Communications: directive radio wave systems and devices (e.g. – Return signal controls external device – Radar mounted on and controls land vehicle
Reexamination Certificate
2001-04-25
2003-05-20
Gregory, Bernarr E. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Return signal controls external device
Radar mounted on and controls land vehicle
C367S087000, C180S167000, C180S168000, C180S169000, C342S195000
Reexamination Certificate
active
06567039
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an apparatus for recognizing the shape of a road which can be mounted on, for example, a vehicle. In addition, this invention relates to an on-vehicle apparatus for detecting a preceding vehicle. Furthermore, this invention relates to a recording medium which stores a computer program for recognizing the shape of a road.
2. Description of the Related Art
There is an on-vehicle apparatus for controlling the present vehicle to automatically maintain the distance between the present vehicle and a preceding vehicle in a safe range. In general, such an inter-vehicle distance control apparatus contains a radar device for measuring the distance to a preceding vehicle from the present vehicle and the speed of the preceding vehicle relative to the present vehicle. In the inter-vehicle distance control apparatus, an objective preceding vehicle for inter-vehicle distance control is selected from among candidate preceding vehicles detected via the radar device. It is desirable to accurately determine an objective preceding vehicle even when the present vehicle is traveling along a curved road. The recognition of a road shape is effective in accurate determination of an objective preceding vehicle.
Japanese patent application publication number 8-249598 discloses an on-vehicle apparatus for sensing delineators and recognizing a road shape from information about the sensed delineators. The apparatus in Japanese application 8-249598 emits a forward electromagnetic wave beam from the body of the vehicle, and controls the forward electromagnetic wave beam to periodically scan a given angular region (a detection area) in front of the body of the vehicle. In the case where an object exists in the given angular region (the detection area), the forward electromagnetic wave beam encounters the object before being at least partially reflected thereby. A portion of the reflected electromagnetic wave beam returns to the apparatus as an echo electromagnetic wave beam. The apparatus detects the object in response to the echo electromagnetic wave beam. Specifically, the apparatus calculates the distance to the object from the time interval between the moment of emission of the forward electromagnetic wave beam and the moment of reception of the related echo electromagnetic wave beam. In addition, the apparatus calculates the direction of the object relative to the vehicle.
The apparatus in Japanese application 8-249598 decides whether each detected object is a delineator on a right-hand road side or a delineator on a left-hand road side in response to the horizontal variation in the position of the object relative to the vehicle. Decided delineators on a right-hand road side are linked by lines, and the set of the lines is recognized as a right-hand road edge. Similarly, decided delineators on a left-hand road side are linked by lines, and the set of the lines is recognized as a left-hand road edge. The apparatus in Japanese application 8-249598 has a chance of erroneously detecting road edges in the case where the vehicle is traveling along a road provided with three or more rows of cat's-eyes.
Japanese patent application publication number 10-239436 discloses an apparatus for detecting the vehicle-to-vehicle distance. The apparatus in Japanese application 10-239436 emits a forward laser beam, and controls the forward laser beam to periodically scan a given angular region in front of the body of the present vehicle. The apparatus in Japanese application 10-239436 detects objects in the given angular range from return laser beams coming therefrom. Specifically, the apparatus detects the positions of the objects relative to the present vehicle. In more detail, the apparatus detects the distances to the objects and the directions (the angular positions) of the objects relative to the present vehicle. The detected objects include reflectors on the right-hand and left-hand sides of the road. In the apparatus of Japanese application 10-239436, the shape of the road is recognized from the loci (trajectories) of detected reflectors on the road sides. In addition, the range of the lane along which the present vehicle is traveling is calculated on the basis of the recognized road shape. Furthermore, a preceding vehicle is detected on the basis of the object positions relative to the present vehicle and the calculated range of the lane.
Japanese patent application publication number 6-68398 discloses an on-vehicle apparatus for detecting a road. The apparatus in Japanese application 6-68398 includes a radar device for emitting a forward electromagnetic wave beam, and controls the forward electromagnetic wave beam to periodically scan a given angular region in front of the body of the present vehicle. The radar device detects objects in the given angular range from return electromagnetic wave beams coming therefrom. Specifically, the radar device detects the positions of the objects relative to the present vehicle. The detected objects include reflectors on the right-hand and left-hand sides of the road, and reflectors on preceding vehicles. The apparatus of Japanese application 6-68398 estimates the shape of the road from at least one of 1) the positions of detected reflectors relative to the present vehicle and 2) the horizontal variations in the positions of the detected reflectors.
SUMMARY OF THE INVENTION
It is a first object of this invention to provide an improved apparatus for recognizing the shape of a road.
It is a second object of this invention to provide an improved on-vehicle apparatus for detecting a preceding vehicle.
It is a third object of this invention to provide a recording medium which stores an improved computer program for recognizing the shape of a road.
A first aspect of this invention provides a road-shape recognition apparatus comprising a radar device for emitting a detection wave ahead of a vehicle, and detecting objects in response to echoes of the emitted detection wave; reflector detecting means for detecting reflectors among the objects detected by the radar device, the reflectors being located along a road; reflector-row extracting means for, in cases where there are a plurality of rows of the reflectors detected by the reflector detecting means in one side of the vehicle, extracting one from among the reflector rows; and road-shape recognizing means for recognizing a shape of the road on the basis of the reflector row extracted by the reflector-row extracting means.
A second aspect of this invention is based on the first aspect thereof, and provides a road-shape recognition apparatus wherein the reflector-row extracting means comprises means for extracting one, which exists in a specified region with respect to the vehicle in a width-wise direction of the vehicle, from among the reflector rows.
A third aspect of this invention is based on the second aspect thereof, and provides a road-shape recognition apparatus wherein the reflector-row extracting means comprises means for setting the specified region in accordance with a width of a lane along which the vehicle is traveling.
A fourth aspect of this invention is based on the second aspect thereof, and provides a road-shape recognition apparatus wherein the reflector-row extracting means comprises position estimating means for estimating positions, in the width-wise direction of the vehicle, of the reflectors detected by the reflector detecting means which occur after a lapse of an arbitrary time; minimum position detecting means for detecting, among the positions estimated by the position estimating means, a minimum position corresponding to a position nearest to the vehicle; and means for setting the specified region on the basis of the minimum position detected by the minimum position detecting means.
A fifth aspect of this invention is based on the second aspect thereof, and provides a road-shape recognition apparatus wherein the reflector-row extracting means comprises position estimating means for estimating positions, in the width-wise dir
Morikawa Katsuhiro
Shirai Noriaki
Denso Corporation
Gregory Bernarr E.
Posz & Bethards, PLC
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