JPH11337644A - Rear monitoring system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the errors of determining an object as an approaching object, even if it is not while constituting a rear 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 or not the object is an approaching object. At this time, a shape specifying means 6B specifies the shape of the object discriminated from the information on the location of a wave motion reflecting point by converting it into numerical form, and a change amount computing means 6C computes the amount of change in the numerical value indicating the specified shape in a predetermined time. At this time, determining means 7 and 8 either exclude the object with a predetermined amount or more of change in the numerical value indicating the shape from objects of the computation of relative speed or excludes the objects of the computation 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 may occur depending on the shape of the object to be detected and the surrounding environment. Or may contain noise. 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 the error and the noise, as if there is no approaching object, it is as if it exists. It may be determined, or in some cases, may be determined as an approaching object despite being a stationary object.

As described above, detecting an object that is not an approaching object as an approaching object provides erroneous information to the driver, lowers the reliability of the entire system, and gives the driver an uncomfortable feeling. Will be. Therefore, the detection information obtained by the rear sensor is appropriately evaluated,
It is necessary to avoid erroneous determinations based on information including detection errors and noise.

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 an object by compensating for differences in detection capabilities of respective sensors, detection errors, and effects of noise.

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
A rear monitor for a vehicle, which has been devised in view of the above-described problem, and which can configure a rear sensor at a low cost and can avoid erroneous determination as an approaching object even though the sensor is not an approaching object. The purpose is to provide a system.

[0009]

Therefore, in the vehicle rear monitor system according to the first aspect of the present invention, a plurality of detection waves are output from the rear sensor to different regions from behind the vehicle by using a rear sensor. The position of the wave reflection point behind the host vehicle is detected by capturing the reflected wave that responds to the detection wave, and the object behind the host vehicle is identified by the object identification means based on the detected information of the position of the wave reflection point. Then, the determining means calculates a relative speed of the object identified by the object identifying means with respect to the own vehicle, and determines whether the identified object is an approaching object based on the calculated relative speed.

At this time, the shape of the object identified from the wave reflection point position information by the shape specifying means is quantified and specified, and the change in the numerical value indicating the shape specified by the shape specifying means by the change amount calculating means during a predetermined time. When the amount is calculated, the determination unit excludes the object whose change amount of the numerical value indicating the calculated shape is equal to or more than a predetermined amount from the calculation target of the relative speed or the calculation target of the approaching object.

Further, in the vehicle rear monitor system according to the present invention, the change amount calculating means calculates not only the change amount of the numerical value indicating the shape in a predetermined time but also the change amount of the relative position of the object with respect to the own vehicle. Then, for an object in which either the change amount of the numerical value indicating the calculated shape or the change amount of the relative position is equal to or more than a predetermined amount, the determination unit excludes the object from the calculation of the relative speed, or the Exclude from calculation.

[0012] Thus, an object whose shape change amount is unnatural for an approaching object is excluded from the determination as to whether or not the object is an approaching object based on the relative speed. An erroneous determination can be avoided. Further, as means for quantifying the shape in the shape specifying means, a minimum rectangle including all wave reflection points corresponding to the identified object is set, and the width and length of the rectangle are calculated to calculate the shape. It may be digitized,
Thus, the shape of the identified object can be easily specified.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing 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 unit) 6, and a relative speed calculation. It comprises a unit 7, an alarm determination unit 8, and an output processing unit 9. The relative 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 own vehicle is calculated based on the calculated distance and the rotation angle, and the positions of the detection points are plotted on a map (XY map) represented by XY coordinates. In this XY map, the direction opposite to the traveling direction is the X-axis direction, and the right side of the host vehicle 1 is the Y-axis direction.

The object recognition selection unit 6 uses the data conversion unit 5
Based on the detection points represented on the Y map, identify the object existing behind the host vehicle, further exclude those that are not clearly approaching objects from the identified objects, and remove only those that are determined to be approaching objects. It is selected as a processing target of the relative speed calculation. Here, FIGS. 3A to 3C and FIG.
The details of the above processing in the object recognition selecting unit 6 will be described in detail with reference to FIG. The own vehicle is shown in FIGS.
(C), progressing to the left in FIG.

First, the laser radar 2 changes the angle from 0 degree to 18 degrees.
Scanning is performed for all rotation angles up to 0 degrees, and at this time, detection data (response time t) corresponding to detection points _{pn to pn + 7} at rotation angles of nθ to (n + 5) θ is obtained. Shall be. Then, the data conversion unit 5
Are converted to XY coordinates, and as shown in FIG. 3A, when all the detection points _{pn to pn + 5} are plotted on the XY map, the object recognition selecting unit 6 is a functional element thereof. The group setting unit 6A sets a group of detection points on the XY map.

The group setting by the group setting section 6A is performed in such a manner that a continuous detection point group among a plurality of detection points plotted on the XY map, that is, each detection point is obtained as continuous data, If there is a group of detected points whose distances are within a certain distance, they are regarded as belonging to the same group and are grouped. Here, as shown in FIG. 3B, the detection point p _n
Since ｐp _{n + 5} is continuous data and the distance between the detection points is also within a certain distance, they are grouped as belonging to the same group G, that is, the same object.

When the group setting is completed, the object recognition selecting section 6 further specifies the shape of the object corresponding to the detection point group G set as a group by the shape specifying section (shape specifying means) 6B which is a functional element thereof. It is supposed to. That is, as shown in FIG. 3C, first, regarding the detection point group G, detection points _{pn to pn + 5} belonging to the group.
Is set to the minimum window S in which all are included. Then, the length L and the width W of the window S are respectively calculated from the coordinate values of the four corners of the window S, and the shape of the object corresponding to the detection point group G is specified.

Here, the detected object is an automobile (for example,
In the case of a passenger car or a truck, the shape is always constant regardless of time. Therefore, the shape of the window S shown on the XY map is substantially constant regardless of time, or even if a detection error is considered. It is considered to be within a certain range. In other words, the change amounts ΔL and ΔW of the length L and width W of the window S during the control cycle T are within a certain range as long as the detected object is a normal moving object such as a car or a truck. You can think that there is.

Similarly, if the detected object is a normal moving object such as a car or a truck, there is a limit to the distance that can be moved within a fixed time, and the control period T of the window S represented on the XY map is limited. It is considered that the positional change amount ΔX (the amount of change in the X direction) and ΔY (the amount of change in the X direction) within the range also fall within a certain range. Therefore, the shape change amounts ΔL, ΔW of the window S and the position change amounts ΔX,
If ΔY is equal to or larger than the normally assumed change amount, the object detected in the current control cycle and the object detected in the previous control cycle cannot be determined to be the same object. As such a case, a case where noise is included in the detection data of the laser radar 2 or a case where a stationary object such as an implant or a signboard that is unstable is detected is considered.

Therefore, the object recognition selecting section 6 makes an identification judgment between the detected object and the object detected in the previous control cycle. Since the object is not an object, it is excluded from the target of the relative speed calculation process. More specifically, the object recognition selecting unit 6 first determines whether or not the detected processing target exists in the warning area behind the host vehicle before the identification determination. The warning area means a range to be noted when the own vehicle changes lanes or the like when a rearward moving object is approaching the own vehicle, and a predetermined 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. For example, FIG.
In the case of (c), when any of the detection points _{pn to pn + 5} is located in the alarm area, it is determined that the detection point group G has entered the alarm area, and The following identification determination is performed for each of the detection point groups that have entered.

As shown in FIG. 4, the object recognition selecting section 6
A change amount calculation unit (change amount calculation means) 6 which is a functional element thereof
In C, first, the window S set on the XY map in the current control cycle is compared with the window S ′ set in the previous control cycle, and the width change amount ΔW (ΔW = W−
W ′), a length change amount ΔL (ΔL = LL ′), and position change amounts ΔX and ΔY are calculated.

Each of the calculated change amounts ΔW, ΔL, ΔX, ΔY is calculated by the identification determining unit 6D, which is also a functional element.
The comparison preset threshold value a, b, c _x, respectively c _y, the amount of change ΔW, ΔL, ΔX, both the threshold value a of ΔY, b, c _x, is smaller than c _y, the current It is determined that the object detected in the control cycle and the object detected in the previous control cycle are the same object, and the amounts of change ΔW, ΔL, ΔX, Δ
Threshold a any one of the Y, b, c _x, equal to or greater than c _y, determines that not the same object.

Here, the thresholds a and b are respectively the width variation ΔW, which is set in consideration of the detection error of the laser radar 2.
Usually the maximum that can be assumed length variation [Delta] L, the threshold c _x, c _y is the maximum amount of positional change ΔX detected object is assumed when the normal of the moving object, corresponding to ΔY I have. The thresholds a and b may be fixed values as described above, or may be changed according to the width W and the length L.
Further, when a moving object such as a car or a truck is moving in a normal state, the relative position in the traveling direction changes greatly depending on the speed, but the change in the relative position in the lateral direction is smaller than that, so the Y direction threshold c _y is small, the threshold value c _x in the X direction is set slightly larger.

As described above, when the identification determination of the detected object in the current control cycle and the detected object in the previous control cycle is performed, the object recognition selecting unit 6 determines whether the identification determining unit 6D determines that the object is the same object. Only the detected object is selected as a target of the relative speed calculation processing. As a result, detection data that is obviously not considered to be of the approaching object is excluded from the target of the relative speed calculation processing, and only the detection object that is considered to be the approaching object is selected.

When the object to be processed is selected by the object recognition selecting section 6, the relative speed calculating section 7 calculates the relative speed based on the amount of movement of the detection point group corresponding to the selected processing object on the XY map. That is, since the position of the detection point 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,
The amount of movement of the detection point group during the period T is determined as the relative speed.

The alarm judging means 8 judges whether or not to issue an alarm based on the relative speed of the relative speeds of the detection point groups existing in the alarm area calculated by the relative speed calculating section 7. It has become. 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 host vehicle, and the relative speed is 0.
In the following cases, 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 determining 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. 3C, the detection point group G
When the object corresponding to approaches the host vehicle 1 in the alarm area, the alarm buzzer 12 emits an alarm sound and the right side L
The ED lamp 11R is turned on to notify the driver that a moving object is approaching from the rear right.
Since the vehicular 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 in a control flow as shown in FIGS. 6, 7 and 8. Is detected.

First, as shown in FIG. 6, when starting the control, all data such as the position of the detection point 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. In step S200, control after step S300 is performed for a fixed period T (here, 10
0 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 1
Cleared at the same time as counting 00msec,
The counting up to 0 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).

The determination in step S400 is made as shown in FIG. First, in the data conversion unit 5,
Each detection data acquired by the laser radar 2 (response time)
The relative position of the detection point with respect to the own vehicle is calculated based on the distance between the own vehicle and the detection point obtained from t and the rotation angle θ of the laser radar 2, and the position of the detection point is plotted on the XY map (step S410). .

Then, in the object recognition selecting section 6, first, when there is a continuous detection point among a plurality of detection points plotted on the XY map by the group setting section 6A,
They are grouped as if they belong to the same group. When the group setting is completed for all the detection points on the XY map, the shape specifying unit 6B sets a minimum window in which all the detection points belonging to the group are included for each detection point group, and corresponds to the detection point group. The shape of the object is specified (step S420).

When the group setting is completed for all the detection points,
When the shape specification of each detection point group is completed, it is next determined whether or not each detection point group is located in the alarm area (step S430). If it is determined that the detection point group is located in the alarm area, identification determination is performed for the detection point group (step S440).

This identification judgment is performed as shown in FIG. First, the change amount calculation unit 6C calculates the change amount ΔW of the width between the window set on the XY map in the previous control cycle and the window set in the current control cycle (step S441). Then, the identification determination unit 6D compares the change amount ΔW of the width calculated by the change amount calculation unit 6C with the threshold value a (step S442). The width variation ΔW is equal to the threshold a
In the above case, the detected object (target) in the previous control cycle and the detected object in the current control cycle are determined to be different objects, and are excluded from the calculation target of the relative speed (step S44).
8).

On the other hand, when the width change amount ΔW is smaller than the threshold value a, the change amount calculating section 6C determines whether the XY
The length change amount ΔL between the window set on the map and the window set in the current control cycle is calculated (step S443), and the identification determination unit 6D compares the calculated length change amount ΔL with the threshold value b. (Step S444). If the length change amount ΔL is equal to or larger than the threshold value b, the detected object in the previous control cycle and the detected object in the current control cycle are determined to be different objects, and are excluded from the calculation of the relative speed (step S44).
8) When the length change amount ΔL is smaller than the threshold value b,
The processing of step S445 is performed.

In step S445, the change amount calculating section 6C
Are the position change amount ΔX in the X direction (length direction) from the window set on the XY map in the previous control cycle to the window set in the current control cycle, and the Y direction (width direction).
And the position change amount ΔY. Then, the identification determination unit 6D first compares the position change amount ΔX in the X direction with the threshold value c _x (step S446), and determines that the position change amount ΔX is equal to the threshold value c x.
If smaller than _x , the position change amount in the Y direction Δ
Comparing the Y and the threshold c _y (step S447).

[0040] Then, if the position change amount ΔY or if the position change amount ΔX above threshold c _y is not less than the threshold value c _x, is the detection object and the detecting object of the current control period of the previous control cycle and another object It is determined and excluded from the calculation target of the relative speed (step S448). In this manner, only the detection point groups in which the width change amount ΔW, the length change amount ΔL, and the position change amounts ΔX, ΔY are smaller than the respective threshold _values a, b, c _x , and cy are set as the relative speed calculation targets. Select.

Referring again to FIG. 7, the relative speed calculation unit 7
When the detection point group for which the relative speed is to be calculated is selected, 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 detection point group is moved during the cycle T. By calculating the amount, the relative speed to the host vehicle is calculated (step S44).
0).

If 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 S450). . When it is determined that an alarm is issued (step S460), as shown in FIG.
The alarm lamp 11 provided in the instrument panel is turned on (step S500), and at the same time, an alarm sound is generated from the alarm buzzer 12 (step S600).

As described above, according to the rear monitor system for a vehicle, the length L and the width W of the object specified from the detection data of the laser radar 2 and the relative position with respect to the own vehicle are more than expected. If it changes greatly, it is decided that it does not correspond to a moving object such as a car or truck, and it is excluded from the calculation of the relative speed.
It is possible to avoid erroneously determining a stationary object whose detection of an implant, a signboard or the like is unstable as an approaching object, or erroneous determination based on noise information. As a result, there is an advantage that the reliability of the entire system is improved and the driver does not feel uncomfortable.

Further, in the rear monitor system for a vehicle, erroneous determination based on the detection error of the laser radar 2 is avoided, so that it is not necessary to improve the detection accuracy by providing a plurality of rear sensors, and it is possible to obtain an accurate and low cost. There is also an advantage that determination can be made. It is needless to say 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. For example, the rear sensor may be any sensor that can detect the position of a wave reflection point behind the host vehicle by outputting a detection wave and capturing a reflected wave that responds to the detection wave. The invention is not limited to the laser radar as in the embodiment, and various detection means such as an ultrasonic sensor can be used.

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

[0046]

As described above in detail, according to the vehicle rear monitor system of the first aspect, the numerical value indicating the shape of the detected object specified by the shape specifying means based on the detection information of the rear sensor. If the amount of change is larger than a predetermined amount set as a normally assumed amount, it is clearly determined that the vehicle does not correspond to a moving object such as a car or a truck, and is excluded from the calculation target of the relative speed, Alternatively, since the approaching object is excluded from the determination target, it is possible to avoid erroneously determining a stationary object whose detection is unstable as an approaching object or erroneous determination based on noise information. be able to. As a result, there is an advantage that the reliability of the entire system is improved and the driver does not feel uncomfortable.

Further, since 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. further,
According to the vehicle rear monitor system of the present invention, in addition to the case where the amount of change in the numerical value indicating the shape of the detected object changes more than a predetermined amount, the amount of change in the relative position of the detected object with respect to the own vehicle Even if the value changes more than a predetermined amount that is set as a normally assumed amount, it is excluded from the calculation target of the relative speed or is excluded from the determination target of the approaching object, so that the determination accuracy is Is improved,
Further, there is an advantage that the reliability of the entire system can be improved.

[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 a recognition process of a rear object according to the vehicle rear monitor system as one embodiment of the present invention, in which the recognition processes are performed in the order of (a) to (c).

FIG. 4 is an explanatory diagram for describing a rear object identification determination process according to the vehicular rear monitor system as one embodiment of the present invention;

FIG. 5 is a diagram showing an example of an arrangement of a warning lamp according to the vehicle rear monitor system as one embodiment of the present invention.

FIG. 6 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. 7 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;

FIG. 8 is a flowchart illustrating a flow of an identification determination process of the vehicle rear monitor system as one 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 (shape specification unit) 6C change amount calculation unit (change amount calculation unit) 6D identification judgment unit 7 constitutes judgment unit Relative speed calculating unit 8 alarm determining unit constituting the determining means 10 ECU 11 alarm lamp 12 alarm buzzer

Claims (2)

[Claims] 1. A rear detection unit that outputs a plurality of detection waves toward different regions from behind the host vehicle and captures reflected waves that respond to the detection waves, thereby detecting a wave reflection point position behind the host vehicle. 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 digitizes the shape of the identified object from the wave reflection point position information. A shape specifying means for specifying, and a change amount calculating means for calculating a change amount of a numerical value indicating the shape specified by the specifying means in a predetermined time are provided; and the determining means calculates the change amount by the change amount calculating means. The amount of change A rear monitor system for a vehicle, characterized in that an object whose amount is equal to or more than a fixed amount is excluded from a calculation target of the relative speed or is excluded from a determination target of the approaching object. 2. The change amount calculating means calculates a change amount of a numerical value indicating the shape of the object specified by the specifying means in a predetermined time, and calculates a change in a relative position of the object with respect to the own vehicle for a predetermined time. The determination means calculates an amount of change in the numerical value indicating the shape calculated by the change amount calculation means and the amount of change in the relative position of the object is equal to or more than a predetermined amount. 2. The vehicle rear monitor system according to claim 1, wherein is excluded from the calculation of the relative speed or the determination of the approaching object.