Vehicle-applied rear-and-side monitoring system

Details Vehicle-applied rear-and-side monitoring system Vehicle-applied rear-and-side monitoring system

2001-10-22

2003-09-09

Arthur, Gertrude (Department: 3661)

Data processing: vehicles, navigation, and relative location

Relative location

Collision avoidance

C701S028000, C701S096000, C340S435000, C340S436000

Reexamination Certificate

active

06618672

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a vehicle-applied monitoring system and more particularly, to a vehicle-applied rear-and-side monitoring system which takes an image of a rear-and-side view of a running vehicle by means of an imaging apparatus such as a small-sized Charge Coupled Device (hereinafter CCD) mounted on the vehicle, detects a following vehicle in a the taken image, and gives a driver an alarm or the like indicating the approach of the following vehicle.
2. Description of Related Art
There exists dangerousness of a big traffic accident due to a dead angle area when a running vehicle changes a lane. For example, if a driver of a preceding vehicle executes a lane change without recognizing a following vehicle having entered the dead angle area, such a traffic accident as a collision would happen.
In order to prevent the above-described accident or dangerous situation, technology to make a driver accurately and surely recognize the existence of the following vehicle has been proposed.
For example, Japanese Patent Application Laid-open No. 1-189289 (hereinafter JP '289) discloses a vehicle information-display system which makes a driver recognize a vehicle running on th neighboring lane or at the back of the own vehicle. The prior art disclosed in JP '289 can makes a driver recognize a vehicle running on the neighboring lane or at the back of the own vehicle by taking an image of a rear-and-side view of the own vehicle with a camera and by showing the taken image on a monitoring display.
With respect to the above prior art, however, a driver has to watch the monitoring display carefully while driving so as to check the existence of a following vehicle, and further it would be difficult to judge whether the following vehicle is approaching the own vehicle or not.
Therefore, a vehicle-applied rearward monitoring system and vehicle-applied rearward monitoring method using this system have been proposed, wherein a relative speed, a relative distance, and/or a relative position between the own vehicle and the following vehicle running at the back of the own vehicle or on the neighboring lane are obtained by calculating a infinity point (or a disappearance point) which is generally called “Focus of Expansion” (hereinafter FOE), which FOE is a point where every points of an image taken by a video camera converge, by extracting a characteristic point from an image recognized as the following vehicle, and by calculating movement of the characteristic point. Hereinafter, the movement of the characteristic point is called optical flow.
Here, a rear monitoring method with the above conventional vehicle-applied rearward monitoring system will be briefly described below with reference to
FIGS. 9A and 9B
.
FIGS. 9A and 9B
are schematic views showing an example of sequential images of a rear-and-side view taken by a rearward monitoring camera, i.e., the image taking means, backward-lookingly mounting on a rear portion of the own vehicle and imaged on the image plane
1100
of an image sensor such as a CCD image sensor of the camera. In
FIGS. 9A and 9B
, the following vehicle
1101
is passing the own vehicle. Here, references numerals
1205
and
1207
indicate lane markings on the road.
First, referring to
FIG. 9A
, an image of the following vehicle
1101
is recognized in an image of a rearward view in the image plane
1100
.
Conventionally, a boundary, i.e., an edge, between an image of the following vehicle
1101
and images of the others such as the road, a background and the like (not shown), which are imaged on the image place
1100
, is recognized by making use of a luminance difference therebetween.
After recognition of the edge of the image of the following vehicle
1101
, the characteristic point A fitting to predetermined conditions is extracted by recognizing the edge or an area within the edge.
Further, at the next time-point, a corresponding point A′ is detected to form an optical flow connecting the points A and A′.
The degree of dangerousness of movement of the following vehicle
1101
is judged on the basis of the optical flow of the following vehicle
1101
. In case the following vehicle
1101
has been calculated to be in a dangerous position, an alarm is given to a driver to prevent the danger if fa direction indicator is put on.
With respect to the above conventional vehicle-applied rearward monitoring system, however, there is drawback mentioned below.
Here,
FIG. 7
is a schematic view showing an example of relative position between own vehicle
1103
running on the road
1202
and provided with the conventional vehicle-applied rearward monitoring system and the following vehicle
1101
. Reference numeral
1201
indicates a side area band of the own vehicle
1103
. And, reference numerals
1203
and
1204
indicate left and right traffic lanes, respectively, and reference numerals
1205
,
1206
, and
1207
indicate lane markings in the road
1202
. Further, reference character &thgr; indicates an image taking angle.
Referring to
FIG. 7
, in case that the following vehicle
1101
has entered a dead angle area
1200
of an image taking means
1104
mounted on the own vehicle
1103
, the following vehicle
1101
cannot be detected or calculated with the conventional vehicle-applied rearward monitoring system.
If the own vehicle
1103
executes a lane change when the following vehicle
1101
has entered the dead angle area
1200
, a big traffic accident, such as a collision, would happen.
SUMMARY OF THE INVENTION
In view of the foregoing, an object of the present invention is to provide a vehicle-applied rear-and-side monitoring system which can accurately and surely detect and calculate the existence of the following vehicle having entered a dead angle area of the own vehicle.
In order to achieve the above-described object, as a first aspect of the present invention, a vehicle-applied rear-and-side monitoring system of the present invention includes: an image taking means for taking an image of a rear-and-side view of an own vehicle being running on a lane; and a characteristic point extracting means for extracting at least one point as a characteristic point from an image of a following vehicle contained in a first image, taken at a first time-point, of the rear-and-side view, the following vehicle being running at the back of the own vehicle on the lane or on a neighboring lane of the lane; a corresponding point detecting means for detecting a corresponding point, corresponding to the characteristic point, in a second image taken at a second time-point following the first time-point; an optical flow forming means for forming an optical flow of the characteristic point of the following vehicle from a vector connecting the characteristic point and the corresponding point; and a dead angle area located vehicles-distance calculating means for calculating at least any one of a vehicles-distance between the own vehicle and the following vehicle and a relative position therebetween after a time-point of disappearance of the optical flow outside an image place of the image taking means on the basis of the optical flow formed just before the disappearance, wherein an approaching degree of the following vehicle being running at the back of the own vehicle on the lane or on the neighboring lane is monitored.
According to the above-described structure, by showing the calculated results of the vehicles-distance or the relative position on an image place of the displaying means using, for example, a liquid crystal display panel, a driver can surely recognize an existence of the following vehicle having entered the dead angle area of the own vehicle.
As a second aspect of the present invention, in the structure with the above first aspect, the dead angle area located vehicles-distance calculating means considers that the optical flow of the characteristic point of the following vehicle having arrived at a predetermined peripheral area of the image plane of the image taking means at the

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