invention is made while addressing the above problems and to provide a vehicle periphery monitoring system where, by matching a behavior of a semitransparent tire image to be superimposed with an operation from a driver's viewpoint, a feeling of strangeness is eliminated and intuitive space perception is assisted and also a vehicle moving direction and behavior can be easily perceived.