Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Traffic analysis or control of surface vehicle
Reexamination Certificate
1998-02-13
2001-04-03
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Traffic analysis or control of surface vehicle
C701S116000, C340S933000, C340S937000, C340S942000
Reexamination Certificate
active
06212468
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a system for detecting vehicles traveling along a plurality of lanes of a toll road.
In order to collect toll automatically at a tollgate to a toll road, it is necessary to detect any vehicle coming to or passing through the tollgate.
A vehicle detecting system is known which optically detects vehicles passing along the lanes of a toll road. As shown in
FIG. 1
, the system comprises a gantry
2
and a plurality of optical line sensors
3
a
to
3
g
. The gantry
2
straddles the toll road
1
, extending across the 3-lane toll road
1
. The line sensors
3
a
to
3
g
are attached to the lower side of the gantry
2
. The sensors
3
a
is located above the outer boundary of the lane
4
a
, the sensor
3
c
above the boundary between the lanes
4
a
and
4
b
, the sensor
3
e
above the boundary between the lanes
4
b
and
4
c
, and the sensor
3
g
above the outer boundary of the lane
4
c
. The sensors
3
b
,
3
d
and
3
f
are located above the center lines of the lanes
4
a
,
4
b
and
4
c
, respectively. On the surface of the road
1
, the view field
3
x
of each line sensor overlaps half the view field
3
x
of either adjacent sensor.
When no vehicles are under the gantry
2
, the line sensors
3
a
to
3
g
get the linear images of the surface of the road
1
at the right angle to the direction of the lanes and convert the linear images into video signals respectively. The video signals are stored in a memory device, so that the signals may be used as reference signals. In this case, above the line sensors can use one dimensional type TV cameras, as well as projecting/receiving light type sensors emitting and scanning light beam.
In operation, the line sensors
3
a
to
3
g
get the linear images of the surface of the road
1
, and convert them into video signals. These signals are compared with the reference signals to determine whether or not vehicles are on the toll road
1
. Assume a vehicle
5
is on the second lane
4
b
as shown in FIG.
2
. In this case, the signal generated by the sensor
3
d
located above the center line of the second lane
4
b
and the signals generated by the sensors
3
c
and
3
e
located on the sides of the sensor
3
d
are compared with the three reference signals generated by the sensors
3
d
,
3
c
and
3
e
. The basis of the difference between each signal and the corresponding reference signal is used to detect the vehicle
5
. In
FIG. 2
, S
1
, S
2
and S
3
represent the diagrammatically the signal differing sections where the signals generated by the line sensors
3
c
,
3
e
and
3
d
differ from the corresponding reference signals, respectively. The signal the sensor
3
d
generates when the vehicle
5
goes right below the sensor
3
d
has a signal differing section which is wider than the section representing the width of the vehicle
5
. By contrast, the signals the sensors
3
c
and
3
e
generate when the vehicle
5
travels right below the sensor
3
d
have a signal differing section which is just about half the section representing the width of the vehicle
5
. This is because the view fields
3
x
of the sensors
3
c
and
3
e
each overlap half the view field
3
x
of the sensor
3
d
on the surface of the road
1
and get the image of the vehicle
5
sideways. Hence, the width
6
of the vehicle
5
can be detected from a logical product of the signal differing sections S
1
, S
2
and the signal differing section S
3
.
Unless the width
6
of the vehicle
5
is extremely small, it can be accurately detected a logical product of the signal differing sections S
1
, S
2
and the section S
3
. Even the width of a motorcycle, which is relatively small, can be accurately detected unless the motorcycle is located right below any one of the line sensors
3
a
to
3
g.
But the conventional vehicle-detecting system may fail to detect a motor cycle, when a motorcycle
5
a
is traveling, almost along the center line of the lane
4
b
as is illustrated in
FIG. 3
, or virtually along the boundary between the view fields of the line sensors
3
c
and
3
e
. If this is the case, the signal differing section S
3
of the signal generated by the sensor
3
d
is large, but the sections S
1
and S
2
are very small since the widths of signal
7
detecting a motorcycle
5
a
by the sensors
3
c
and
3
e
are small. Consequently, the width
6
determined by processing the signals is therefore less than the actual width of the motor cycle
5
a
, or the motor cycle
5
a
may not be detected.
The system shown in
FIG. 1
may detects fallen leaves, trash or the like, which happen to be on the toll road
1
. In this case, the system generates and supplies a vehicle-detection signal, though no vehicles are passing under the gantry
2
. The vehicle-detecting system has but a low operating reliability.
Earth or sand may fall from a damp track onto the road
1
and may spread over the surface of the road
1
. The vehicle-detecting system detects the earth or sand and generates a false vehicle-detection signal. In view of this, too, the reliability of the conventional vehicle-detecting system is insufficient.
BRIEF SUMMARY OF THE INVENTION
The object of the present invention is to provide a vehicle-detecting system which can accurately measure the width of a vehicle, however slim the vehicle is, and which generates no false vehicle-detection signal when it detects a small thing on the road, such as a fallen leaf or trash, or a thing spread over the road, such as earth or sand, and which therefore has high operating reliability.
The foregoing object is accomplished by providing a system for optically detecting vehicles traveling a road having a plurality lanes, the system comprising:
a gantry provide at the road so as to straddle the plurality lanes;
a plurality of optical line sensors provided on the gantry, for getting linear images of a surface of the road, the optical line sensors arranged in two rows and in a staggered pattern such that each has a view field overlapping the view filed of either adjacent optical line sensor by the sum of half the view field and a width of a motor cycle;
photoelectric sensor apparatus consisting of photo-projector elements and photo-detector elements, and having optical axes which are parallel to each other and are substantially located in the position of the view fields of the optical line sensors; and
a signal-processing section for detecting a vehicle traveling under the gantry in accordance with output signals of the optical line sensors and output signals of the photoelectric sensor apparatus, by using reference signals which the optical line sensors generate when no vehicles travel under them.
With the present invention can provide the system, wherein the signal-processing section includes means for converting a correlation between the output signal of each optical line sensor and the corresponding reference signal into a binary signal, obtaining a logical sum of the binary signals pertaining to the optical line sensors of one row and a logical sum of the binary signals pertaining to the optical line sensors of the other row, obtaining a logical produce of the two logical sums, and determining, from the logical product, whether a vehicle is traveling under the gantry.
With the present invention can provide the system, wherein the signal-processing section includes means for converting a correlation between the output signal of each optical line sensor and the corresponding reference signal into a binary signal, obtaining a logical sum of the binary signals pertaining to the optical line sensors of one row and a logical sum of the binary signals pertaining to the optical line sensors of the other row, for obtaining a logical produce of the two logical sums, thereby generating a vehicle detection signal, and detecting a vehicle on the basis of the vehicle detection signal and vehicle detection signals generated by the photoelectric sensors.
With the present invention can provide the system, wherein the signal-processing section includes means f
Konishi Masayoshi
Nakayama Hiroyuki
Yamashita Riichiro
Cuchlinski Jr. William A.
Mitsubishi Heavy Industries Ltd.
To Tuan
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