Object detecting device

Details Object detecting device Object detecting device

1999-08-06

2001-03-20

Lee, Benjamin C. (Department: 2632)

Communications: electrical

Land vehicle alarms or indicators

Of relative distance from an obstacle

C340S904000, C180S169000, C250S559360, C250S559380, C250S221000, C356S004050, C342S070000, C342S052000, C342S107000, C342S146000, C377S006000

Reexamination Certificate

active

06204755

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an object detecting device for detecting an object by transmitting an electromagnetic wave comprising a laser or a millimeter wave to the object and receiving a reflected wave thereof.
2. Description of the Related Art
There is an object detecting device already proposed by the present assignee (see Japanese Patent Application No. 10-200035), which is designed to detect distances to targets T
1
, T
2
- - - and their lateral positions (vehicles traveling ahead of a vehicle) by vertically and laterally scanning with an electromagnetic wave transmitted forwards from a radar system mounted at a front portion of a vehicle V, and receiving a wave reflected by the targets T
1
, T
2
- - -, which device is included in the arrangement of
FIG. 6
showing an embodiment of the invention. In this object detecting device, the space for carrying out the detection of the targets T
1
, T
2
- - - is divided into a plurality of detection areas K
1
to K
15
having a width substantially equal to the lateral width of the vehicle V. Each of the detection areas K
1
to K
15
is divided into measure-shaped regions depending on the distance from the vehicle V by distance addresses [
1
] to [
200
], so that the distances to the targets T
1
, T
2
- - - and their lateral positions are detected based on a value resulting from the addition of signals indicative of reception levels of reflected waves in the measure-shaped regions.
In the above object detecting device, when reflectors R
2
, R
2
are not mounted on rear surfaces of the targets T
1
, T
2
- - -, the detected lateral widths of the targets T
1
, T
2
- - - are equal to the actual lateral widths of the targets T
1
, T
2
- - -. However, when highly reflective reflectors R
2
, R
2
are mounted on the rear surfaces of the targets T
1
, T
2
- - -, signals indicative of reception levels of the reflected waves in a region in which the reflectors R
2
, R
2
are included, are increased, and also signals indicative of reception levels of the reflected waves in a region around the reflectors R
2
, R
2
are increased. Therefore, there is a possibility that the lateral widths of the targets T
1
, T
2
- - - may be detected as values larger than the actual lateral widths of the targets T
1
, T
2
- - -.
When a plurality of targets T
1
, T
2
- - - having highly reflective reflectors R
2
, R
2
exist laterally adjacent one another at the same distance, or when highly reflective reflectors R
1
are mounted on a road and the reflectors R
1
and targets T
1
, T
2
- - - exist laterally adjacent one another at the same distance, there is a possibility that the targets T
1
, T
2
- - - may be merged together, or the targets T
1
, T
2
- - - and the reflectors R
1
on the road may be merged with each other, so that they may be detected as one target T
1
, T
2
having a large lateral width.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an object detecting device, wherein a plurality of objects existing laterally adjacent one another at the same distance can be prevented from being misdetected as a single object having a large lateral width in a merged manner.
To achieve the above object, according to a first aspect and feature of the present invention, there is provided an object detecting device for detecting an object in an object detecting area by transmitting an electromagnetic wave and receiving a reflected wave resulting from the reflection of the electromagnetic wave by the object, comprising a transmitting and receiving means for transmitting the electromagnetic wave and receiving the reflected wave in each of a plurality of small areas into which the object detecting area has been divided, a first storing means for storing the signals indicative of reception levels of the reflected waves from the small areas in accordance with the time lag from the transmission to the reception of the waves, a second storing means for storing signals indicative of reception levels of reflected waves in a plurality of detection areas in the form of the signals indicative of reception levels added together in accordance with the time lag from the transmission to the reception of the waves, the detection areas being defined by grouping adjacent ones of the plurality of small areas so as to have a predetermined lateral width, and an object detecting means for detecting a distance to the object, based on the result of comparison of an output from the first storing means with an output from the second storing means.
With the above arrangement, the output from the first storing means for storing the signals indicative of reception levels in the small areas without addition of them to provide a distance to an object which is easy to reflect the electromagnetic wave, is compared with the output from the second storing means for storing the signals indicative of reception levels in the small areas in the form of these signals added together in the detection area units to provide a distance to an object which is hard to reflect the electromagnetic wave, whereby the distance to the object is detected on the basis of the result of the comparison. Therefore, when a plurality of objects may be misdetected as a single object as a result of being merged together due to the output from the second storing means, the misdetection can be prevented by making up for the merging by the output from the first storing means, whereby the plurality of objects can be reliably detected in a discriminated manner.
The predetermined lateral width is set at 1.6 m in the disclosed embodiments, but such value is a matter for design, which can be changed properly depending on the size of an object to be detected. In a first embodiment, a beam transmitting section
1
, a transmitted-beam scanning section
2
, a beam receiving section
3
and a received-beam scanning section
4
form a transmitting and receiving means, and in a third embodiment, the beam transmitting section
1
, the transmitted-beam scanning section
2
, the beam receiving section
3
and a transmitted and received-beam scanning section
4
′ form a transmitting and receiving means.
According to a second aspect and feature of the present invention, the second storing means detects a lateral position of the object based on a lateral position of the detection area where the object has been detected.
With the above arrangement, the lateral position of each of the detection areas is previously determined in accordance with the collection of the small areas and hence, the lateral position of the object can be detected based on the lateral position of the detection area where the object has been detected.
According to a third aspect and feature of the present invention, the plurality of detection areas are defined in an overlapped pattern one on another by one half of the lateral width thereof.
With the above arrangement, since detection areas are defined in an overlapped pattern one on another by one half of the lateral width, even when an object exists in any lateral position, the object can be reliably detected in a cover-up manner in any detection area.
According to a fourth aspect and feature of the present invention, the second storing means extracts and outputs values exceeding a threshold value resulting from the addition of a plurality of signals indicative of reception levels in accordance with the time lag from the transmission to the reception of the electromagnetic wave.
With the above arrangement, since one of values resulting from the addition of a plurality of received signals in accordance with the time lag from the transmission to the reception of the electromagnetic wave, which exceeds a threshold value, is extracted, only an object providing a sufficiently large signal indicative of reception level of the reflected wave can be reliably detected in an extracted manner.
According to a fifth aspect and feature of the present invention, the transmitting and receiving means tra

Affiliated with

Also associated with

Rating

Object detecting device does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Object detecting device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Object detecting device will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2532053