JP3078761B2 - Object detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for judging the presence or absence, size and type of an object and projecting light to a detected object by projecting light emitted from a light source to a predetermined area and receiving the reflected light. The present invention relates to an object detection device for obtaining a distance and a direction, for example, an object detection device mounted on a vehicle or the like and used for detecting a preceding vehicle or an object installed on a road.

[0002]

2. Description of the Related Art As a detector of this type, there are a light emitting device as a light source for emitting light, a light emitting device for projecting light from the light emitting device toward an external predetermined detection target area, and a light reflecting device for reflecting light from an object. There is known a configuration in which a light receiving device that receives light is housed in a case, and the light is transmitted and received through a transparent glass or plastic (generally called a window) stretched over the case.

[0003] In this type of detection device, a situation may occur in which an object cannot be normally detected for some reason. The types of such abnormal detection states and their causes are as follows: (1) Nothing can be detected at all (causes: failure of the light emitting device, failure of the light receiving device, severe dirt on the entire window,
etc).

(2) A distant object cannot be detected (cause:
Deterioration of light emitting device, heavy rain, heavy fog, etc.).

(3) An object in a certain direction cannot be detected (cause: partial contamination of a window, failure of a light receiving device, etc.).

(4) The object in the direction of the edge in the detection target area cannot be detected (cause: dirt on the edge of the window, failure of the light emitting device, failure of the light receiving device, etc.). Something like can be considered. Therefore, there has been proposed an apparatus provided with a function of detecting dirt on a window or detecting deterioration or failure of a light emitting device.

[0007] For example, FIG.
3 is a device disclosed in Japanese Patent Application Publication No.
0, a light projecting device 130, an object detecting light receiving device 141, and an abnormality diagnosing light receiving device 142 are provided in a case 150. Further, the arithmetic and control unit 110 performs arithmetic processing for object detection based on the control of the light emitting device 120 and the light projecting device 130 and the signal from the object detection light receiving device 141, and the signal from the abnormality diagnosis light receiving device 142. An abnormality diagnosis unit 113 for performing an abnormality diagnosis is also provided in the case 150. The abnormality diagnosis unit 113 diagnoses dirt on the window 160 based on the light receiving level of the scattered reflected light at the window 160 received by the abnormality diagnosis light receiving device 142 and specular reflection at the window 160 received by the abnormality diagnosis light receiving device 142. The decrease in the light emission intensity of the light emitting unit 120 is diagnosed based on the light receiving level of the light.

[0008]

However, this device is
In order to judge an abnormal state due to contamination of a window or deterioration or failure of a light emitting unit, a light receiving device different from a light receiving device for detecting an object is further required. Therefore, in order to provide yet another light receiving device in addition to the light receiving device for object detection,
This leads to an increase in the volume of the device, an increase in cost, and an increase in the number of assembly steps.

Further, in this device, since the diffused light or the specular reflected light is received to determine the abnormal state, the position of the light receiving device for abnormality diagnosis is affected by the accuracy of assembly and the influence of vibration after assembly. If the relationship is deviated, there is a possibility that those reflected lights are not properly received and an accurate determination of an abnormal state cannot be made.

Further, when detecting an outdoor object, a state in which an object cannot be normally detected due to heavy rain or dense fog occurs. However, when an abnormal state due to heavy rain or dense fog is determined, heavy rain or dense fog is determined. A separate sensor is required to detect fog and dense fog, resulting in an increase in cost and complexity of the apparatus.

The present invention solves these problems in the prior art.

[0012]

According to the present invention, a light receiving state of a light receiving means for receiving reflected light from an object is monitored over time,
The above problem has been solved by employing means for judging a detection abnormal state in which an object cannot be normally detected based on the light receiving state.

As described above, the abnormal state of detection is determined by the light receiving means for object detection, so that one light receiving means can have two functions of object detection and abnormality detection. There is no need to provide them. Also, instead of using diffuse reflection light and specular reflection light, by using reflected light that is directly reflected from the object and returned,
An operation failure due to a slight displacement of the light receiving device or the like is also eliminated.

In the present invention, if the area of the light projected by the light projecting means is divided into a plurality of small areas and the state of receiving the reflected light from these small areas is monitored over time, the detection can be performed. It is possible to determine the abnormal state more finely. For example, if no reflected light is received from any of the plurality of small areas within a certain time, it can be determined that the cause is a failure of the light emitting element or the light receiving element.

Further, if the light projecting area is divided into a plurality of small areas in the direction of the distance to the object and monitored, abnormal detection due to a decrease in light emission intensity of the light emitting element or poor light reception due to heavy rain, dense fog, etc. Can be determined.

For example, if monitoring is performed separately in a long-distance region and other regions in the direction of distance to the object, if there is no reflected light from the long-distance region within a certain period of time, If there is reflected light from a region other than the above, it can be determined that the cause is a decrease in the emission intensity of the light emitting element.

On the other hand, if the light projecting area is divided into a medium distance area and a short distance area with respect to the direction of the distance to the object and the monitoring is performed, if the area is longer than the medium distance area within a certain period of time, If there is no reflected light and there is reflected light from a short distance area, it can be determined that the cause is poor light reception due to heavy rain or dense fog.

Further, if the light projecting area is divided into a plurality of small areas in the direction of the light projecting angle and the monitoring is performed, if there is no reflected light from a specific area within a certain time, other light is reflected. If there is light reflected from the area, it can be determined that the cause is contamination of the window corresponding to the direction of the specific area or deviation of the optical axis of the optical system.

Further, if the light projection area is divided into a plurality of small areas in the direction of the distance to the object, and the light projection area is divided into a plurality of small areas in the direction of the light projection, monitoring is performed. It is possible to determine all of the various types of abnormal states described above.

Further, in the present invention, the type of the detected abnormality is determined, so that appropriate control and corrective measures can be performed based on the determination result.

In the present invention, it is also possible to add a function for determining the distance and direction to an object by sweeping and projecting light.

Further, the detection abnormal state can be determined by using ultrasonic waves instead of light.

Next, the principle of the present invention will be described in more detail with reference to FIGS. Note that FIGS. 1 to 3 do not limit the present invention.

FIG. 1 is a diagram showing a basic configuration of the present invention. A is an object detection device of the present invention, and is mainly constituted by the following units 10 to 60. Numeral 10 denotes an arithmetic and control unit which outputs a signal for controlling each device and makes some judgment on an object based on a signal inputted from each device (judgment of presence / absence of an object, distance and direction of a detected object) Judgment, etc.). In addition, the arithmetic and control unit 10 includes a detection abnormality determination unit, and determines a detection abnormality state of each device. A light emitting device 20 includes a light emitting element. A light projecting device 30 projects light from the light emitting device 20 to the outside. A light receiving device 40 includes a light receiving element that receives light reflected from an object. Reference numeral 50 denotes a case, in which the light emitting device 20, the light projecting device 30, and the light receiving device 40 are housed. Reference numeral 60 denotes a light-transmitting window,
The light from the case 0 is projected on the window of the case 50 so that the reflected light from the object is received while the light from the outside is projected.

FIG. 2 is a diagram for explaining the basic principle of object detection according to the present invention. The object detection device A has an intensity E
Is projected in the range of the projection angle Θ. The maximum distance at which an object can be detected (the reflected light from the object can be detected as light from the object detection device A) is R, and depends on the intensity E of light emitted by the detection device A. The detection target area C in which an object can be detected is a hatched portion defined by Θ and R. If any object exists in the area C, the light projected from the object detection device A is reflected by the object and received by the light receiving device 40 of the object detection device A. The object detection device A determines the presence or absence of an object in the arithmetic and control unit 10 based on the reflected light from the detection target area C, and obtains the direction in which the object exists, the distance to the object, and the like.

When the object detecting device A of the present invention is used, for example, mounted on a vehicle, a roadside reflector,
Objects to be detected such as a center line reflector, a road sign, a signboard, and other roadside objects are present, and these objects to be detected and the object detection device A relatively move.
Accordingly, a large number of detected objects enter and exit the detection target area C of the object detection device A.

FIG. 3 is a view for explaining the basic principle of the detection abnormality judgment in the present invention. Xn (n = 1, 2,
...) are moving objects. As described above, if the area C is continuously monitored by, for example, the object detection device A mounted on the vehicle, a large number of objects Xn should be detected and move in and out of the area C. In order to enter or leave the area C, it is necessary to cross one of the small areas C1, C2, and C3 in the area C, and if these small areas are continuously monitored, the reflected light from the object is inevitable. Should be received. The same applies to the small area C4. If the small area C4 is continuously monitored for a certain period of time or more, there must be an object that crosses the small area C4. It should be received.

The present invention has been made based on such a viewpoint, and the fact that reflected light is not received from a specific area for a long time means that an object cannot be detected normally. It is assumed that a state (some abnormality / failure, heavy rain / fog) has occurred. Then, the light receiving state of the reflected light in a specific area is monitored over time, and the abnormal detection state is determined based on how the reflected light is received. That is, the object detection device of the present invention utilizes the original function of receiving reflected light of the object detection device and detecting an object, and monitors the manner in which the reflected light is received over time to obtain an object. Is to determine a detection abnormal state that cannot be detected normally.

Therefore, the object detecting device of the present invention does not require a light receiving device for judging a detection abnormal state other than the object detecting function, and has a function of monitoring the light receiving state of the reflected light in the original configuration of the object detecting device. The detection abnormal state can be determined only by adding.

[0030]

Embodiments of the present invention will be described below.

FIG. 4 is a diagram showing the configuration of the object detection device, and is a diagram that embodies FIG. The object detecting device A includes an arithmetic and control unit 10, a light emitting device 20, a light projecting device 30, a light receiving device 40, a case 50, and a translucent window 60.

The arithmetic and control unit 10 includes a control unit 11, an arithmetic unit 12, and a detection abnormality determination unit 13.

The light emitting device 20 includes a laser diode 21,
A collimating lens 22 is included. The laser diode 21 is pulse-driven by a signal from the control unit 11,
Pulse emission is performed at a fixed time interval of the number of times of emission N = 80 times / 0.1 s. Then, the pulsed laser light is emitted from the light emitting device 20 through the collimating lens 22.

The light projecting device 30 includes a rotating mirror 31, a motor 32, and a cylindrical lens 33. The turning mirror 31 is driven by a motor 32 in response to a signal from the control unit 11 and turns within a range of an angle Θ = 0.2 rad. Further, a signal related to the rotation angle of the rotation mirror 31 is sent from the angle detection unit (not shown) to the control unit 11. Angle Θ
The time required for one rotation in the range of = 0.2 rad is 0.1 s. That is, the rotation mirror 31 has the period T
= 0.1 s, the rotation in the range of the angle Θ = 0.2 rad is repeated. The pulse laser light emitted from the light emitting device 20 is
The cylindrical lens 3 after being reflected by the rotating mirror 31
3 and is further projected outside through a translucent window 60. The laser light projected to the outside is swept and projected within the range of the projection angle Θ by the function of the rotating mirror 31. The laser light projected to the outside is formed into a fan shape having a thin angle in the projection angle Θ direction (sweep direction) and a divergence angle Φ in the direction perpendicular to the projection angle Θ direction by the action of the collimating lens 22 and the cylindrical lens 33. The light is converted and emitted.

FIG. 5 is an explanatory diagram of a detection target area of the object detection device A. The object detecting device A is a light emitting device 3
By the function of 0, a fan-shaped light having a divergence angle Φ (for example, about 0.015 rad) which is thin in the sweeping direction and perpendicular to the sweeping direction is projected. The rotation mirror 31 has an angle Θ = 0.2r
The ad is rotated at 0.1 s, and the laser light is emitted 80 times during the 0.1 s. Therefore, the object detection device A sweeps and projects the range of the projection angle Θ with the laser beam of 80 shots in 0.1 s, and 0.025 ra within the range of the projection angle Θ.
The laser beam is projected once every d. The maximum detection distance is R (for example, about 100 m). An area C surrounded by a dotted line is a detection target area. If an object (having a high reflectance) exists in this area C, the object can be detected by receiving reflected laser light from the object.

Returning to FIG. 4, the light receiving device 40 includes a light receiving lens 41 and a photodiode 42. If an object exists in the detection target area C, the laser light from the light emitting device 30 is reflected by the object. The reflected laser light is
The light enters through the light-transmitting window 60, passes through the light receiving lens 41, and is received by the photodiode 42. The photodiode 41 transmits a light receiving signal to the control unit 11.

The arithmetic and control unit 10 includes a control unit 11, an arithmetic unit 12, and a detection abnormality determination unit 13. Control unit 11
Outputs a drive signal for pulse emission to the laser diode 21 and transmits a start signal to the calculation unit 12.
At the same time, the control unit 11 takes in the rotation angle (= corresponding to the projection direction of the laser beam) of the rotation mirror 31 from the angle detection unit (not shown). The laser diode 21 emits a laser beam in response to the drive signal, and the laser beam is emitted from the object detection device A in a direction corresponding to the rotation angle of the rotation mirror 31 at that time.

If an object exists in the direction in which the laser light is projected, the laser light is reflected, and the reflected laser light is reflected by the object detecting device A.
Incident on. The reflected laser light is received by the photodiode 42 through the translucent window 60,
Transmits a light reception signal to the control unit 11. Control unit 11
Receives the input of the light receiving signal and transmits a stop signal to the arithmetic unit 12. The calculation unit 12 measures the time Δt from the input of the start signal to the input of the stop signal, and calculates r = (Δt · light speed) / 2 using Δt and the light speed c. The control unit 11 obtains the starting point x (r, θ) of the reflected laser light by taking in the value of r from the arithmetic control unit 12 and taking in the projection direction θ of the laser light from the angle detection unit.
The control unit 11 stores the starting point x (r, θ) of the reflected laser light and transmits the same to the detection abnormality determination unit 13. Then, the control unit 11 outputs a drive signal for the next pulse emission to the laser diode 21 and repeats the same processing.

On the other hand, if there is no object in the direction in which the laser light is projected, the laser light is not reflected, and the reflected laser light does not enter the object detection device A. Therefore, no light receiving signal is transmitted from the photodiode 42 to the control unit 11. The control unit 11 sets r = な け れ ば if no light receiving signal is input, and obtains the starting point x of the reflected laser light by taking in the projection direction θ of the laser light from the angle detection unit.
(R, θ) is obtained (here, r = ∞, indicating that no reflected light was received). The control unit 11
The start point x (r (= ∞), θ) of the reflected laser light is stored and transmitted to the detection abnormality determination unit 13. And
Control unit 11 outputs a drive signal for the next pulse emission to laser diode 21 and repeats the same processing.

With the projection of the laser beam 80 times during 0.1 s, the detection target area C in the range of the projection angle Θ = 0.2 rad was swept once, and the starting point of 80 reflected laser beams x (r, θ) is obtained. The control unit 11 determines which of the starting points x is one object, and determines the number of objects, the direction, distance, size, and the like of each object. In addition, the moving direction and moving speed of the object are also determined together with the result of the previous sweep. According to the use of the object detection device, necessary results are displayed or transmitted to a host system or a controlled system in accordance with the use of the object detection device.

On the other hand, the detection abnormality judging section 13
Based on the starting point x (r, θ) of the reflected laser light sent from the controller 1, a detection abnormality is determined. Detection abnormality judgment unit 13
Divides the detection target area C into a plurality of small areas Cij, and receives the reflected laser light in each of the small areas Cij (that is, detects the starting point x (r, θ) of the reflected laser light). ) Is monitored to determine the detection abnormality. When it is determined that a detection abnormality has occurred, a signal is transmitted from the detection abnormality determination unit 13 to the control unit 11, and a signal or a warning corresponding to the type of the detection abnormality is performed based on the signal from the control unit 11, Instruct the coping method or stop the object detection operation.

FIG. 6A shows a specific area monitored by the detection abnormality judging unit 13. Detection abnormality judgment unit 1
3 divides the detection target area C into eight in the direction of the distance R (i = 1, 2,
…, 8), divided into 6 parts in the direction of the projection angle Θ (j = 1,2,…, 6)
It is divided into a total of 48 small areas Cij, and these small areas Cij
The state of detection of the starting point x (r, θ) is monitored for each of them, and a detection abnormality is determined.

For each detection of the laser beam, the starting point x (r, θ) of the reflected laser beam is sent to the detection abnormality determination section 13.
(If the reflected laser light is not received, r = ∞) is sent from the control unit 11. The detection abnormality determination unit 13 checks in which small area Cij the starting point x (r, θ) sequentially sent from the control unit 11 for one sweep (80 light projections). I do. Furthermore, for the next sweep,
Similarly, it is checked in which small area Cij the starting point x (r, θ) exists. By repeating this process, the detection abnormality judging section 13 monitors the presence or absence of the starting point x (r, θ) of the reflected laser light in each small area Cij over time. The detection abnormality determination unit 13 determines four types of detection abnormal states.

The first type of detection abnormality is determined at the starting point x in the 48 small areas Cij (i = 1, 2,..., 8; j = 1, 2,..., 6) shown in FIG. The determination is made based on the existence state. The detection abnormality judging unit 13 determines that 10 seconds or more (therefore, N1 = 1)
If the state where the starting point x does not exist in all the small areas Cij (for the 00 sweeps), it is determined that the first type of detection abnormality has occurred. It cannot be considered that the starting point x does not exist in any of the small areas Cij in a normal state, and the light emitting device 20 or the light receiving element 3 is out of order or the translucent window 60 is very dirty. Therefore, the reflected laser light from the object may not be properly received. Thus, a state in which no starting point x exists in any of the small areas Cij is determined as a first type detection abnormal state, and the detection abnormality determination unit 13 sends a signal to the control unit 11. The control unit 11 receives a signal from the detection abnormality determination unit 13 and notifies the occurrence of the first type detection abnormality by means (not shown).

As shown in FIG. 6B, the second type of detection abnormality is determined by 48 small areas Cij (i = 1, 2,..., 8; j = 1, 2,
.., 6) are divided into a small area C8j, i = 8, which is a long distance area, and a small area Cex other than the small area, and the determination is made based on the existence state of the starting point x in these two small areas. The detection abnormality determination unit 13 determines that the detection error is 300 s or more (therefore, N2
If the starting point x does not exist in the small area C8j (for 3000 sweeps) and the starting point x exists in the small area Cex for 300 s, a second type of detection abnormality occurs. Judge that Despite the existence of the starting point x in the middle and short distance area, a long distance (i =
8), the starting point x does not exist for a long time.
It is conceivable that the reflected laser light from the object was not properly received because the laser diode deteriorated and the light emission intensity decreased. As described above, a state in which the starting point x exists only in the medium-to-near-distance region and the starting point x does not exist in the long-distance region is determined to be the second type of abnormal detection state. Send. The control unit 11 includes the detection abnormality determination unit 1
Receiving the signal from 3, the detection operation of the object is continuously executed, and the occurrence of the second type detection abnormality is notified by means (not shown).

As shown in FIG. 6 (c), the determination of the third type of detection abnormality is performed by 48 small areas Cij (i = 1, 2,..., 8; j = 1, 2,
.., 6) are converted into small areas Ci1 with j = 1 and small areas Ci2 and j with j = 2.
= 3, a small region Ci4 of j = 4, a small region Ci5 of j = 5, a small region Ci6 of j = 6, and a starting point x in these six small regions. The determination is made based on the existence state. For example, focusing on the small region Ci1, the starting point x does not exist in the small region Ci1 for 60 s or more (accordingly, for N3 = 600 sweeps).
s, the other five small areas Ci2, Ci3, Ci4, Ci5, C
If the starting point x exists in i6, it is determined that a third type of detection abnormality has occurred. Also, for example, a small area Ci4
, The starting point x in the small area Ci4 for 60 seconds or more
Does not exist, and the other five small areas Ci1,
Even when the starting point x exists at Ci2, Ci3, Ci5, and Ci6, it is determined that the third type of detection abnormality has occurred. The same applies to other small areas.

The reason that the starting point x does not exist only in a certain direction despite the existence of the starting point x in another direction is that the window corresponding to that direction is dirty or the optical axis of the optical system is shifted. Therefore, it is considered that the reflected laser light from that direction cannot be properly received. Thus, a state where the starting point x exists in the other direction and the starting point x does not exist only in one direction is determined as a third type detection abnormal state, and the detection abnormality determining unit 13 sends a signal to the control unit 11. Control unit 1
1 receives the signal from the detection abnormality determination unit 13 and continuously executes the object detection operation, and notifies the occurrence of the third type detection abnormality by means (not shown).

When an outdoor object is detected, a fourth type of detection abnormality is determined. As shown in FIG. 6D, the determination of the fourth type of detection abnormality is performed by using 48 small areas Cij.
(I = 1, 2,..., 8; j = 1, 2,..., 6) to C5j to C8j
And a small area Cne including short distances C1j to C4j, and the determination is made based on the existence state of the starting point x in these two small areas. The detection abnormality determination unit 13 determines that the starting point does not exist in the small area Cfa for 30 s or more (for N4 = 300 sweeps), and the starting point x exists in the small area Cne during the 30 s. In this case, it is determined that a fourth type detection abnormality has occurred. Despite the fact that the starting point x exists in the short distance area, the starting point x does not exist in the area of the middle distance or more (i = 5 to 8) over the range of the projection angle Θ -It is considered that the reflected laser light was not properly received due to the dense fog. In this way, a state in which the starting point x exists only in the short distance area and the starting point x does not exist in the middle and long distance area is determined as a fourth type of detection abnormal state, and the detection abnormality determination unit 13 sends a signal to the control unit 11. The control unit 11 receives the signal from the detection abnormality determination unit 13 and continuously executes the object detection operation, and notifies the occurrence of the fourth type detection abnormality by means (not shown). Then, the detection abnormality determination unit 13 continuously monitors the detection state of the object, and sends a signal to the control unit 11 when the detection abnormality is resolved. The control unit 11
In response to the signal from the detection abnormality determination unit 13, the notification of the detection abnormality performed by means (not shown) is stopped.

FIG. 7 is a diagram for explaining the flow of the object detection processing and the detection abnormality determination processing. T1, T2, T3
(J) (j = 1 to 6) and T4 are variables representing the number of sweeps (elapsed time) in the determination of the first to fourth types of detection abnormalities, respectively. E1, E2, E3 (j) (j = 1 to
6) and E4 are variables indicating whether or not the starting point x of the reflected laser light exists in the target small area in the determination of the first to fourth types of detection abnormalities, respectively. This is a variable that is represented by “1” when it is performed and represented by “0” when it does not exist. n is a variable representing the number of times of irradiation of the pulse laser light. x (n) (n = 1 to 80) is data representing the position of the starting point of the reflected laser light obtained for the n-th light projection.

First, in ST1, T1, T2, T3
(J) (j = 1 to 6), the values of T4 are “0”, E
The values of 1, E2, E3 (j) (j = 1 to 6) and E4 are also “0”. In ST2, since it is the first sweep, the values of T1, T2,
A value of “1” is given to each of T3 (j) (j = 1 to 6) and T4. In ST3, the value of the number of light projections n is set to “0”.
And

The repetition of n = 80 times from ST4 to ST15 is the flow of processing in one sweep. ST
In 4, the value of n is incremented by 1 to become "1", and the first laser light is emitted. In ST5, it is determined whether or not reflected light for the laser light has been received. If reflected light is received, r is calculated, and if reflected light is not received, r = ∞,
Then, the values of r and θ are used as the starting position x (n) = (r,
θ).

In ST6, it is determined whether or not r = ∞. If r = ∞, since the starting point x (n) does not exist in the detection target area C, the process proceeds to ST15 with the values of E1, E2, E3, and E4 each being “0”. If not r = ∞, since the starting point x (n) exists in the detection target area C,
1 = 1, and it is determined in which small area Cij the starting point x (n) exists after ST7.

In ST7, it is determined whether or not the starting point x (n) exists in the small area C8j.
The process proceeds to T8, and if not, proceeds to ST8 with E2 = 0.

In ST8, it is determined whether or not the starting point x (n) exists in the small area Ci1, and if it exists, the process proceeds to ST14 with E3 (1) = 1, and if not, E3 (1) = 0 remains. Proceed to ST9. In ST9, it is determined whether or not the starting point x (n) exists in the small area Ci2.
(2) = 1 and the process proceeds to ST14.
The process proceeds to ST10 with (2) = 0. In ST10, it is determined whether or not the starting point x (n) exists in the small area Ci3. If it exists, the process proceeds to ST14 with E3 (3) = 1, and if not, the process proceeds to ST11 with E3 (3) = 0. move on. ST
At 11, it is determined whether or not the starting point x (n) exists in the small area Ci4. If there is, the process proceeds to ST14 with E3 (4) = 1, and if not, the process proceeds to ST12 with E3 (4) = 0. move on. In ST12, it is determined whether or not the starting point x (n) exists in the small area Ci5. If there is, the process proceeds to ST14 with E3 (5) = 1, and if not, the process proceeds to ST13 with E3 (5) = 0. move on. In ST13, it is determined whether or not the starting point x (n) exists in the small area Ci6.
(6) = 1 and the process proceeds to ST14.
The process proceeds to ST14 with (6) = 0.

In ST14, the starting point x (n) is set to the small area Cf
It is determined whether or not it exists in a and j. If it exists, the process proceeds to ST15 with E4 = 1, and if not, ST4 remains at E4 = 0
Proceed to 15.

In ST15, it is determined whether or not n <80. If n <80, since one sweep has not been completed yet, the process returns to ST4, where the value of n is incremented by 1, and the laser beam is again emitted. Thereafter, the processing up to ST15 is repeated, and n
= 80, one sweep is completed, and ST
It will advance to 16.

In ST16, x (n) (n = 1 to 80)
Based on the data, the object detection such as the number of objects, the direction, distance, size, moving direction, and moving speed of each object is determined. Further, from ST17 to ST34, the first to fourth types of detection abnormality are determined.

In ST17, it is determined whether E1 = 0. If E1 = 0, it means that the starting point x does not exist in the detection target area C in the current sweep, and it is then determined whether or not T1 ≧ 100 in ST18. This ST
If T1 ≧ 100 in 18, it means that no starting point x exists in the detection target area C over 100 or more sweeps (and thus 10s or more), and it is a type 1 detection abnormality. Is determined. If T1 is not 100 in ST18, it means that the time during which the starting point x does not exist is less than 10 s, and it is not determined that the first type is abnormal, and the process proceeds to ST19 while maintaining the value of T1. If E1 is not 0 in ST17, it means that the starting point x was present in the detection target area C in the current sweep, and T1 = 0 and E1 = 0, and ST19
Proceed to.

In ST19, it is determined whether E2 = 0. If E2 = 0, the small area C8j in the current sweep
That the starting point x does not exist within
At 20, it is determined whether or not T2 ≧ 3000. This ST2
If T2 ≧ 3000 at 0, small area C over 3000 sweeps (and thus 300 s or more)
This means that there is no starting point x in 8j, and it is determined that this is a second type detection abnormality. If T2 is not equal to or more than 3000 in ST20, it means that the time during which the starting point x does not exist is less than 300 s, and it is not determined that the second type is abnormal, and the process proceeds to ST21 while maintaining the value of T2. If E2 is not 0 in ST19,
This means that the starting point x was present in the small area C8j in this sweep, and T2 = 0, E2 = 0, and ST21
Proceed to.

In ST21, it is determined whether E3 (1) = 0. If E3 (1) = 0, it means that the starting point x does not exist in the small area Ci1 in the current sweep, and it is then determined in ST22 whether T3 (1) ≧ 600. If T3 (1) ≧ 600 in ST22, sweeping is performed 600 times or more (thus, 60s or more).
No starting point x was present in the small area Ci1 over this period, and it is determined that this is a third type detection abnormality. Unless T3 (1) ≧ 600 in ST22, it means that the time during which the starting point x does not exist is less than 60 s, it is not determined to be the third type of detection abnormality, and the process proceeds to ST23 while holding the value of T3 (1). And proceed. If E3 (1) is not equal to 0 in ST21, it means that the starting point x exists in the small area Ci1 in the current sweep, and T3
3 (1) = 0, E3 (1) = 0, and the process proceeds to ST23.

From ST23 to ST32, E3
Similar processing is performed for (j) and T3 (j) (j = 2 to 6), and the third processing for the small area Cij (j = 2 to 6) is performed.
The determination of the species detection abnormality is made in the same manner as the determination of the small area Ci1.

In ST33, it is determined whether E4 = 0. If E4 = 0, the small area Cf in the current sweep
This means that the starting point x does not exist in a and j, and then it is determined whether or not T4 ≧ 300 in ST34. This ST
If T4 ≧ 300 at 34, the small region Cfa, j is obtained over 300 or more sweeps (thus, 30s or more).
That there was no origin x in
It is determined that this is a fourth type of detection abnormality. If T4 is not equal to or greater than 300 in ST34, it means that the time during which the starting point x does not exist is less than 30 s, and it is not determined to be the fourth type of detection abnormality, and the process proceeds to ST35 while holding the value of T4.
If E4 is not equal to 0 in ST33, it means that the starting point x exists in the small area Cfa, j in the current sweep, and the process proceeds to ST35 with T4 = 0 and E4 = 0.

From ST35, returning to ST2, T1,
The values of T2, T3 (j) (j = 1 to 6) and T4 are each incremented by 1, and n = 0 in ST3, and the same processing is repeated for the next sweep.

FIG. 8 is a diagram for explaining a safe driving system for detecting a preceding vehicle by the above-described object detection device A and ensuring driving safety.

This safety driving system sweeps and emits a laser beam from the object detection device A mounted on the vehicle toward the front of the vehicle.
By receiving reflected laser light from the preceding vehicle, the preceding vehicle is detected and the inter-vehicle distance to the preceding vehicle is determined. The system is configured to issue an alarm or automatically apply a brake when the inter-vehicle distance is too short or when the inter-vehicle distance is suddenly reduced.

In addition to the preceding vehicle, vehicles traveling in the oncoming lane, roadside reflectors,
There are peripheral objects such as centerline reflectors, road signs, signboards, and other roadside installations. In FIG. 8, the object detection device A mounted on the own vehicle X0 detects a signboard X1, a roadside reflector X2, a preceding vehicle X3, and an oncoming vehicle X4. In addition, even if the preceding vehicle X3 or the oncoming vehicle X4 does not exist, since the own vehicle X0 having the object detection device A is moving, the vehicle X0 travels a certain time or more (that is, travels a certain distance or more). , Objects such as the signboard X1 and the roadside reflector X2 always enter the detection target area C. In other words, even if there is no preceding vehicle, some object is surely detected after a certain period of time (ie, a certain distance or more). Then, those objects enter from the long-distance region C8j (FIG. 6B), and both end regions Ci1 or Ci6 (FIG. 6B).
(C)).

The detection abnormality judging section 13 of the object detecting device A
The light receiving state of the reflected laser light from the small area Cij is monitored over time, and the occurrence of the above-described first, second, third, and fourth detection abnormalities is determined.

When it is determined that the first type of detection abnormality has occurred, the detection operation of the object is stopped to stop the function of the safe driving system, and that the detection abnormality has occurred to the driver and the safe driving is performed. It alerts that the function of the system has stopped and indicates that a first type of detection abnormality has occurred.

When it is determined that the second or third type of detection abnormality has occurred, the object detection operation and the function of the safe driving system are executed as they are, and the driver is notified that the detection abnormality has occurred. An alarm is issued and the type of detection abnormality is displayed.

When it is determined that the fourth type of detection abnormality has occurred, the detection operation of the object is executed as it is, and only the function of the safe driving system is temporarily stopped. And heavy rain
When the detection abnormal state due to the dense fog is resolved, the function of the safe driving system is restored. In this case, the driver is notified of the suspension and recovery of the function of the safe driving system.

FIG. 9 is a diagram for explaining a traffic monitoring system in which the above-described object detection device A is installed on a road and monitors traffic volume.

In this traffic monitoring system, a vehicle is detected by sweeping and projecting laser light from an object detecting device A installed on a road and receiving reflected laser light from the vehicle. Then, send the detection signal to the center,
It is designed to monitor traffic volume.

In FIG. 9, the object detection device A installed in the separation zone (shaded area) detects the roadside reflector X2 and the traveling vehicle X5. After a certain time,
Some traveling vehicles pass through the detection target area C of the object detection device A. These vehicles enter from the long-distance region C8j in FIG. 6 (b) and exit from both end regions Ci1 or Ci6 in FIG. 6 (c), or invade from both end regions Ci1 or Ci6 and enter from the long-distance region C8j. You will go out.

The detection abnormality judging section 13 of the object detection device A
The light receiving state of the reflected laser light from the small area Cij is monitored over time, and the occurrence of the above-described first, second, third, and fourth detection abnormalities is determined. When it is determined that the first type, second type, and third type detection abnormalities have occurred, the fact that these abnormalities have occurred and the type of the abnormalities are transmitted to the center.

The embodiments of the present invention have been described above.
The present invention is not limited to the embodiment described above. Depending on the application of the object detection device, for example, the processing and control after the detection of the object, such as displaying the distance to the detected object and its direction, or controlling when the object enters a predetermined area It is also possible to output a signal to cause the device to perform a predetermined operation. Also, the determination time in the determination of the detection abnormality may be freely set according to the use of the object detection device, or a function that can freely set the determination time may be provided.

As a medium for detecting an object, an ultrasonic wave may be used instead of a laser beam. In that case, an ultrasonic wave transmitting means is provided in place of the above-mentioned light projecting means, and an ultrasonic wave receiving means is provided in place of the light receiving means, and the ultrasonic wave transmitting means transmits ultrasonic waves to a predetermined area. In addition, the object may be detected by receiving the reflected wave from the object by the ultrasonic wave receiving means, and the receiving state of the receiving means may be monitored over time.
In addition, it is also possible to use infrared rays or radio waves.

The use of the object detection device according to the present invention is not limited to the use described in the above embodiment, but can be applied to the detection of the position of an airplane or a ship using a radio wave radar.

[0078]

As described above, the object detecting device of the present invention
Using the original function of receiving the reflected light of the object detection device and detecting the object, by monitoring the light receiving state of the reflected light with time, it is possible to determine a detection abnormal state where the object cannot be normally detected, It has a function called. Then, by monitoring the detection target area divided into a plurality of small areas, it is also possible to determine what cause the detection abnormality state.

Therefore, regarding the detection abnormality due to the dirt on the window, a separate light-emitting unit and a light-receiving unit are not required for detecting the dirt on the window. A separate light receiving unit is not required for object detection for monitoring the object. Therefore, in order to provide a light receiving unit for abnormality determination different from the light receiving unit for object detection,
There is no problem that the volume of the device increases, the cost increases, and the number of assembling processes increases. Further, there is also a problem that accurate detection abnormality cannot be determined because diffused reflected light or specular reflected light from the window is not properly received. Does not occur. Furthermore, regarding the undetectable state of the distant area due to heavy rain and dense fog,
Since a sensor for detecting dense fog is not required, there is no problem that the cost is increased and the apparatus is complicated.

That is, the object detecting apparatus of the present invention does not require a light receiving section for detecting an abnormal state other than the object detection in order to add a function of judging an abnormal state of detection. Cost increase, increase of assembly process, high precision required for assembly, complexity of equipment,
This problem is eliminated at once.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a basic configuration of the present invention.

FIG. 2 is a diagram illustrating a basic principle of object detection according to the present invention.

FIG. 3 is a diagram illustrating a basic principle of detection abnormality determination according to the present invention.

FIG. 4 is a diagram showing a configuration of an object detection device according to the present invention.

FIG. 5 is a diagram illustrating a detection target area of the object detection device.

FIG. 6 is a diagram illustrating a monitoring area of the object detection device.

FIG. 7 is a flowchart illustrating a flow of an object detection process and a detection abnormality determination process of the object detection device.

FIG. 8 is an explanatory diagram of a safe driving system using the object detection device.

FIG. 9 is an explanatory diagram of a traffic monitoring system using the object detection device.

FIG. 10 is a diagram showing a configuration of a conventional object detection.

[Explanation of symbols]

 Reference Signs List A object detection device C detection target area X detection target object 10 arithmetic control device 11 control unit 12 calculation unit 13 detection abnormality determination unit 20 light emitting device 30 light emitting device 40 light receiving device 50 case 60 translucent window 110 arithmetic control device 113 Abnormality diagnostic device 120 Light emitting device 130 Light emitting device 141 Object detecting light receiving device 142 Abnormal diagnostic light receiving device 150 Case 160 Window

Continuation of the front page (56) References JP-A-3-238383 (JP, A) JP-A-8-124237 (JP, A) JP-A 8-292260 (JP, A) JP-A-6-242239 (JP, A) , A) JP-A-5-119153 (JP, A) JP-B-3-30116 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01S ^7/ 48-7/64 G01S 17/00-17/95 G01S 15/00-15/96

Claims (9)

(57) [Claims] 1. An object detection device in which a light projecting unit projects light to a predetermined region and a light receiving unit detects an object by receiving reflected light from the object. It is divided into small areas, and the light receiving state of the reflected light from within the plurality of small areas is temporally monitored based on the output of the light receiving means, and a detection abnormality in which an object cannot be normally detected based on the light receiving states. An object detection device comprising: a detection abnormality determining unit that determines a state. 2. The detection abnormality judging means divides the area into a plurality of small areas with respect to a distance direction to an object, and temporally monitors a light receiving state of reflected light from the plurality of small areas. The object detection device according to claim 1, wherein: 3. The object detecting apparatus according to claim 2, wherein the plurality of small areas are divided into a long distance area and other areas. 4. The object detecting apparatus according to claim 2, wherein the plurality of small areas are divided into an area at a medium distance or more and a short distance area. 5. The detection abnormality judging means divides the area into a plurality of small areas with respect to a projection angle direction, and temporally monitors a light receiving state of reflected light from the plurality of small areas. 2. The object detection device according to claim 1, wherein: 6. The detection abnormality judging means divides the area into a plurality of small areas with respect to a distance direction to an object and a projection angle direction, and detects a light receiving state of reflected light from the plurality of small areas. The object detection device according to claim 1, wherein the object is monitored temporally. 7. The detection abnormality judging means further judges a type of a detection abnormality based on a light receiving state of reflected light from the plurality of small areas monitored over time. The object detection device according to claim 1, wherein: 8. The object detection apparatus according to claim 1, wherein the light is swept and projected to determine a distance and a direction to the object. 9. An object detection apparatus of a type in which an ultrasonic wave transmitting means transmits an ultrasonic wave to a predetermined region and an ultrasonic wave receiving means detects an object by receiving a reflected wave from the object. Dividing the predetermined area into a plurality of small areas;
The reflected waves from within the plurality of small areas based on the output of
Monitor the reception status of the
And an abnormality detection means for judging an abnormal state of detection.