Vehicles are used both in conditions with good visibility, such as during the day, and in conditions with poor visibility, such as at night or in bad weather. Thus, in conditions where the visibility is good, the driver can see people and objects such as fallen objects around the vehicle by looking at the actual landscape with his or her (hereinafter, the driver will be referred to in the masculine form for simplicity) own eyes. In conditions where the visibility is poor, however, it is difficult for the driver to see all of these by looking the landscape. Hence, vehicle surroundings information output systems have been developed which inform the driver of the existence an object about which the driver is to be warned (hereinafter also referred to simply as “object”), such as a person or object around the vehicle.
Japanese Patent Application Publication No. JP-A-2003-291688, for example, describes one kind of vehicle surroundings information output system which is a so-called head-up display (HUD) that displays the landscape in front of the vehicle on the front windshield as both an object about which the driver is to be warned and a virtual image.
When an object is detected in front of the vehicle, the vehicle surroundings information output system (i.e., the head-up display system) described in Japanese Patent Application Publication No, JP-A-2003-291688 displays information (a solid star symbol) of strong visual stimulus to the driver and moves information (a triangular outline) to guide the driver's line of sight from that place to the object on the head-up display. That is, after an object is detected, the vehicle surroundings information output system described in Japanese Patent Application Publication No. JP-A-2003-291688 notifies the driver of the existence of that object by displaying information that stimulates the driver's vision (i.e., catches the driver's eye) and draws his line of sight to it (i.e., by displaying highly visually alluring information).
Also, other similar vehicle surroundings information output systems (head up display systems) which display such highly visually alluring information are described below.
Japanese Patent Application Publication No. JP-A-7-61257 describes a vehicle surroundings information output system which displays highly visually alluring information when the driver is not looking at the display of the head-up display and displays not so visually alluring information when the driver is looking at the display from the head-up display.
Japanese Patent Application Publication Nos. JP-A-2004-30212 and JP-A-2001-357498 describe vehicle surroundings information output systems which suppress the provision of information relating to a detected object as necessary. More specifically, Japanese Patent Application Publication No. JP-A-2004-30212 describes a vehicle surroundings information output system which prevents the driver from receiving more information than is necessary, thereby reducing the burden on the driver, by providing the minimum necessary information relating to objects while suppressing the provision of highly visible and visually alluring information relating to objects. Meanwhile, Japanese Patent Application Publication No. JP-A-2001-357498 describes a vehicle surroundings information output system which prevents the driver from receiving more information than is necessary, thereby reducing the burden on the driver, by suppressing information relating to objects near where the driver is looking.
Incidentally, Japanese Patent Application Publication No. JP-A-2000-251200 discloses an obstacle detection system structured such that warnings are issued more often when visibility of detected objects is poor than when it is good.
However, the vehicle surroundings information output system described in Japanese Patent Application Publication No. JP-A-2003-291688 provides the driver with high visually alluring information instantaneously after an object has been detected. That is, the head-up display displays highly visually alluring information when it is still unclear as to whether that object is real or not. Therefore, even if that object does not actually exist, the driver's eyes are still drawn to that highly visually alluring information. When the driver wants to drive by detecting objects on the actual landscape with his own eyes, his line of sight is forced from the actual landscape by the false information. The same can also be said for the vehicle surroundings information output system described in Japanese Patent Application Publication No. IP-A-7-61257 when highly visually alluring information is displayed when the driver is not looking at the head-up display.
In this case, even though these kinds of problems exist, if no information is provided to the driver until it is clear as to whether the object is real or not and that object happens to really exist, and further, if a warning has to be issued quickly, the notification to the driver of that object ends up being delayed. The same may also be said for the vehicle surroundings information output systems described in Japanese Patent Application Publication Nos. JP-A-2004-30212 and JP-A-2001-357498 when the provision of information regarding a detected object is suppressed as necessary because the driver feels it is annoying.
That is, despite the fact that some drivers want to drive giving priority to information obtained from the actual landscape while other drivers want to drive giving priority to information provided by the vehicle surroundings information output systems described above, these systems provide and suppress information relating to objects with disregard to the intentions of both kinds of drivers.