JPH11183623A - Radar apparatus and radar measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radar apparatus which realizes a high-speed processing operation, whose measuring reliability is high and whose production cost is low, and to provide a radar measuring method. SOLUTION: A radar apparatus is featured in such a way that irradiation laser light Li is shone at obstacles 102a to 102c, that beams of reflected laser light Lr reflected by the obstacles 102a to 102c are received so as to generate distance data D, that only specific data is extracted among a plurality of continued data D among from the distance data D and that the extracted specific data is cluster-processed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar apparatus, and more particularly to a radar apparatus and method for obtaining a large amount of data by scanning to recognize the presence of an obstacle, such as a laser radar apparatus for a vehicle.

[0002]

2. Description of the Related Art Conventionally, a laser radar apparatus for a vehicle has been developed and widely used for various purposes such as measurement of an inter-vehicle distance, detection of an obstacle ahead, prevention of a rear-end collision of a vehicle, and the like.

[0003] In this laser radar device for a vehicle, the laser beam is repeatedly irradiated with the irradiation angle being changed little by little within a predetermined irradiation angle range centered on the front direction of the vehicle. Later, the time until it is reflected by the obstacle and returns is collected as data, and the presence, type, position, distance, etc. of the obstacle are recognized based on this data.

Next, a conventional radar apparatus will be described with reference to the drawings.

FIG. 5 is a block diagram of a conventional radar device. The light transmitting unit 1 emits the irradiation laser light Li while repeatedly scanning in one direction within an irradiation range of an irradiation angle θ = −10 ° to + 10 ° centering on the front of the vehicle. The light receiving unit 3 receives the reflected laser light Lr reflected by the obstacles 2a to 2c. The distance measuring section 4 measures the time from the output of the light emission signal Si of the light transmitting section 1 to the output of the light receiving signal Sr of the light receiving section 3 and calculates the distance data D based on the measured time. The data storage unit 6 sequentially stores the calculated distance data D in association with the irradiation angle θ. The clustering unit 7 reads a group of distance data D from the data storage unit 6 and clusters a series of distance data D for each reflector such as a reflector, which is a component of the vehicle that is the obstacles 2a to 2c. Is performed, and the distance data Da to Dc, which are the characteristic values of each cluster, are converted to the irradiation angle θa.
と 共 に θc and the like. The vehicle recognition unit 8 calculates distance data Da to Dc, which are characteristic values of each cluster, and irradiation angles θa to
The existence, type, position, and distance of the obstacles 2a to 2c are recognized from data such as θc. The display unit 9 displays the existence, type, position, and distance of the obstacles 2a to 2c recognized by the vehicle recognition unit 8. The control unit 10 includes a light transmitting unit 1, a light receiving unit 3 to a display unit 9
Integrated control of each part.

FIG. 6 is a processing flowchart of a conventional radar measuring method.

First, the control unit 10 substitutes n = 1 into an internal register (not shown) (step S1).

When the control section 10 outputs a scanning start signal Ssc to the distance measuring section 4, the light transmitting section 1 generates and outputs an irradiation signal Si and irradiates the irradiation laser light Li at a predetermined irradiation angle θ (n). . When the irradiation laser light Li reaches the obstacle 2a and is reflected and the reflected laser light Lr is received by the light receiving unit 3, the light receiving unit 3 generates and outputs a light receiving signal Sr. The distance measuring unit 4 measures the time from generation of the irradiation signal Si to output of the light reception signal Sr, that is, the round trip time t (n) (n: an integer), and the distance data D (n) = c, which is a calculation formula. * (T
(N)) / 2 to calculate distance data D (n) (c: light speed constant) (step S2).

The control unit 10 determines whether or not the light receiving unit 3 has received the reflected laser light Lr before the light transmitting unit 1 irradiates the next irradiation laser Li at the irradiation angle θ (n + 1) (step S3). .

The reflected laser beam Lr cannot be received, ie, D
When (n) = ∞, it is determined that the obstacle 2a does not exist at the irradiation angle θ (n), and the distance data D (n) = “0” is stored in the n-th address of the data storage unit 6. and n (step S4).

If the reflected laser beam Lr can be received, that is, if D (n) ≠ ∞, the distance data D (n) of the obstacle 2a is stored in the n-th address of the data storage unit 6 together with the value n. (Step S5).

Subsequently, the control unit 10 controls the irradiation laser light L
The value n is increased while changing the irradiation angle θ (n) of i, and the data storage unit 6 is similarly set for the obstacles 2b and 2c.
The distance data D is sequentially stored together with the value n (step S
6, S7, S2 to S6). In this manner, all distance data D (n) corresponding to the value n are sequentially stored in the data storage unit 6.

When one scan of the irradiation laser beam Li is completed (step S6), the control unit 10 sets the plurality of distance data D (1) to D (n) stored in the data storage unit 6 and the corresponding values. 1 to n are transferred to the clustering unit 7. The clustering unit 7 performs a cluster process on the basis of the obstacles 2a to 2c, such as reflectors that constitute a vehicle or the like (step S). This cluster processing is performed using distance data D
Are grouped for each reflection object and collected as a cluster.

The vehicle recognizing section 8 compares the distance data D (n) obtained by the cluster processing and characteristic values such as the irradiation angle θ (n) corresponding to the value n with a predetermined pattern stored in advance. And types of obstacles 2a to 2c such as vehicles
The position and distance are recognized (step S9) and displayed on the display unit 9.

Next, an example of a vehicle recognition process will be described with reference to FIGS.

FIG. 7A is a conceptual diagram of the positional relationship between obstacles in the conventional radar apparatus, FIG. 7B is a conceptual diagram of the distance data measurement result, and FIG. 8A is a conceptual diagram of the cluster processing result. FIG. 8B is a conceptual diagram of a vehicle recognition result.

As shown in FIG. 7A, obstacles 2a to 2
Assume that c is at a given location.

As shown in FIG. 7B, the irradiation laser light L
The distance data D indicated by a circle obtained by the scanning of i is sequentially stored. Here, the reason why the distance data D indicated by the circle represents an arc is that the irradiation laser beam Li emitted from the laser diode of the light transmitting unit 1 has an irradiation pattern that spreads away from the light transmitting unit 1, and thus the comparison is made. Obstacle 2a located far away
2c, the irradiation laser light Li is applied to a relatively large area of the surface of the obstacles 2a to 2c, and the reflected laser light Lr is weaker at both ends than at the center of the obstacles 2a to 2c. This is because some characteristics are measured farther.

As shown in FIG. 8A, by clustering, the distance data D indicated by a circle is summarized for each of the obstacles 2a to 2c or for each component of the obstacles 2a to 2c.
~ Cluster C

As shown in FIG. 8B, the obstacles 2a are removed from each of the clusters A to C by the vehicle recognition processing.
The presence, type, and position (irradiation angle) θa to θc and distances Da to Dc of.

As described above, in the conventional radar apparatus, all distance data D (1) to D (1) to D
(N) is stored as it is, and all these distance data D
Cluster processing and vehicle recognition processing are performed using (1) to D (n).

Further, in the conventional radar apparatus,
When trying to extend the measurement range to a long distance, the irradiation laser light Li does not reach the obstacles 2a to 2c, or the intensity of the reflected laser light Lr is low, so that a sufficient number of distance data D cannot be obtained. In such a case, since the cluster processing or the vehicle recognition processing cannot be performed, the reliability of the radar apparatus is impaired. Therefore, in order to solve this problem, a sufficient number of distance data D is obtained by making the irradiation angle θ of the irradiation laser beam Li finer and increasing the number of irradiations of the irradiation laser beam Li to obtain the radar device. Reliable.

[0023]

However, the conventional radar apparatus has the following problems.

First, if the step of the irradiation angle θ of the irradiation laser beam Li is made smaller, the number of distance data D increases, so that the clustering in the clustering unit 7 and the obstacles 2a to 2 in the vehicle recognition unit 8 are performed. There is a problem that the recognition process of 2c takes time.

Second, if the step of the irradiation angle θ of the irradiation laser beam Li is made smaller, the number of distance data D is increased, so that the storage capacity of the data storage unit 6 is increased and the production cost is increased. there were.

Here, the present invention provides a radar apparatus and a radar measurement method that realize high-speed processing, have high measurement reliability, and have low manufacturing costs.

[0027]

In order to solve the above problems,
The present invention employs the following novel features and means.

That is, the feature of the apparatus of the present invention is that an irradiating means (101) for irradiating a laser beam (Li in FIG. 1) to an obstacle (102a to 102c) and an obstacle (102a to 102c).
c) receiving the laser beam (Lr) reflected by c) and generating distance data (D); and receiving only specific data from continuous data (D) of the distance data (D). The radar apparatus includes a data compression unit (105) for extracting data and a clustering unit (107) for performing cluster processing on the extracted specific data.

A feature of the method of the present invention is that a laser beam (L in FIG. 1) is used.
i) is irradiated on the obstacles (102a to 102c), and the laser light (Lr) reflected by the obstacles (102a to 102c)
Is received to generate distance data (D), a specific data is extracted from a plurality of continuous data (D) among the distance data (D), and the extracted specific data is subjected to a cluster processing method. is there.

By employing such a method and means, in the present invention, only the distance data having high measurement reliability is extracted, and the cluster processing and the vehicle recognition processing are performed.

[0031]

Embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a radar apparatus according to an embodiment of the present invention. The light transmitting unit 101 includes an irradiation laser beam Li
Is an irradiation angle θ = −10 ° to +10 centered on the front of the vehicle.
Irradiation is performed while repeatedly scanning in one direction within the irradiation range of °. The light receiving unit 103 receives the reflected laser light Lr reflected by the obstacles 102a to 102c. Distance measuring unit 104
Is obtained from the light emission signal Si output of the light transmission unit 101
The time until the light receiving signal Sr is output is measured, and the distance data D is calculated based on the measured time. The data compression unit 105 is configured to output two consecutive distance data D (2n) and D from the n distance data D obtained during one scan calculated by the distance measurement unit 104.
(2n + 1) are sequentially taken out and their values are compared with each other to extract only distance data D having a smaller value, that is, closer to the own vehicle. The data storage unit 106 sequentially stores the calculated distance data D in association with the irradiation angle θ. The clustering unit 107 reads the group of distance data D from the data storage unit 106, and stores a series of the group of distance data D
Cluster processing is performed for each reflector, such as a reflector, which is a component of a vehicle or the like, which is 102c, and the distance data Da to Dc, which are the characteristic values of each cluster, are converted to the irradiation angles θa to
Output together with θc and the like. The vehicle recognition unit 108 calculates the distance data Da to Dc, which are the characteristic values of each cluster, and the irradiation angle θa.
The presence, type, position, and distance of the obstacles 102a to 102c are recognized from the data such as? C. The display unit 109 displays the existence, type, position, and distance of the obstacles 102a to 102c recognized by the vehicle recognition unit 108. The control unit 110
The light transmitting unit 101 and the light receiving unit 103 to the display unit 109 are integrally controlled.

The reason that the data compression unit 105 compares the continuous distance data D (2n) and D (2n + 1) is that the continuous distance data D (2n) and D (2n + 1) are obtained by the same obstacle 102a. This is because it is highly possible that

There are two reasons for extracting only the closer distance data D. First, the irradiation laser beam Li emitted from the laser diode of the light transmitting unit 101 has an irradiation pattern that spreads as the distance from the light transmitting unit 101 increases, so that the obstacles 102a to 102c that are relatively far away are obstacles. Irradiation laser light Li is applied to a relatively large area of the surfaces 102a to 102c, and the intensity of the reflected laser light Lr is lower at both ends than at the center of the obstacles 102a to 102c. This is because the closer distance data D has higher reliability. Second, the distance data D of the obstacles 102a to 102c closer to the host vehicle is more important for prompt collision warning and brake control to avoid the obstacles 102a to 102c.

Next, a radar measurement method according to the present embodiment will be described with reference to the drawings.

FIG. 2 is a flowchart of the radar measuring method according to the embodiment of the present invention.

First, the control unit 110 substitutes n = 1 into an internal register (not shown) (step S10).
1).

When the control unit 110 sends the scanning start signal Ssc to the distance measuring unit 104, the distance measuring unit
i to the light transmitting unit 101, and the light transmitting unit 101 irradiates the irradiation laser light Li at the irradiation angle θ (2n). When the irradiation laser light Li reaches the obstacle 102a and is reflected and the reflected laser light Lr is received by the light receiving unit 103, the light receiving unit 103 generates and outputs a light receiving signal Sr. The distance measuring unit 104 measures the time from generation of the irradiation signal Si to output of the light reception signal Sr, that is, a round trip time t (2n) (n: an integer), and D is a formula for calculating the distance data D (2n). (2n) = c *
Distance data D from (t (2n)) / 2 to (c: light speed constant)
(2n) is calculated (step S102).

Next, the light transmitting unit 101 irradiates the irradiation laser beam Li at the irradiation angle θ (2n + 1), and similarly, the distance measuring unit 1
04 calculates distance data D (2n + 1) (step S103).

The control section 110 determines whether or not the distance data D (2n) = ∞ calculated from the formula for calculating the distance data D (step S104). In this step, the light emitting unit 10
1 until the next irradiation laser beam Li is irradiated.
Is unable to receive the reflected laser beam Lr,
This is provided to determine that 2a does not exist.

In step S104, the distance data D (2
If n) = ∞, control unit 110 next determines whether or not distance data D (2n + 1) = ∞ (step S10).
5). If the distance data D (2n + 1) = {, the distance data D (2n + 1) = "0" is stored in the data storage unit 106 together with the value (2n + 1) (step S106). If the distance data D (2n + 1)}, Distance data D (2n +
1) is stored in the data storage unit 106 together with the value (2n + 1) (step S107).

In step S104, the distance data D
If (2n) ２, the control unit 110 next determines whether or not the distance data D (2n + 1) = ∞ (step S1).
08). If the distance data D (2n + 1) = ∞, the distance data D (2n) is stored in the data storage unit 106 together with the value 2n (step S109). Distance data D (2n +
1) If ≠ ∞, the data compression unit 105 sets the distance data D
(2n) and D (2n + 1) are compared (step S11).
0) The result is transferred to the control unit 110, and the control unit 110 transmits the smaller distance data D (2n) or D
(2n + 1) is stored in the data storage unit 106 as the value 2n or 2n +
1 and distance data D (2n) having a larger value.
Alternatively, D (2n + 1) is deleted (step S107 or S109).

The control unit 110 and the data compression unit 105
Subsequently, the value n is increased, and the irradiation laser beam Li is similarly irradiated at the irradiation angle θ (n), and the obstacles 102b, 1
02c, the comparison, storage, and deletion of the distance data D are sequentially performed in the same manner, and compression is repeated to reduce the number of distance data D by 1 /.
2 and sequentially stored in the data storage unit 106 (steps S110, S111, S102 to S110).

Of the adjacent distance data D thus measured, only the smaller distance data D is sequentially stored in the data storage unit 106 together with the corresponding value n.

When one scan of the irradiation laser beam Li is completed (step S 110), the control unit 110 reads a series of compressed distance data D stored in the data storage unit 106 and sends it to the clustering unit 107. The clustering unit 107 performs a cluster process for each of the obstacles 102a to 102c, such as a reflector that constitutes a vehicle or the like (step S112). This cluster process is a process of grouping the distance data D for each reflection object and putting them together as a cluster.

As an example, a set of continuous distance data D is extracted, and the minimum distance data D in the set of distance data D and the obtained value n of the distance data D are extracted as feature values. Here, when the difference between the adjacent distance data D is large, it is assumed that the distance data D is reflected by the different obstacles 102a to 102c and is collected as another cluster.

The vehicle recognizing unit 108 compares the distance data D (n) obtained by the cluster processing and characteristic values such as the irradiation angle θ (n) corresponding to the value n with a predetermined pattern stored in advance. To recognize the existence, type, position, and distance of obstacles 102a to 102c such as vehicles (step S11).
3) Display on the display unit 109.

Next, an example of a vehicle recognition process will be described with reference to FIGS.

FIG. 3A is a conceptual diagram of the positional relationship between obstacles of the radar apparatus according to the present embodiment, FIG. 3B is a conceptual diagram of distance data measurement results and compression processing results, and FIG. FIG. 4B is a conceptual diagram of a cluster processing result, and FIG. 4B is a conceptual diagram of a vehicle recognition result.

As shown in FIG. 3A, the obstacle 102a
Suppose that ~ 102c are located.

As shown in FIG. 3B, from the distance data D of the circles and crosses obtained by scanning with the laser beam, only the distance data D of the circle with high reliability is extracted by data compression processing. , Are sequentially stored together with the obtained value n of the distance data D (n).

As shown in FIG. 4 (a), when the distance data D indicated by a circle is clustered as indicated by solid lines in the figure, clusters A to C are obtained.

As shown in FIG. 4B, the minimum value, average value, median value, etc. of the distance data D (n) of each of the clusters A to C, the irradiation angle θ (n) corresponding to the value n, etc. Of the obstacles 102a to 102c, the types, positions (irradiation angles) θa to θc, and the distances Da to Dc
Recognize.

As described above, the radar apparatus according to the present embodiment effectively utilizes the characteristics of the radar apparatus and the data obtained from the radar apparatus to obtain highly reliable data from the distance data D group obtained by measurement. After extracting and storing only the data, cluster processing and vehicle recognition processing are performed.

In this embodiment, laser light is used as a medium for distance measurement, but infrared light, visible light, ultrasonic waves, electromagnetic waves, or the like may be used.

In this embodiment, the value n and the distance data D (n) are stored in the data storage unit 106 in association with each other, but the irradiation angle θ (n) and the distance data D (n) are associated with each other. Alternatively, the data may be stored in the data storage unit 106.

In the present embodiment, the case where two consecutive distance data D are compressed into one distance data D, that is, the case where the compression ratio is 1/2 has been exemplified, but the number of consecutive distance data D is limited. There is no. If the number of continuous distance data D is increased, the compression ratio can be further improved.

In the present embodiment, as the compression method, only the minimum distance data D among a plurality of continuous distance data D is stored, and other distance data D are deleted. Instead of the minimum value of D, an average value or distance data D at the center position among the plurality of distance data D may be stored. In addition, specific data may be selected from a plurality of distance data by using an arbitrary method.

[0059]

By adopting the above configuration, the radar apparatus and the radar measuring method of the present invention exhibit the following effects.

First, since the total number of distance data is reduced and the calculation processing time is shortened, there is an advantage that the speed of recognizing obstacles can be improved.

Second, since the number of distance data used for the clustering process and the vehicle recognition process does not increase, there is an advantage that the storage capacity does not increase and the manufacturing cost is low.

Third, since the arithmetic processing is performed using only highly reliable distance data extracted from a large number of distance data, there is an advantage that measurement accuracy is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of a radar device according to an embodiment of the present invention.

FIG. 2 is a flowchart of a radar measurement method according to the embodiment of the present invention.

FIG. 3A is a conceptual diagram of a positional relationship between obstacles of the radar apparatus of the present invention, and FIG. 3B is a conceptual diagram of a result of distance data measurement and a result of compression processing.

FIG. 4A is a conceptual diagram of a cluster processing result, and FIG. 4B is a conceptual diagram of a vehicle recognition result.

FIG. 5 is a block diagram of a conventional radar device.

FIG. 6 is a processing flowchart of a conventional radar measurement method.

7A is a conceptual diagram of a positional relationship between obstacles in a conventional radar apparatus, and FIG. 7B is a conceptual diagram of a result of distance data measurement.

FIG. 8A is a conceptual diagram of a cluster processing result, and FIG. 8B is a conceptual diagram of a vehicle recognition result.

[Explanation of symbols]

 1,101 Light transmitting unit 2a-2c, 102a-102c Obstacle 3,103 Light receiving unit 4,104 Distance measuring unit 105 Data compressing unit 6,106 Data storing unit 7,107 Clustering unit 8,108 Vehicle recognizing unit 9,109 Display unit 10, 110 Control unit

Claims (14)

[Claims] 1. An irradiating means for irradiating irradiation light at different irradiation angles, a light receiving means for receiving the irradiation light reflected by an obstacle and generating distance data to the obstacle, A radar apparatus comprising: a data compression unit that extracts specific data from the distance data; and a clustering unit that performs a cluster process to combine the specific data. 2. Irradiation means for irradiating irradiation light at different irradiation angles, light receiving means for receiving the irradiation light reflected by an obstacle and generating distance data to the obstacle, A data compression unit for extracting specific data from the distance data, a clustering unit for performing a cluster process for collecting the specific data, and a recognition unit for recognizing the obstacle from a cluster processing result of the clustering unit. A radar device characterized by the above-mentioned. 3. The radar apparatus according to claim 1, wherein said data compression means sets the minimum distance data among the plurality of continuous distance data as the specific data. 4. The radar apparatus according to claim 1, wherein the data compression means sets the distance data having an average value among the plurality of continuous distance data as the specific data. 5. The data compression unit according to claim 1, wherein the specific data is set to zero when the irradiation light reflected by the obstacle is not detected.
5. The radar device according to 3 or 4. 6. The method according to claim 1, wherein the clustering unit combines the specific data adjacent to each other as separate clusters when the difference is large.
The radar device according to 3, 4, or 5. 7. The vehicle recognizing means, when the specific data is zero, determines that there is no obstacle at the irradiation angle at which the specific data which is zero is obtained. 7. The radar apparatus according to claim 2, 3, 4, 5, or 6. 8. Irradiating the irradiation light with changing the irradiation angle, receiving the irradiation light reflected by the obstacle, generating distance data to the obstacle, and calculating the distance data from the plurality of continuous distance data. A radar measurement method comprising: extracting specific data; and performing a cluster process for collecting the specific data. 9. Irradiating irradiation light at different irradiation angles, receiving the irradiation light reflected by the obstacle, generating distance data with respect to the obstacle, and generating a plurality of distance data from the plurality of continuous distance data. A radar measurement method comprising: extracting specific data; performing a cluster process for collecting the specific data; and recognizing the obstacle based on a result of the cluster process. 10. The radar measurement method according to claim 8, wherein the specific data is a minimum value among a plurality of the continuous distance data. 11. The radar measurement method according to claim 8, wherein the specific data is an average value of a plurality of continuous distance data. 12. The radar measurement method according to claim 8, wherein the specific data is set to zero when the irradiation light reflected by the obstacle is not detected. . 13. The cluster processing according to claim 8, wherein when the difference between the specific data adjacent to each other is large, the cluster processing is combined into separate clusters.
The radar measurement method according to 0, 11 or 12. 14. The obstacle recognition process includes, when the specific data is zero, determining that there is no obstacle at the irradiation angle at which the specific data that is zero is obtained. 14. The radar measurement method according to claim 9, 10, 11, 12, or 13.