JPH11337643A - Rear monitoring system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the errors of determining a stationary object to be an approaching object, while constituting a rear direction sensor at low cost. SOLUTION: A rear sensor 2 outputs a plurality of wave motions for detection from the rear of own vehicle toward different regions and captures the reflected waves, in response to each of the wave motions for detection. Through this, the location of a wave motion reflecting point in the rear of own vehicle is detected, and an object in the rear of own vehicle is discriminated by an object discriminating means 6 on the basis of the continuity of information on the location of a wave motion reflecting point. Then the relative speed of the object discriminated by the object discriminating means 6 with respect to own vehicle is computed by determining means 7 and 8. On the basis of the relative speed, it is determined whether the object or not is an approaching object. A stationary object determining means 6c computes the length and width of the discriminated object from the information on the location of a wave motion reflecting point. When the object is determined to be a stationary object from the computed length and width, the object is excluded from the objects of computation for relative speed or is excluded from objects of the determination of approaching objects.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a moving object present behind a host vehicle in a vehicle such as an automobile.
The present invention relates to a rear monitor system for a vehicle.

[0002]

2. Description of the Related Art Conventionally, there has been known a rear monitor system for a vehicle which detects the presence of a moving object approaching from behind the host vehicle of a vehicle and alerts a driver.
In such a vehicle rear monitor system, a laser radar,
Position information of an object present behind the host vehicle is acquired by a rear sensor such as an ultrasonic sensor, and a relative speed of the object with respect to the host vehicle is calculated based on the position information. Then, it is determined whether or not the object is approaching the own vehicle based on the sign of the relative speed.

In other words, a detection wave such as a laser or an ultrasonic wave is output toward the rear of the host vehicle, and a reflected wave which responds to each detection wave is captured, whereby the position of the wave reflection point behind the host vehicle is detected. Can be detected. Then, the object is identified as a set of a plurality of wave reflection points, and the relative speed of the identified object with respect to the own vehicle is calculated,
If the relative speed is positive, it can be determined that such an object is approaching.

[0004] Based on such a determination result, the driver of the host vehicle is informed that an object (usually an automobile) is approaching from behind by a visual display such as an alarm lamp or an alarm buzzer, or an audio display. You can be notified by display.

[0005]

However, the ability of the rear sensor using the above-described wave to detect the position of the wave reflection point is not always constant, and a detection error occurs depending on the shape of the object to be detected and the surrounding environment. There are cases. The detection information of the rear sensor is used as the position information of the object, and if the relative speed is calculated based on the position information including this error, in some cases, the object may be determined to be an approaching object despite being a stationary object. There is.

As described above, detecting a stationary object as an approaching object provides erroneous information to the driver, lowering the reliability of the entire system,
It will make the driver feel uncomfortable. Therefore, it is necessary to appropriately evaluate the detection information obtained by the rear sensor and avoid erroneous determination based on information including a detection error.

Japanese Patent Application Laid-Open No. 9-91595 includes a plurality of types of rear sensors, such as a laser radar, a line sensor, and a rear camera, and compares the position information detected by each sensor with each other to determine a certain range. In Japanese Patent Application Laid-Open No. H11-163, a technique is disclosed in which when the objects are close to each other, they are put together as one group. According to this technique, it is possible to obtain accurate position information of the object by compensating for differences in detection capabilities of the sensors and detection errors.

However, in this technique, it is necessary to provide a plurality of types of rear sensors, so that the cost increases,
Also, the control may be complicated. The present invention
In consideration of the above-described problems, a rear sensor for a vehicle that can be configured at a low cost while avoiding erroneous determination as an approaching object in spite of being a stationary object while being configured at a low cost. It is intended to provide a monitor system.

[0009]

Therefore, in the vehicle rear monitor system of the present invention, a plurality of detection waves are output from the rear of the host vehicle to different regions by the rear sensor, and each detection wave is output. The position of the wave reflection point behind the host vehicle is detected by capturing the reflected wave that responds to the vehicle, and the object identification means identifies the object behind the host vehicle based on the detected information on the position of the wave reflection point. Then, the determining unit calculates a relative speed of the object identified by the object identifying unit with respect to the own vehicle, and determines whether the object is an approaching object based on the calculated relative speed.
Calculate the length and width of the object identified from the wave reflection point position information, and if the object is determined to be a stationary object from the calculated length and width, exclude the object from the calculation target of the relative velocity Or, it is excluded from the determination target of the approaching object.

Thus, it is possible to avoid erroneous determination of an approaching object despite being a stationary object.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a vehicle rear monitor system according to an embodiment of the present invention; FIG. As shown in FIG. 2, the rear monitor system for a vehicle includes a laser radar 2 as a rear sensor that detects an object existing behind the host vehicle at a predetermined position (for example, above a trunk lid) of a vehicle (automobile) 1. I have it. The laser radar 2 rotates within a predetermined cycle T (for example, 100 msec / rotation), and data, that is, laser light transmitted from the transmission unit of the laser radar 2 is reflected by an object at every predetermined rotation angle θ and received. The response time (wave reflection point position information) t before returning to the section is acquired. Here, it is assumed that the laser radar 2 rotates 180 degrees clockwise from the right side of the vehicle to the left side, and acquires data at each rotation angle from 0 degree to 180 degrees. For example, if θ = 1 degree, 181 data are acquired in one cycle, such as 0 degree, 1 degree, 2 degrees,.

The detection data obtained by the laser radar 2 is input to a control ECU 10 inside the vehicle 1. The instrument panel inside the vehicle 1 is provided with an alarm lamp 11 and an alarm buzzer 12 for controlling the control EC.
It lights up or emits an alarm in response to the output of U10. The configuration of the control ECU 10 will be described. As shown in FIG. 1, the control ECU 10 includes a laser radar communication unit 3, a laser radar control unit 4, a data conversion unit 5, an object recognition selection unit (object identification means) 6, and an object speed calculation. It comprises a unit 7, an alarm determination unit 8, and an output processing unit 9. The object speed calculation unit 7 and the alarm determination unit 8 constitute a determination unit.

The laser radar communication unit 3 includes a control ECU 10
Is an interface when communicating with the laser radar 2, and the laser radar control unit 4 has a function of controlling the scan cycle and timing of the laser radar 2,
The control is performed via the laser radar communication unit 4 so that the laser radar 2 acquires data at the above-described predetermined cycle T and the predetermined rotation angle θ.

The detection data obtained by the laser radar 2 is input to a data conversion unit 5 via a laser radar communication unit 4. The data converter 5 calculates the distance between the vehicle and the detection point based on the detection data acquired by the laser radar 2, that is, the response time t. Then, a relative position with respect to the host vehicle is calculated based on the calculated distance and rotation angle, and the position p of the detection point is plotted on a map represented by XY coordinates.

[0015] The object recognition selection unit 6 uses the data conversion unit 5 to execute X
An object existing behind the host vehicle is specified based on the detection point p represented on the Y map, and an object other than the stationary object is selected from the specified objects. Here, as shown in FIG. 3, as an example, a case in which a truck 20 is present on the right rear of the own vehicle 1 and a guardrail 21 is present on the left rear of the vehicle 1 will be described. A description will be given as to whether the track 21 is specified and only the track 20 is selected. Note that the host vehicle is traveling leftward in FIGS. 3 (a) to 3 (c).

First, the laser radar 2 changes the angle from 0 to 18 degrees.
Scan is performed for all rotation angles up to 0 degrees
At this time, at a rotation angle of nθ to (n + 7) θ,
Detection point p on track 20_n~ P_{n + 7}Detection data corresponding to
Data (response time t) is obtained, and mθ to (m + 8) θ
The detection point p on the guardrail 21 at the rotation angle_m~ P
_{m + 8}Detection data (response time t) corresponding to
Shall be.

[0017] Then, it is converted in the data conversion unit 5 in XY coordinates, as shown in FIG. 3 (a), all the detection points on the XY map _{p n ~p n + 7, p} m ~p m + 8 is When plotted, the object recognition selecting unit 6 sets a group of detection points on the XY map by the group setting unit 6A which is a functional element. The group setting by the group setting unit 6A is performed by grouping a plurality of detection points plotted on the XY map when there are detection points that are continuous within a predetermined distance and that belong to the same group. Do. Here, as shown in FIG. 3 (b), the detection point p _n ~p _{n + 7} consecutive detection point p _m ~p _{m + 8}
Belong to the same groups G ₁ and G ₂ , that is, they are regarded as the same object and are grouped.

All detected points p _{n to} p _{n + 7} , p on the XY map
_{When the} group setting is completed for _{m to} p _{m + 8} , the object recognition selecting unit 6 further detects the detection points set as a group by the shape specifying unit 6B and the stationary object determining unit (stationary object determining unit) 6C which are the functional elements. The shapes of the objects corresponding to the groups G ₁ and G ₂ are specified, and whether or not the objects are stationary objects is determined based on the specified shapes.

Firstly, the shape specifying unit 6B, FIG. 3 (b), the detection point p _n ~p _{n + 7} or detection point p _m ~p belonging to the group for each detection point group G _1, G _2
The minimum windows S ₁ and S _{2 in} which _{m + 8} are all included are set. Then, the length L and width W of the window are calculated from the coordinate values of the four corners of the set windows S ₁ and S ₂ , and the shape of the object corresponding to the detection point groups G ₁ and G ₂ is specified.

Here, the detected object is an automobile (for example,
In the case of a moving object such as a car or a truck), the window width W is equal to or greater than a certain reference width W ₀ , and the window length L is equal to or less than a certain reference length L ₀ . Objects having a width equal to or less than the reference width W ₀ or a length equal to or greater than the reference length L ₀ are apparently not moving objects, but are stationary objects such as guardrails and walls.

Therefore, the stationary object sorting section 6C calculates the calculated values.
Window length L, width W and reference length L₀, Reference width W₀
And the length L is the reference length L₀Bigger
Or the width W is equal to the reference width W₀If less,
The detection point group corresponding to the window is a stationary object.
Is determined. Here, the window S_TwoLength L_TwoBut
Reference length L₀Window S_TwoCompatible with
Detection point group G _TwoIs determined to be a stationary object.
You.

Each detection point on the XY map is set as a group.
And the group corresponding to the stationary object is identified
And the object recognition selecting unit 6 determines that the group
In other words, only the group corresponding to the moving object is
Select as processing target in relative speed calculation processing
It has become. Here, the detection point group G₁, G_Twoof
Among them, the detection point group G regarded as a stationary object_TwoIs excluded
And detection point group G ₁Is selected for processing
You. Thus, the guardrail 21 as a stationary object is
Excluded from the descending relative speed calculation process, only track 20
Is the processing target.

In the relative speed calculation section 7, the object recognition selection section 6
The relative speed of the processing target selected in (1) is calculated as follows. First, the relative speed calculation unit 7 determines whether or not the selected processing target exists in the warning area behind the host vehicle. This warning area
It means the range to be careful when the own vehicle changes lanes etc. when the moving object behind is approaching the own vehicle,
A certain range is set in advance on the XY map.
If a part of the detection points belonging to the detection point group to be processed is located in the alarm area, it is determined that the detection point group has entered the alarm area. Then, a relative speed with respect to the own vehicle is calculated for each detection point group that has entered the warning area.

The relative speed is calculated based on the amount of movement of the detection point group on the XY map. That is, since the position of the detection point p on the XY map is updated every scan cycle T of the laser radar 2, the position of the detection point group in the previous cycle is compared with the position of the detection point group in the current cycle, and The amount of movement of the detection point group between the points is determined and used as the relative speed.

[0025] In case of FIG. 3, if any of the detection points p _n ~p _n + ₇ is located within the alarm area, the detection point groups G ₁ determines that enters the warning area, each period calculating the relative speed seeking movement amount detection point group G ₁ on the XY map for each T. The warning determination means 8 determines whether or not to generate a warning based on the relative speed of the relative speeds of the detection point groups existing in the warning area calculated by the relative speed calculation unit 7. I have. That is, when the relative speed is greater than 0, it is determined that the moving object corresponding to the detection point group is approaching the own vehicle,
When the relative speed is 0 or less, it is determined that the moving object corresponding to the detection point group is running in parallel with the own vehicle or is moving away. When it is determined that the vehicle is approaching the vehicle, an alarm signal is output to the output processing unit 9.

In the output processing section 9, when an alarm signal from the alarm judging means 8 is inputted, an alarm sound is generated from an alarm buzzer 12 and an alarm lamp 11 provided in the instrument panel is turned on. . Alarm buzzer 12
Generates an alarm sound only for the first few seconds, and thereafter, only the alarm lamp 11 is turned on. FIG.
As shown in the figure, the warning lamp 11 is provided so that it can be grasped from which side of the vehicle the moving object is approaching.
LED lamps 1 on each of the left and right sides of symbol 15 showing the vehicle
1L and 11R are provided. The approach direction of the moving object is determined by referring to the Y coordinate value of the detection point group corresponding to the moving object on the XY map.

In the case of FIG. 3, when the truck 20 corresponding to the detection point group G ₁ approaches the host vehicle 1 in the alarm area, the alarm buzzer 12 emits an alarm sound and the right LED lamp 11R is turned on, and the driver is turned on. To inform that a moving object is approaching from the rear right. Since the vehicle rear monitor system as one embodiment of the present invention is configured as described above, for example, a moving object approaching from behind the host vehicle is detected by a control flow as shown in FIGS. .

First, as shown in FIG. 5, when starting the control, all data such as the position of the detection point p on the XY map is initialized (step S100). This process is performed only for the first time, and thereafter, the processes of steps S200 to S600 are repeated. Step S200 is
The control after step S300 is performed for a fixed period T (here, 1
00 msec), a timer (not shown) is counted, and when the timer value reaches 100 msec, the process proceeds to step S300. The timer value is cleared at the same time as counting 100 msec,
The count up to 00 msec is started.

In step S200, a fixed period (10
(0 msec) After the elapse of T, the laser radar control unit 4 rotates the laser radar 2 from 0 degree to 180 degrees, and acquires data on the object existing behind at every predetermined rotation angle θ (step S300). Then, based on the detection data acquired by the laser radar 2, it is determined whether or not a warning is issued for an object located behind (step S40).
0).

In this determination, as shown in FIG.
First, in the data conversion unit 5, the own vehicle at the detection point is detected based on the distance between the own vehicle and the detection point obtained from each detection data (response time) t acquired by the laser radar 2 and the rotation angle θ of the laser radar 2. XY is calculated.
The positions of the detection points are plotted on the map (step S4
10).

In the group setting section 6A of the object recognition selecting section 6, if there are continuous detection points among a plurality of detection points plotted on the XY map, they are regarded as belonging to the same group and grouped. (Step S420). When the group setting is completed for all the detection points on the XY map, the shape specifying unit 6B sets a minimum window including all the detection points belonging to the group for each detection point group,
The length L and width W of the window are calculated from the coordinate values of the corner.
In the stationary object determination unit 6C, when the calculated window length L is larger than the reference length L ₀ , or when the width W
If There reference width W ₀ is smaller than the detection point group corresponding to the window is determined to be a stationary object. The object recognition selecting unit 6 selects other detection point groups as processing targets in the next and subsequent steps (step S4).
30).

When the processing target is selected, the relative speed calculating section 7 first determines whether or not the detection point belonging to the detection point group to be processed is located in the alarm area (step S440). Then, for each detection point group that has entered the alarm area, the position of the detection point group in the previous cycle and the position of the detection point group in the current cycle are compared, and the movement amount of the detection point group during the cycle T is obtained. Thus, the relative speed to the own vehicle is calculated (step S450).

When the calculated relative speed is greater than 0, the alarm determination section 8 determines that a moving object corresponding to the detection point group is approaching the host vehicle and issues an alarm (step S460). . If it is determined that an alarm is to be issued, an alarm lamp 11 provided in the instrument panel
Is turned on (step S500), and at the same time, the alarm buzzer 1
2 generates an alarm sound (step S600).

As described above, according to the rear monitor system for a vehicle, it is determined that the object detected by the laser radar 2 does not clearly correspond to a moving object such as a car or a truck from the shape specified by the distribution of the detection points. In this case, an object that is actually a stationary object is determined to be a stationary object and is excluded from the calculation of the relative speed. Erroneous determination can be avoided. As a result, there is an advantage that the reliability of the entire system is improved and the driver does not feel uncomfortable.

Further, erroneous determination based on the detection error of the laser radar 2 is avoided, so that accurate determination can be performed at low cost without providing a plurality of rear sensors to improve the detection accuracy. is there. Furthermore, when it is determined that the object is a stationary object, the object is excluded from the processing target of the subsequent process such as calculation of the relative speed, so that there is an advantage that the load of the calculation processing is reduced and the processing time is shortened. .

It should be noted that the present invention is not limited to the above-described embodiment, and can be variously modified and implemented without departing from the gist of the present invention. By outputting and capturing the reflected wave that responds to the detection wave, it is sufficient if the position of the wave reflection point behind the host vehicle can be detected, and in addition to the laser radar as in the present embodiment, the ultrasonic wave Various detection means such as a sensor can be used.

In addition to the exclusion of the stationary object from the calculation of the relative speed, the stationary object may be excluded from the determination of the approaching object.

[0038]

As described in detail above, according to the rear monitor system for a vehicle of the present invention, it is determined that the object detected by the rear sensor does not clearly correspond to a moving object from the shape specified based on the detection information. In such cases, it is determined that the object is a stationary object and is excluded from the calculation of the relative speed, or is excluded from the object of the determination. That is, there is an advantage that the reliability of the entire system can be improved and the driver can be prevented from feeling uncomfortable.

Further, since an erroneous determination based on the detection error of the rear sensor is avoided, it is possible to accurately detect an approaching object at low cost without providing a plurality of rear sensors and improving the detection accuracy. There is also an advantage.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a configuration of a vehicle rear monitor system as one embodiment of the present invention.

FIG. 2 is a diagram showing an example of an arrangement on a vehicle of a vehicle rear monitor system as one embodiment of the present invention and a scan range of a rear sensor.

FIG. 3 is an explanatory diagram for describing identification of a stationary object according to the vehicle rear monitor system as one embodiment of the present invention, in which identification processing is performed in the order of (a) to (c).

FIG. 4 is a diagram showing a configuration example of an alarm lamp according to the vehicle rear monitor system as one embodiment of the present invention.

FIG. 5 is a flowchart illustrating an overall flow of an approaching object detection process of the vehicle rear monitor system as one embodiment of the present invention.

FIG. 6 is a flowchart illustrating a flow of a process of determining whether or not the vehicle is an approaching object in the vehicle rear monitor system according to the embodiment of the present invention;

[Explanation of symbols]

 Reference Signs List 2 laser radar (rear sensor) 6 object recognition selection unit (object identification unit) 6A group setting unit 6B shape specification unit 6C stationary object determination unit (still object determination unit) 7 relative speed calculation unit constituting determination unit 8 determination unit Alarm judging unit to be constituted 10 ECU 11 Alarm lamp 12 Alarm buzzer

Claims (1)

[Claims] 1. A rear part for detecting a position of a wave reflection point behind a host vehicle by outputting a plurality of detection waves toward different regions from behind the host vehicle and capturing reflected waves responding to the detection waves. A sensor, an object identifying means for identifying an object behind the host vehicle based on the wave reflection point position information detected by the rear sensor, and a relative speed of the object identified by the object identifying means with respect to the host vehicle is calculated. And determining means for determining whether or not the object is an approaching object based on the relative speed. The object identifying means determines the length and width of the identified object from the wave reflection point position information. And a stationary object discriminating means for discriminating whether or not the object is a stationary object from the calculated length and width is provided. The determining means determines that the object is a stationary object by the stationary object discriminating means. For objects, the relative speed Calculated either excluded from or characterized by excluding from the determination target 該接 near the object, the rear monitoring system for a vehicle.