JP7449443B2 - Radar system and object detection method - Google Patents

Description

The present invention relates to a radar system that uses a radar device to detect objects existing in a monitoring target area.

As a radar device using microwave or millimeter wave bands, there is an FMCW (Frequency Modulated Continuous-Wave) radar device having a structure as shown in FIG.
Radar device 100 in FIG. 1 amplifies a frequency-modulated radar signal from FMCW transmission source 101 with transmission power amplifier 103 and emits it from transmission antenna 104. When an object T (reflecting object) exists within the detection range of the radar device 100, the radar transmission wave is reflected by the object T. The reflected wave from the object T is received by the reception antenna 105 of the radar device 100, amplified by the reception power amplifier 106, and then mixed with the transmission radar signal component from the power divider 102 by the mixer 107 to form an IF signal. converted. The IF signal output from the mixer 107 is subjected to A/D conversion and signal processing in the signal processing section 108. As a result, radar information such as the received power reflected by the object T (reflected wave power), the distance to the object T, the direction of the object T, and the speed when the object T is moving (relative speed with respect to the radar device 100) is obtained. Detection results are obtained.

Various inventions have been proposed so far regarding such radar devices.
For example, Patent Document 1 discloses that a millimeter wave radar is installed on a moving object, and the distance between a first reflector and a second reflector each installed near a target position and the distance from these reflectors are determined. An invention is disclosed in which the distance to a target position is measured based on the reception result of reflected waves.

International Publication 2018/235397

Radar devices are used to detect objects present on the surface of roads, runways, and other areas to be monitored. There are usually no reflective objects such as fallen objects or abandoned objects on roads or runways. Therefore, a radar device continues to send radar transmission waves to a detection range where there are no reflecting objects, and receives a received wave (reflected wave) only when some reflecting object appears within the detection range, and that object is detected. be done.

If an object detected by a radar device needs to be removed or recovered, having information about the object's shape will make it easier to search for the object. At this time, for example, a camera device is used in combination with a radar device. That is, when the presence of an object is recognized by the reflected wave power from the object by the radar device, the angle of view and focus of the camera device are adjusted to the location where the object exists, and a photograph is taken. As a result, a captured image of the object to be removed can be obtained, making it easier to recognize the detailed shape of the object.

When searching for and removing a detected object, a worker can use information on the object's location obtained from the radar device and information on the object's shape obtained from the camera device. However, depending on the angle of view taken by the camera device, only shape information of the object viewed from one direction can be obtained, making it difficult to faithfully capture the actual shape. As a result, a difference occurs between the object shape information obtained from the camera device and the actual object shape, causing confusion when searching for the object.

The present invention has been made in view of the above-mentioned conventional circumstances, and an object of the present invention is to provide a radar system that can more accurately capture the shape of an object detected by a radar device.

In the present invention, in order to achieve the above object, a radar system is configured as follows.
That is, the radar system according to the present invention is a radar system that uses a radar device to detect objects existing in a monitoring target area, and is installed at different positions, and the shape of the object detected by the radar device as seen from the own position. The present invention is characterized by comprising a plurality of object shape acquisition devices that acquire information, and a display device that displays an object shape image based on the plurality of shape information acquired by the plurality of object shape acquisition devices.

Here, the plurality of object shape acquisition devices may include a camera device. Further, the plurality of object shape acquisition devices may include a radar device. Note that the plurality of object shape acquisition devices may be composed of only a plurality of camera devices, may be composed of only a plurality of radar devices, or may be composed of a combination of one or more camera devices and one or more radar devices. It's okay.

Further, the radar system according to the present invention further includes a first radar control device that controls the operation of the first radar device, a second radar control device that controls the operation of the second radar device, and a first radar control device that controls the operation of the second radar device. The first radar control device includes a synchronization processing device that transmits a synchronization signal to the radar control device and the second radar control device, and the first radar control device controls the first radar device at a timing according to the synchronization signal received from the synchronization processing device. The second radar control device may control the operation of the second radar device at a timing according to a synchronization signal received from the synchronization processing device.

Moreover, instead of the synchronization processing device, each of the first radar control device and the second radar control device has a GNSS receiver that outputs time information obtained from a GNSS satellite, and the first radar control device , the operation of the first radar device is controlled at a timing according to the time information output from the GNSS receiver, and the second radar control device controls the operation of the second radar device at a timing according to the time information output from the GNSS receiver. The operation of the radar device may be controlled.

According to the present invention, it is possible to provide a radar system that can more accurately capture the shape of an object detected by a radar device.

It is a diagram showing an example of the configuration of a radar device. 1 is a diagram showing an overview of a radar system according to an embodiment of the present invention. FIG. 3 is a diagram showing how an object shape is specified using one sensor device. 4 is a diagram showing an example of a case where a detected object is photographed by the camera device 120 of FIG. 3. FIG. It is a figure showing an example of installation of a plurality of sensor devices. FIG. 3 is a diagram showing how an object shape is specified using a plurality of sensor devices. 7 is a diagram showing an example of a case where a detected object is photographed with the camera device 120A of FIG. 6. FIG. 7 is a diagram showing an example of a case where a detected object is photographed with the camera device 120B of FIG. 6. FIG. 7 is a diagram showing an example of a case where a detected object is photographed by the camera device 120C of FIG. 6. FIG. 7 is a diagram showing an example of a case where a detected object is photographed with the camera device 120D of FIG. 6. FIG. FIG. 3 is a diagram illustrating an example of a processing flow when an object is detected by a radar system according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of a coordinate system and detected objects of a radar device rotating in a horizontal direction. It is a figure showing the 1st example of composition which synchronizes a plurality of radar control devices. It is a figure showing the 2nd example of composition which synchronizes a plurality of radar control devices.

A radar system according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 2 shows an overview of a radar system according to an embodiment of the present invention. The radar system of this example includes a sensor device 200 including a radar device 100 and a camera device 120 installed toward a predetermined detection range R, and a radar control device 300 and a display device 400 installed in a control room, monitoring room, etc. It is equipped with Although only one sensor device 200 is shown in FIG. 2 to simplify the explanation, in reality, as shown in FIG. 5, a plurality of sensor devices 200 are arranged, each monitoring a different detection range R. be done.

The radar device 100 receives the reflected wave of the radar transmission wave transmitted to the detection range R, processes the signal, and outputs the obtained radar detection result to the radar control device 300. The radar monitoring device 300 causes the display device 400 to display detection information of an object X (a fallen object or an abandoned object) existing within the detection range R based on the radar detection result output from the radar device 100.

The detection range R of the radar device 100 is a predetermined section on a road surface such as a road or a runway, which is an area to be monitored, and the antenna angle of the radar device 100 is set to include the detection range R. The distance from the radar device 100 to the object X can be calculated by signal processing the reflected waves from the object X. Further, when the antenna of the radar device 100 is mechanically rotated, the angle (azimuth) of the object X with respect to the radar device 100 can be specified based on the rotation angle information of the antenna. Alternatively, if the angle of the beam of the radar transmission wave emitted from the antenna of the radar device 100 is electronically scanned, the angle (azimuth) of the object X with respect to the radar device 100 can be specified based on the beam scanning angle information. can do.

The distance and angle information obtained by the radar device 100 is transmitted to the camera device 120 via the radar control device 300. The camera device 120 rotates according to the angle information obtained by the radar device 100, adjusts the focus according to the distance information obtained by the radar device 100, and photographs the object X existing within the angle of view. Here, as shown in FIG. 3, when there is only one set of radar device 100 and camera device 120 (that is, when there is only one sensor device 200), object X can only be photographed from one direction. The problem in this case will be explained below.

FIG. 4 shows an example in which the object X is photographed in the arrangement shown in FIG. The upper part of Fig. 4 shows the shape of the actual object X viewed from above (that is, the object shape viewed from above), and the lower part of Fig. 4 shows the object shape obtained by photographing the object X from the direction of the arrow. The resulting object shape is shown. As described above, a difference may occur between the object shape identified from the photographed image and the actual object shape due to factors such as the angle of view of the camera device 120, the distance to the object X, and the illumination condition at the time of photographing. There is.

For example, even if the actual shape of an object has a certain area as shown in the upper part of Figure 4, if only a side view image is obtained, it will be recognized as a rod-shaped object as shown in the lower part of Figure 4. There is a possibility that it will happen. In this case, the object shape information transmitted to the worker (object searcher) is a "stick-shaped object," and the worker searches for the "stick-shaped object" at the site. As a result, due to the difference from the actual shape of the object, it takes more time than necessary to search for the object to be recovered. Furthermore, if the shape of the collected object differs from the shape of the prior information, it may lead to a lack of confidence in the collection result.

Therefore, in the radar system of this example, a plurality of sensor devices 200 including the radar device 100 and the camera device 120 are used in order to reduce the difference between the object shape identified from the captured image and the actual object shape. . FIG. 5 shows an example of installation of a plurality of sensor devices 200. In FIG. 5, a plurality of sensor devices 200 are installed on both sides of the road surface to be monitored, parallel to the road surface. Each sensor device 200 is equipped with a radar device 100 and a camera device 120. These plurality of sensor devices 200 are connected to a radar control device 300 installed in a control room, a monitoring room, etc. by an optical fiber cable or the like. That is, the radar control device 300 controls all the sensor devices 200 and manages information obtained from these sensor devices 200.

Here, it is assumed that one object exists on the road surface to be monitored, and the situation at that time is shown in FIG. 6 as viewed from above. In the example of FIG. 6, four sensor devices 200A, 200B, 200C, and 200D are installed around object X. The sensor device 200A includes a radar device 100A and a camera device 120A, and the same applies to the sensor devices 200B, 200C, and 200D.

First, it is assumed that the radar device 100A detects the reflected power from the object X and recognizes the existence of the object X. The radar device 100A can obtain the distance and angle to the object X with respect to its installation origin. Thereby, the camera device 120A, whose installation origin is the same as the radar device 100A, performs photography by adjusting the angle of view and focus to the location where the object X exists, based on the distance and angle information acquired by the radar device 100A.

FIG. 7 shows an example in which the object X is photographed with the camera device 120A of FIG. 6. The upper part of FIG. 7 shows the shape of the actual object X viewed from above, and the lower part of FIG. 7 shows the object shape obtained by photographing the object It is shown.

In the radar system of this example, the radar control device 300 controls all the sensor devices 200 and manages the information obtained from these sensor devices 200, so the position information of the object X detected by the radar device 100A is It can be shared as a whole system. Therefore, other sensor devices 200B, 200C, and 200D near the object It is possible to adjust the viewing angle and focus of 120D to match the location of object X.

FIG. 8 shows an example in which the object X is photographed with the camera device 120B of FIG. 6. The upper part of FIG. 8 shows the shape of the actual object X viewed from above, and the lower part of FIG. 8 shows the object shape obtained by photographing the object It is shown.

FIG. 9 shows an example in which the object X is photographed by the camera device 120C of FIG. 6. The upper part of FIG. 9 shows the shape of the actual object X viewed from above, and the lower part of FIG. 9 shows the object shape obtained by photographing the object It is shown.

FIG. 10 shows an example in which the object X is photographed by the camera device 120D of FIG. 6. The upper part of FIG. 10 shows the shape of the actual object X viewed from above, and the lower part of FIG. 10 shows the object shape obtained by photographing the object X from the direction of the arrow by the camera device 120D. It is shown.

In this way, by photographing the object X with a camera from a plurality of directions (four directions in this example), four images of different aspects can be obtained. The radar control device 300 performs image processing using a plurality of images of the object X, and generates an object shape image representing the shape of the object X. Various known techniques can be used to generate the object shape image, and for example, the technique described in Japanese Patent Application No. 4-151821 (Japanese Patent Application Laid-Open No. 5-342368) may be used. In addition, in this example, since the position of the camera device is fixed, in order to generate an object shape image, the angle at which the partial images of object You can also glue them together.

This makes it possible to generate an object shape image that is closer to the actual shape than an image taken with a single camera device. In this example, four sensor devices 200 are used to generate the object shape image, but the number of sensor devices 200 is not limited to this, and any number of sensor devices 200 of two or more may be used. Is possible. By using images of the object X taken from more directions, it becomes possible to generate an object shape image that is closer to the actual shape.

FIG. 11 shows an example of a processing flow when an object is detected by the radar system of this example. It is assumed that the radar control device 300 stores in advance the position information of the sensor device 200 in the system (that is, the position information of the radar device 100 and the camera device 120). The plurality of radar devices 100 monitor a road surface, which is a monitoring target area, under the control of the radar control device 300. When an object on the road surface is detected by one of the radar devices 100 (step S101), the radar detection result is transmitted from the radar device 100 to the radar control device 300.

Upon receiving the radar detection result, the radar control device 300 determines the distance and angle of the detected object included in the radar detection result (that is, the relative distance and angle with respect to the radar device 100), and the radar device that is the source of the radar detection result. The position information of the detected object is calculated based on the position information of 100. Furthermore, the radar control device 300 identifies several camera devices 120 in the vicinity of the detected object based on the calculated positional information of the detected object and the positional information of each radar device 100 (step S102). For example, four camera devices 120 are identified in order of proximity to the position of the detected object. In the case of camera arrangement as shown in FIGS. 5 and 6, four camera devices 120 surrounding the detection object are specified. Note that this method is just an example, and the camera device 120 may be identified using other methods. For example, several camera devices 120 may be set in advance for each block into which the monitoring target area is divided, and the camera device 120 set for the block in which the detected object is located may be specified.

The radar control device 300 controls each of the identified camera devices 120, adjusts the angle of view and focus, and causes the detected object to be photographed (step S103). Images captured by these camera devices 120 are transmitted to the radar control device 300. The radar control device 300 performs image processing using the plurality of captured images received from each of the identified camera devices 120, and generates an object shape image representing the shape of the detected object (step S104). The radar control device 300 transmits the generated object shape image to the display device 400, and displays it on the display device 400 (step S105).

Note that in the above explanation, an example was shown in which image processing is performed on a plurality of images obtained by a plurality of camera devices 120, but information on reflected wave power by the radar device 100 is used to generate an object shape image. It is also possible. This will be explained below with reference to FIG.

FIG. 12 shows the coordinate system of the radar device 100 rotating in the horizontal direction and the object X existing there. When the position of the radar device 100 is set as the origin, the position of the object X can be determined based on the distance and angle to the object X. At this time, if the resolution in the distance direction and angular direction is set to be sufficiently small for the size of the object . In the example of FIG. 12, the reflected wave power from the grid point of the black circle corresponding to the area of the object X is acquired. Therefore, by analyzing the reception result of the reflected wave power, it is possible to specify the size of the object as seen from the radar device 100. It is also possible to specify the approximate shape of the object.

Therefore, by using not only the object shape image obtained using the camera device 120 but also the object size information obtained using the radar device 100, it is possible to generate an object shape image that is even closer to the actual shape. becomes possible. In the example of FIG. 6, four radar devices 100A, 100B, 100C, and 100D specify the object size viewed from each direction. Although only one radar device 100 may be used to specify the object size, it is possible to specify the object size more accurately by using a larger number of radar devices 100. Thereby, the difference between the object shape image transmitted to the worker and the actual object shape can be reduced, and the search time can be shortened.

Further, the radar device 100 can also specify the approximate object shape of the detected object X, as shown in FIG. 12. Therefore, it is also possible to generate an object shape image using only the radar device 100 without using the camera device 120. In this case, the accuracy of the object shape image is lower than when using the camera device 120, but the system can be simplified and cost reduced. Of course, the object shape image may be generated by combining the object shape obtained using the camera device 120 and the object shape obtained using the radar device 100.

Here, since the radar system of this example uses a plurality of radar devices 100, one radar control device 300 controls the radio wave emission direction of each radar device 100 in order to prevent interference between the radar devices 100. Controls radio wave emission/stop timing. A radar system that monitors a wide area requires a large number of radar devices 100, but it may not be possible to secure an optical fiber cable to connect all the radar devices 100 to one radar control device 300.

In this case, it becomes necessary to additionally install another radar control device 300, but simply adding the radar control device 300 does not prevent interference between radar devices 100 connected to different radar control devices 300. I can't. Therefore, in this example, in order to prevent interference between the radar devices 100 connected to different radar control devices 300, a mechanism is provided to synchronize the plurality of radar control devices 300 with each other. The mechanism will be explained below.

FIG. 13 shows a first configuration example in which a plurality of radar control devices 300 are synchronized. The system in the figure includes a radar control device 300A that controls multiple radar devices 100 installed on one side of the road surface, a radar control device 300B that controls multiple radar devices 100 installed on the other side of the road surface, and a radar control device 300B that controls multiple radar devices 100 installed on the other side of the road surface. and a synchronous processing device 500 connected to the synchronous processing device 500.

The synchronization processing device 500 transmits a synchronization signal to the radar control device 300A and the radar control device 300B. The radar control device 300A controls the radar device 100 connected to the radar control device 300A at a preset timing according to the synchronization signal received from the synchronization processing device 500. Further, the radar control device 300B controls the radar device 100 connected to the radar control device 300B at a preset timing according to the synchronization signal received from the synchronization processing device 500. That is, the radar control device 300A and the radar control device 300B control the radar device 100 under their control in a mutually synchronized state. At this time, the radio wave irradiation direction and radio wave emission/stop timing are controlled so that the radio waves of each radar device 100 do not enter other radar devices 100. Thereby, interference between radar devices 100 connected to different radar control devices 300 can be prevented.

FIG. 14 shows a second configuration example in which a plurality of radar control devices 300 are synchronized. The system in the figure includes a radar control device 300A that controls multiple radar devices 100 installed on one side of the road surface, and a radar control device 300B that controls multiple radar devices 100 installed on the other side of the road surface. . Further, the radar control device 300A includes a GNSS (Global Navigation Satellite System) receiver 520, and the same applies to the radar control device 300B. The GNSS receiver 520 has a function of outputting accurate time information obtained from GNSS satellites.

Radar control device 300A controls radar device 100 connected to radar control device 300A at preset timing according to time information output from GNSS receiver 520. Further, the radar control device 300B controls the radar device 100 connected to the radar control device 300B at a preset timing according to the time information output from the GNSS receiver 520. That is, the radar control device 300A and the radar control device 300B control the radar device 100 under their control in a mutually synchronized state. At this time, the radio wave irradiation direction and radio wave emission/stop timing are controlled so that the radio waves of each radar device 100 do not enter other radar devices 100. Thereby, interference between radar devices 100 connected to different radar control devices 300 can be prevented.

As described above, the radar system of this example has a radar device 100 that detects objects existing on the road surface, which is a monitoring target area, and is installed at different positions, so that objects detected by the radar device 100 can be viewed from the own position. The display device 400 includes a plurality of sensor devices 200 that acquire shape information obtained by the plurality of sensor devices 200, and a display device 400 that displays an object shape image based on the plurality of shape information acquired by the plurality of sensor devices 200. In this way, by processing a plurality of pieces of shape information obtained by viewing the detected object from different directions, it becomes possible to display an object shape image that is closer to the actual shape. Therefore, according to the radar system of this example, it is possible to more accurately capture the shape of the object detected by the radar device.

Here, the shape information used to generate the object shape image can be acquired by the radar device 100 and/or camera device 120 included in the sensor device 200. That is, the shape information used to generate the object shape image may be an image taken by the camera device 120, may be the object shape specified by the radar device 100, or may be a combination thereof.

Further, in the radar system of this example, when a plurality of radar control devices 300 are used, these devices are synchronized by the synchronization processing device 500 or the GNSS receiver 520. Therefore, according to the radar system of this example, interference between radar devices 100 connected to different radar control devices 300 can be prevented.

Although the present invention has been described above based on one embodiment, it goes without saying that the present invention is not limited to the wireless communication system described herein, and can be widely applied to other wireless communication systems.
Further, the present invention can be provided, for example, as a method including technical procedures related to the above processing, a program for causing a processor to execute the above processing, and a storage medium that stores such a program in a computer-readable manner. is also possible.

It should be noted that the scope of the present invention is not limited to the exemplary embodiments shown and described, but also includes all embodiments that provide equivalent effects to the object of the present invention. Moreover, the scope of the invention may be defined by any desired combinations of specific features of each and every disclosed feature.

INDUSTRIAL APPLICATION This invention can be utilized for the radar system which detects the object which exists in the monitoring target area by a radar device.

100: radar device, 101: FMCW transmission source, 102: power divider, 103: transmission power amplifier, 104: transmission antenna, 105: reception antenna, 106: reception power amplifier, 107: mixer, 108: signal processing unit, 120: Camera device, 200: Sensor device, 300: Radar control device, 400: Display device, 500: Synchronization processing device, 520: GNSS receiver

Claims (6)

In a radar system that uses a radar device to detect objects in a monitored area,
a plurality of object shape acquisition devices each installed at a different location and each acquiring shape information of the object detected by the radar device viewed from a different direction ;
a display device that displays an object shape image based on the plurality of shape information acquired by the plurality of object shape acquisition devices ,
When an object existing in the monitoring target area is detected by the radar device, the position information of the object detected by the radar device is shared with the radar system, and the shapes of the plurality of objects are determined based on the position information of the object. Acquisition of shape information of the object after each of the two or more object shape acquisition devices specified from among the acquisition devices adjusts the direction to match the location of the object based on the position information of the object. A radar system characterized in that it is controlled to perform . The radar system according to claim 1,
A radar system characterized in that the plurality of object shape acquisition devices include a camera device. The radar system according to claim 1,
A radar system, wherein the plurality of object shape acquisition devices include a radar device. The radar system according to claim 1,
a first radar control device that controls the operation of the first radar device; a second radar control device that controls the operation of the second radar device; and the first radar control device and the second radar control device. and a synchronization processing device that transmits a synchronization signal to the device,
The first radar control device controls the operation of the first radar device at a timing according to a synchronization signal received from the synchronization processing device,
The radar system is characterized in that the second radar control device controls the operation of the second radar device at a timing according to a synchronization signal received from the synchronization processing device. The radar system according to claim 1,
A first radar control device that controls the operation of the first radar device, and a second radar control device that controls the operation of the second radar device,
The first radar control device and the second radar control device each have a GNSS receiver that outputs time information obtained from a GNSS satellite,
The first radar control device controls the operation of the first radar device at a timing according to time information output from the GNSS receiver,
The radar system is characterized in that the second radar control device controls the operation of the second radar device at a timing according to time information output from the GNSS receiver. In an object detection method performed by a radar system that uses a radar device to detect objects existing in a monitored area,
acquiring a plurality of shape information of the object detected by the radar device viewed from different directions by a plurality of object shape acquisition devices installed at different points ;
displaying an object shape image based on the plurality of shape information on a display device ,
In the acquiring step, when an object existing in the monitoring target area is detected by the radar device, the position information of the object detected by the radar device is shared with the radar system, and the position information of the object is shared based on the position information of the object. After each of the two or more object shape acquisition devices specified from the plurality of object shape acquisition devices adjusts the direction to match the location of the object based on the position information of the object, An object detection method characterized in that the object detection method is controlled to obtain shape information of the object .

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