Person detection device, and person detection method

Abstract

To provide a person detection device capable of improving the accuracy of positional detection of a person, and a person detection method.SOLUTION: A person detection device in a disclosed embodiment includes: an ultrasonic sensor that receives reflected waves of transmitted ultrasound; and a person recognition circuit that is configured so as to, when the reflected wave contains multiple peaks, determine whether the multiple position coordinates identified from the multiple peaks indicate multiple moving parts that move differently from each other when a person moves.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a person detection device and a person detection method. [Background technology]

[0002] 2. Description of the Related Art There is known a technique for detecting a person present around a vehicle by using an ultrasonic sensor mounted on the vehicle.

[0003] For example, Patent Document 1 discloses a technology in which a correlation waveform is calculated from received waves received by a distance sensor such as an ultrasonic sensor, and if multiple peaks are present in the correlation waveform, it is determined that a person is present because the multiple peaks are reflected waves from multiple parts of the person. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7101896 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the technology disclosed in Patent Document 1, the part of the person to be detected that reflects the ultrasonic waves depends on the posture of the person to be detected, so the ultrasonic wave reflection points vary without uniformity, which can make it difficult to accurately detect the position of the person to be detected.

[0006] The present disclosure has been made in consideration of the above circumstances, and contributes to providing a human detection device and a human detection method that can improve the accuracy of detecting the position of a person. [Means for solving the problem]

[0007] One aspect of the human detection device disclosed herein includes an ultrasonic sensor that receives reflected waves of transmitted ultrasonic waves, and a human detection circuit that, if the reflected waves contain multiple peaks, determines whether multiple position coordinates identified from the multiple peaks indicate multiple moving parts that move differently from each other when the person moves.

[0008] In one aspect of the person detection method of the present disclosure, an ultrasonic sensor transmits ultrasonic waves and receives reflected waves of the ultrasonic waves, and a person determination circuit, if the reflected waves contain multiple peaks, determines whether multiple position coordinates identified from the multiple peaks indicate multiple moving parts that move differently from each other when the person moves. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a human detection device and a human detection method that can improve the accuracy of detecting the position of a person. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing an example of a vehicle to which the human detection device of this embodiment is applied. [Figure 2] FIG. 2 is a block diagram showing an example of the functional configuration of the human detection device (vehicle) of this embodiment. [Figure 3] FIG. 3 is a block diagram showing an example of a detailed configuration of the ultrasonic sensor of this embodiment. [Figure 4] FIG. 4 is a block diagram showing an example of the hardware configuration of the control device of this embodiment. [Figure 5] FIG. 5 is a diagram showing an example of a human detection scene assumed in this embodiment. [Figure 6] FIG. 6 is a diagram showing an example of a verification result of the degree of variation in reflection points expected when ultrasonic waves are transmitted to both feet of a pedestrian. [Figure 7] FIG. 7 is a diagram showing an example of a doll imitating a pedestrian used in the verification of FIG. [Figure 8]FIG. 8 is a diagram showing a comparative example of the degree of dispersion of reflection points when ultrasonic waves are reflected by both feet of a person and when they are reflected by a pole. [Figure 9] FIG. 9 is a diagram showing an example of a method for calculating the reference coordinates in this embodiment. [Figure 10] FIG. 10 is a diagram showing the relationship between the reference coordinates calculated in FIG. 9 and the person. [Figure 11] FIG. 11 is a flowchart showing an example of the collision avoidance process performed by the human detection device of this embodiment. [Figure 12] FIG. 12 is a flowchart showing an example of the person detection process described with reference to FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present disclosure (hereinafter simply referred to as "the present embodiment") will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the following embodiment. Furthermore, the following embodiment and modified examples can be combined as appropriate.

[0012] First, the external configuration of a vehicle to which the human detection device of this embodiment is applied will be described.

[0013] FIG. 1 is a schematic diagram showing an example of a vehicle 1 to which a human detection device 100 according to the present embodiment is applied. As shown in FIG. 1, the vehicle 1 includes a plurality of ultrasonic sensors 10, a plurality of image capturing devices 30, a plurality of radars 40, and a control device 90. The human detection device 100 detects objects such as people present around the vehicle 1 using the ultrasonic sensors 10, and includes at least the ultrasonic sensors 10 and the control device 90. In the present embodiment, a case in which the human detection device 100 is applied to the vehicle 1 will be described as an example, but the present invention is not limited to this.

[0014] The ultrasonic sensor 10 is mounted on the vehicle 1 and is a sensor that detects objects such as people present around the vehicle 1. Specifically, the ultrasonic sensor 10 transmits ultrasonic waves and receives reflected waves of the transmitted ultrasonic waves. In this embodiment, the ultrasonic sensor 10 has a detection range of, for example, several centimeters to several meters, and detects the presence or absence of an object at a relatively short distance and the distance to the object. The ultrasonic sensor 10 has a wave transmitting function that transmits ultrasonic waves of, for example, 20 kHz to 100 kHz as transmitted waves, and a wave receiving function that receives ultrasonic waves reflected by an object as reflected waves.

[0015] Although details will be described later, the ultrasonic sensor 10 of this embodiment detects a person by detecting the lower half of the body (both legs) of the person present around the vehicle 1. For this reason, the ultrasonic sensor 10 of this embodiment has a narrower vertical directivity characteristic than existing ultrasonic sensors, and the directivity characteristic is set so as to detect the lower half of the body of a person present around the vehicle 1. The directivity characteristic can be strengthened, for example, by increasing the frequency of the ultrasonic waves, but is not limited to this.

[0016] In this embodiment, the vehicle 1 is equipped with ultrasonic sensors 10RL, 10RLC, 10RRC, 10RR, 10FL, 10FLC, 10FRC, and 10FR as ultrasonic sensors 10. These ultrasonic sensors 10 are provided at different positions on the vehicle 1. The detection ranges of the ultrasonic sensors 10 are adjusted so that at least a portion of the ranges do not overlap.

[0017] The ultrasonic sensors 10RL, 10RLC, 10RRC, and 10RR are provided in the rear portion of the vehicle 1. The ultrasonic sensor 10RL is provided in the left corner of the rear portion of the vehicle 1. The ultrasonic sensor 10RLC is provided near the left center of the rear portion of the vehicle 1. The ultrasonic sensor 10RRC is provided near the right center of the rear portion of the vehicle 1. The ultrasonic sensor 10RR is provided in the right corner of the rear portion of the vehicle 1.

[0018] The detection range 20RL of the ultrasonic sensor 10RL, the detection range 20RLC of the ultrasonic sensor 10RLC, the detection range 20RRC of the ultrasonic sensor 10RRC, and the detection range 20RR of the ultrasonic sensor 10RR are arranged so that they do not overlap at least partially. The detection ranges 20 of the multiple ultrasonic sensors 10 in the rear portion may be arranged so that they overlap partially.

[0019] Ultrasonic sensor 10FL, ultrasonic sensor 10FLC, ultrasonic sensor 10FRC, and ultrasonic sensor 10FR are provided in the front portion of vehicle 1. Ultrasonic sensor 10FL is provided in the left corner portion of the front portion of vehicle 1. Ultrasonic sensor 10FLC is provided near the left center of the front portion of vehicle 1. Ultrasonic sensor 10FRC is provided near the right center of the front portion of vehicle 1. Ultrasonic sensor 10FR is provided in the right corner portion of the front portion of vehicle 1.

[0020] The detection ranges of the ultrasonic sensors 10FL, 10FLC, 10FRC, and 10FR are arranged so as to at least partially not overlap, as in the rear section (not shown). The detection ranges of the ultrasonic sensors 10 in the front section may also be arranged so as to partially overlap, as in the rear section.

[0021] The number and arrangement of the ultrasonic sensors 10 provided on the vehicle 1 are not limited to the above. For example, one or more ultrasonic sensors 10 may be provided on the side of the vehicle 1.

[0022] The image capturing device 30 captures an image of the surroundings of the vehicle 1 and outputs the captured image to the control device 90.

[0023] In this embodiment, the vehicle 1 is equipped with the imaging devices 30, namely, imaging device 30F and imaging device 30R. The imaging device 30F is provided in the front part of the vehicle 1 and obtains an image of the periphery of the front part of the vehicle 1. The imaging device 30R is provided in the rear part of the vehicle 1 and obtains an image of the periphery of the rear part of the vehicle 1. Note that the number and arrangement of the imaging devices 30 provided in the vehicle 1 are not limited to the above embodiment.

[0024] The radar 40 detects an object such as a person around the vehicle 1 and measures the distance to the object (the distance between the object and the vehicle 1). The radar 40 detects objects around the vehicle 1 by scanning millimeter waves, which are electromagnetic waves, for example.

[0025] In this embodiment, the vehicle 1 is equipped with radar 40F and radar 40R as radars 40. Radar 40F is provided in the front portion of the vehicle 1 and detects objects in the front portion of the vehicle 1 by scanning the periphery of the front portion of the vehicle 1. Radar 40R is provided in the rear portion of the vehicle 1 and detects objects in the rear portion of the vehicle 1 by scanning the periphery of the rear portion of the vehicle 1. Note that the number and arrangement of radars 40 provided in the vehicle 1 are not limited to the above-described form.

[0026] Next, the functional configuration of the human detection device (vehicle) of this embodiment will be described.

[0027] 2 is a block diagram showing an example of the functional configuration of the human detection device 100 (vehicle 1) according to this embodiment. As shown in FIG. 2, the human detection device 100 (vehicle 1) includes an ultrasonic sensor 10, an image capturing device 30, a radar 40, a G sensor 51, a steering angle sensor 53, a driving control unit 55, an operation unit 57, a meter computer 59, a storage unit 61, and a control device 90.

[0028] The ultrasonic sensor 10, the imaging device 30, the radar 40, the G sensor 51, the steering angle sensor 53, the driving control unit 55, the meter computer 59, the storage unit 61, and the control device 90 are communicatively connected via a bus 70. The bus 70 may be, for example, a local area network such as a CAN (Controller Area Network), but is not limited to this.

[0029] The ultrasonic sensor 10 detects an object within its detection range and outputs the detection result of the object to the control device 90. Note that an object is something that can be detected by the ultrasonic sensor 10. For example, an object may be a person or other object that generates a reflected wave that reflects the ultrasonic waves transmitted from the ultrasonic sensor 10.

[0030] Fig. 3 is a block diagram showing an example of a detailed configuration of the ultrasonic sensor 10 of this embodiment. As shown in Fig. 3, the ultrasonic sensor 10 includes a wave transmitting unit 12, a wave receiving unit 14, and a controller 16. The wave transmitting unit 12 and the wave receiving unit 14 are each connected to the controller 16 so as to be able to communicate with each other. Furthermore, the controller 16 is connected to a control device 90 so as to be able to communicate with each other.

[0031] The wave transmitting unit 12 transmits ultrasonic waves. The wave receiving unit 14 receives reflected waves that are generated when the ultrasonic waves hit an object and are reflected. The wave transmitting unit 12 and the wave receiving unit 14 transmit ultrasonic waves and receive reflected waves, for example, via piezoelectric elements or the like. The controller 16 controls the transmission timing, transmission period, and ultrasonic frequency of the ultrasonic waves transmitted from the wave transmitting unit 12 under instructions from the control device 90. The controller 16 also measures the time from when the ultrasonic waves are transmitted by the wave transmitting unit 12 to when the reflected waves are received by the wave receiving unit 14. The controller 16 outputs detection results, including the measurement time (TOF: Time of Flight) and the reflection intensity of the reflected waves received by the wave receiving unit 14, to the control device 90.

[0032] The imaging device 30 and the radar 40 have already been explained in FIG. 1, so explanations thereof will be omitted.

[0033] The G sensor 51 measures the speed and acceleration of the vehicle 1 and outputs the measurement results to the control device 90.

[0034] The steering angle sensor 53 detects the steering angle of the steering wheel provided on the vehicle 1 and outputs it to the control device 90 as steering angle information.

[0035] The driving control unit 55 is an ECU (Engine Control Unit) that controls the driving of the vehicle 1. The driving control unit 55 is communicably connected to an operation unit 57. The driving control unit 55 controls drive devices such as an engine and a motor of the vehicle 1, and controls transmission system devices such as a transmission of the vehicle 1, in accordance with operation information by the driver (passenger) received from the operation unit 57.

[0036] The operating unit 57 is operated by the driver. The operating unit 57 includes, for example, an ignition switch, a shift lever, an accelerator pedal, and a brake pedal. However, the operating unit 57 is not limited to these.

[0037] The driving control unit 55 controls the drive device and transmission system of the vehicle 1 according to operation information of the ignition switch, shift position information of the shift lever, accelerator pedal operation information of the accelerator pedal, and brake pedal information of the brake pedal.

[0038] The operation information of the ignition switch is, for example, information that indicates an instruction to supply power to each part of the electrical system of the vehicle 1 and an instruction to start the engine of the vehicle 1. Upon receiving the instruction to supply power to each part of the electrical system of the vehicle 1, the traveling control unit 55 starts supplying power to the electronic devices mounted on the vehicle 1. Furthermore, upon receiving the instruction to start the engine of the vehicle 1, the traveling control unit 55 starts the engine of the vehicle 1.

[0039] The shift lever shift position information is information that indicates the position of the shift lever, such as parking, reverse, neutral, or drive.

[0040] The meter computer 59 has an information notification function for passengers such as the driver. The information notification function includes, but is not limited to, a display function that displays information and a sound output function that outputs a sound representing the information. An example of the display function is a combination meter device that notifies by display. An example of the sound output function is an alarm sound generator that notifies by buzzer or voice.

[0041] The storage unit 61 stores various types of data. Examples of the storage unit 61 include, but are not limited to, at least one of a semiconductor memory element such as a RAM (Random Access Memory), a flash memory, a hard disk, and an optical disk. The storage unit 61 may be composed of one or more storage media.

[0042] The control device 90 controls each unit included in the human detection device 100 (vehicle 1).

[0043] Fig. 4 is a block diagram showing an example of the hardware configuration of the control device 90 of this embodiment. As shown in Fig. 4, the control device 90 has a CPU (Central Processing Unit) 81, a ROM (Read Only Memory) 83, a RAM 85, an I / F 87, etc., which are interconnected via a bus 89, and has a hardware configuration that utilizes an existing computer.

[0044] The CPU 81 is a calculation device that controls the control device 90 of this embodiment. The ROM 83 stores programs and the like that realize various processes by the CPU 81. The RAM 85 stores data used for various processes by the CPU 81. The I / F 87 is an interface for sending and receiving data.

[0045] The programs for executing various controls and various processes executed by the control device 90 of this embodiment are provided by being pre-installed in the ROM 83, etc. The programs executed by the control device 90 of this embodiment may be provided by being recorded in a computer-readable recording medium such as a CD-ROM, a flexible disk (FD), a CD-R, or a digital versatile disk (DVD) in a format that can be installed or executed by the control device 90.

[0046] Returning to Fig. 2, the description will continue. In this embodiment, among the various controls performed by the control device 90 described above, the person detection process using the detection results of the ultrasonic sensor 10 will be mainly described, but the control performed by the control device 90 is not limited to this. The person detection process is used, for example, for AEB (Autonomous Emergency Braking) or the like to avoid a collision with a pedestrian, but the use of the person detection process is not limited to this.

[0047] Note that, in the following, the person detection process of this embodiment will be described assuming a scene as shown in Fig. 5, but the scene in which the person detection process is performed is not limited to this. Fig. 5 is a diagram showing an example of a person detection scene assumed in this embodiment. In the example shown in Fig. 5, a vehicle 1 is traveling (backing up) in a reverse direction BD for backing into a parking space or the like, and a person P is walking in a walking direction WD so as to cross the traveling path of the vehicle 1, and a scene is shown in which there is a possibility of a collision between the vehicle 1 and the person P. Note that the vehicle 1 is traveling at a speed of, for example, 4 to 8 km / h, and the person P is walking at a speed of, for example, 3 to 5 km / h, but the present invention is not limited to this.

[0048] Furthermore, in the person detection process of this embodiment, a person is detected by transmitting ultrasonic waves from the ultrasonic sensor 10 so as to detect the lower half of the person's body. In the method disclosed in the aforementioned Patent Document 1, which part of the person to be detected from which the ultrasonic waves are reflected depends on the posture of the person, and therefore the reflection points of the ultrasonic waves vary inconsistently each time the person is detected, which may make it difficult to accurately detect the position of the person. For this reason, in this embodiment, the ultrasonic sensor 10 transmits ultrasonic waves so as to detect the lower half of the person to be detected, and receives reflected waves from both feet of the person to be detected, which results in consistent variation in the reflection points of the ultrasonic waves.

[0049] Fig. 6 is a diagram showing an example of the verification results of the degree of variation in reflection points expected when ultrasonic waves are transmitted to both feet of a pedestrian. Fig. 7 is a diagram showing an example of a doll D imitating a pedestrian used in the verification of Fig. 6. The verification shown in Fig. 6 was performed by placing the doll D (see Fig. 7) in an area R in an XY coordinate system with the ultrasonic sensor 10RLC provided on the vehicle 1 as the origin, with the right foot 201R and left foot 201L moving back and forth in the W direction to mimic the movement during walking.

[0050] 7, the doll D is supported by a support 211, and therefore performs the walking motion described above in the area R. The support 211 is made of a material that absorbs ultrasonic waves and does not reflect ultrasonic waves, for example, but is not limited to this.

[0051] In the verification shown in Fig. 6, the ultrasonic sensor 10RLC periodically transmits ultrasonic waves to the lower body of the doll D, which is walking as described above, in the area R. Therefore, in the verification results shown in Fig. 6, the reflection points when the ultrasonic waves transmitted from the ultrasonic sensor 10RLC are reflected by the right foot 201R and left foot 201L of the doll D are plotted as dots. Note that because the right foot 201R and left foot 201L of the doll D are moving back and forth, the reflection points plotted as dots are scattered within the area R, as shown in Fig. 6. However, because the walking of the doll D is performed around the center of its body, the reflection points are scattered around the fixed coordinates 203 (1.8, 1.3) that indicate the center position of the body of the doll D.

[0052] In this way, when ultrasonic waves are transmitted to detect the lower body (both legs) of a person to be detected, the reflection points of the ultrasonic waves are both legs of the person, and therefore vary uniformly with respect to the center of the person's body. Therefore, according to this embodiment, it is possible to track the reference position of the person to be detected each time the person to be detected is detected, and it is possible to improve the detection accuracy of the person's position even when the ultrasonic sensor 10 is used alone to detect the person.

[0053] 2, the control device 90 includes a wave transmission control unit 91, a detection result acquisition unit 92, a peak determination unit 93, a position coordinate calculation unit 94, a person determination unit 95 (an example of a person determination circuit), a reference coordinate calculation unit 96 (an example of a reference coordinate calculation circuit), an avoidance determination unit 97 (an example of an avoidance determination circuit), and a drive control unit 98.

[0054] Some or all of the functional units included in the control device 90 may be realized by, for example, causing a processing device such as the CPU 81 to execute a program, for example, by software, or by hardware such as an IC (Integrated Circuit), or by a combination of software and hardware. Note that at least some of the functional units included in the control device 90 may be mounted on an external information processing device communicably connected to the control device 90 via a network or the like.

[0055] The wave transmission control unit 91 controls the transmission of ultrasonic waves from each of the multiple ultrasonic sensors 10. In the following, wave transmission control of the ultrasonic sensors 10 by the wave transmission control unit 91 of this embodiment will be described using the ultrasonic sensors 10RL, 10RLC, 10RRC, and 10RR provided in the rear portion of the vehicle 1 as an example. However, the present invention is not limited to this, and the method described below can also be applied to ultrasonic sensors 10 provided in the front portion of the vehicle 1.

[0056] If ultrasonic waves are transmitted simultaneously from multiple ultrasonic sensors 10, it may be impossible to distinguish which ultrasonic sensor 10 transmitted the reflected wave, even if the reflected wave is received, which may result in a decrease in distance measurement accuracy. For this reason, in this embodiment, the wave transmission control unit 91 sequentially transmits ultrasonic waves from each of the multiple ultrasonic sensors 10 in a predetermined wave transmission order. For example, the wave transmission control unit 91 periodically causes each ultrasonic sensor 10 to sequentially transmit ultrasonic waves in the following cycle: ultrasonic sensors 10RL and 10RR, ultrasonic sensor 10RLC, and ultrasonic sensor 10RRC. Note that the ultrasonic sensors 10RL and 10RR are provided at the corners at both ends of the vehicle 1, respectively, and therefore there is little interference between them. Therefore, even if ultrasonic waves are transmitted simultaneously, there is little possibility that the distance measurement accuracy will decrease.

[0057] In the following, human detection processing by the ultrasonic sensor 10 will be described using the periodic transmission and reception of ultrasonic waves by the ultrasonic sensor 10RLC as an example, but the present invention is not limited to this.

[0058] The detection result acquisition unit 92 acquires the detection result output from the ultrasonic sensor 10RLC each time the ultrasonic sensor 10RLC transmits an ultrasonic wave. As described above, the detection result includes the measurement time from when the ultrasonic wave is transmitted until the reflected wave is received, and the reflection intensity of the reflected wave.

[0059] The peak determination unit 93 determines whether or not the reflected wave includes multiple peaks based on the reflection intensity of the reflected wave included in the detection result acquired by the detection result acquisition unit 92. For example, the peak determination unit 93 determines whether or not the reflected wave included in the detection result includes multiple portions (e.g., two portions) where the reflection intensity exceeds a threshold. If multiple portions where the reflection intensity exceeds the threshold exist, the peak determination unit 93 determines that the reflected wave includes multiple peaks, and if multiple portions do not exist, the peak determination unit 93 determines that the reflected wave does not include multiple peaks.

[0060] The position coordinate calculation unit 94 calculates position coordinates identified from peaks included in the reflected wave. When the reflected wave includes multiple peaks, the position coordinate calculation unit 94 calculates multiple position coordinates identified from the multiple peaks.

[0061] The position coordinate calculation unit 94 calculates the distance for a peak included in the reflected wave, for example, using the measurement time (the time until the peak is detected) included in the detection result acquired by the detection result acquisition unit 92. The position coordinate calculation unit 94 calculates the position coordinate of the reflection point of the reflected wave from the calculated distance, for example, using an existing triangulation method. More specifically, the position coordinate calculation unit 94 calculates the position coordinate of the reflection point of the reflected wave using the calculated distance, the position coordinate (origin) of the ultrasonic sensor 10RLC, and the previously calculated position coordinate of the reflection point, using an existing triangulation method. Note that when the reflected wave includes multiple peaks (for example, two peaks), the position coordinate calculation unit 94 calculates the position coordinate of the reflection point for each of the multiple peaks.

[0062] When the reflected wave received by the ultrasonic sensor 10RLC contains multiple peaks, the person determination unit 95 determines whether the multiple position coordinates identified from the multiple peaks indicate multiple moving parts that move differently from each other when the person moves.

[0063] Examples of multiple moving parts that move differently when a person moves include, but are not limited to, both feet, both hands, and a combination of both hands and feet. In the following, an example will be described in which the multiple moving parts that move differently when a person moves are both feet.

[0064] Specifically, when the peak determination unit 93 determines that the reflected wave contains, for example, two peaks, the person determination unit 95 determines whether the two position coordinates calculated by the position coordinate calculation unit 94 indicate both feet of a person.

[0065] For example, the person determination unit 95 determines whether the difference between two position coordinates is within a first distance, and if it is within the first distance, determines that the two position coordinates indicate both feet of a person, and if it exceeds the first distance, determines that the two position coordinates do not indicate both feet of a person. The first distance is, for example, a distance based on the stride length of a person when walking, such as, but not limited to, 100 cm. If the difference between the two position coordinates exceeds the first distance, the person determination unit 95 determines that the two position coordinates do not indicate both feet of a person, and that the object having the detected reflection point is not a person.

[0066] Furthermore, for example, the person determination unit 95 determines whether the absolute value of the difference between the two previous position coordinates identified from the previously received reflected waves and the difference between the two latest position coordinates is equal to or greater than a second distance. If the absolute value of the difference is equal to or greater than the second distance, the person determination unit 95 determines that the latest two position coordinates indicate both feet of a person, and if the absolute value of the difference is less than the second distance, it determines that the latest two position coordinates do not indicate both feet of a person.

[0067] The second distance is used to determine whether the two most recent position coordinates indicate both legs of a person or a pole (rubber pole) on the road. If the two most recent position coordinates indicate a pole on the road, the pole is fixedly placed on the road, so the variation in the reflection point is small, but variation can occur. Therefore, the person determination unit 95 determines that the object is a pole if the absolute value of the difference between the previous two position coordinates and the difference between the latest two position coordinates is less than the variation in the reflection point of the pole, and determines that the object is both legs of a person if the absolute value is equal to or greater than the variation in the reflection point of the pole.

[0068] The degree of variation occurring at the reflection points of the poles varies depending on the distance from the ultrasonic sensor 10RLC. Therefore, the second distance is determined depending on the distance between the ultrasonic sensor 10RLC and the object that is the source of the reflected wave. For example, the second distance is determined depending on the distance to the reflection point calculated by the position coordinate calculation unit 94. For example, if the calculated distance to the reflection point is 1 m, the second distance can be set to 40 cm. This means that the degree of variation per pole is 20 cm, so the distance for two poles is 40 cm. For example, if the calculated distance to the reflection point is 2 m, the second distance can be set to 60 cm. This means that the degree of variation per pole is 30 cm, so the distance for two poles is 60 cm. For example, if the calculated distance to the reflection point is 3 m, the second distance can be set to 80 cm. This means that the degree of variation per pole is 40 cm, so the distance for two poles is 80 cm.

[0069] 8 is a diagram showing a comparative example of the degree of variation in reflection points when ultrasound is reflected by both feet of person P and when it is reflected by a pole. In the example shown in FIG. 8, N=1 indicates the latest position of person P's feet and the position of the pole, and N=2 indicates the previous position of person P's feet and the position of the pole. When the positions of person P's right foot 301R and left foot 301L are compared between N=1 and N=2, it is found that in N=1, right foot 301R and left foot 301L are apart, but in N=1, they are closed. Therefore, the absolute value of the difference between the difference in the position of right foot 301R and left foot 301L in the previous position (N=2) and the difference in the position of right foot 301R and left foot 301L in the latest position (N=1) is equal to or greater than the variation occurring in the reflection points of the pole, and it is determined that they are both feet of the person.

[0070] On the other hand, when comparing the positions of the poles 401 and 403 between N=1 and N=2, the relative positions of the poles 401 and 403 remain almost unchanged because they are fixedly positioned on the road. Therefore, the absolute value of the difference between the previous (N=2) position of the poles 401 and 403 and the latest (N=1) position of the poles 401 and 403 is nearly 0, which is less than the variation that occurs in the reflection points of the poles, and therefore they are determined to be poles.

[0071] The person determination section 95 may perform person determination using either one of the two types of person determination processing described above, or may perform person determination using both.

[0072] When the person determination unit 95 determines that a plurality of position coordinates indicate a plurality of movable parts, the reference coordinate calculation unit 96 calculates the reference coordinates of the person from the plurality of position coordinates. Specifically, because two position coordinates indicate both feet of person P, the reference coordinate calculation unit 96 determines that the detected object is person P and calculates the reference coordinates of person P from the two position coordinates. The reference coordinates may be, for example, the coordinate of the central axis of person P's body, but are not limited to this. The reference coordinate calculation unit 96 calculates the reference coordinates using, for example, a weighted average of the plurality of position coordinates, but the calculation method of the reference coordinates is not limited to this. The weights may be 0 or 1.

[0073] Fig. 9 is a diagram showing an example of a method for calculating the reference coordinates 303 in this embodiment. Fig. 10 is a diagram showing the relationship between the reference coordinates 303 calculated in Fig. 9 and person P. The example shown in Fig. 9 shows a right foot 301R and a left foot 301L of person P who has been determined to be a person by the person determination unit 95, as well as a reflection point 302R on the right foot 301R and a reflection point 302L on the left foot 301L, in an XY coordinate system with the ultrasonic sensor 10RLC provided on the vehicle 1 as the origin. The position coordinates of reflection point 302R are expressed as (X1, Y1), and the position coordinates of reflection point 302L are expressed as (X2, Y2).

[0074] In this embodiment, the reference coordinate calculation unit 96 calculates the reference coordinates using a weighted average, as described above. Here, if the weight for the coordinate value X1 is m1, the weight for the coordinate value X2 is m2, the weight for the coordinate value Y1 is m3, and the weight for the coordinate value Y2 is m4, the reference coordinates 303 can be calculated by Equation (1).

[0075]

number

[0076] As shown in FIG. 10, the reference coordinates 303 calculated from the right foot 301R (specifically, reflection point 302R) and left foot 301L (specifically, reflection point 302L) of person P are the coordinate values ​​of the central axis of person P's body, but are not limited to this.

[0077] The avoidance determination unit 97 determines whether or not the person P is an avoidance target based on the reference coordinates calculated by the reference coordinate calculation unit 96. For example, the avoidance determination unit 97 determines whether or not there is a possibility of collision with the person P from the reference coordinates calculated by the reference coordinate calculation unit 96, and determines that the person P is an avoidance target if the possibility of collision is high, and determines that the person P is not an avoidance target if the possibility of collision is low.

[0078] The drive control unit 98 controls the drive of the vehicle 1 based on the determination result of the avoidance determination unit 97. For example, the drive control unit 98 controls the traveling control unit 55 so as to avoid contact with the person P determined by the avoidance determination unit 97. Also, for example, the drive control unit 98 controls the traveling control unit 55 so as to travel while avoiding contact with the object determined by the avoidance determination unit 97. Also, for example, the drive control unit 98 controls the traveling control unit 55 so as to stop while avoiding contact with the object determined by the avoidance determination unit 97.

[0079] Furthermore, the drive control unit 98 may output information about the object determined by the avoidance determination unit 97 to the meter computer 59. For example, the drive control unit 98 may cause the meter computer 59 to display or output by voice information indicating that the determined object is located around the vehicle 1.

[0080] FIG. 11 is a flowchart showing an example of the collision avoidance process performed by the human detection device 100 of this embodiment.

[0081] First, the wave transmission control unit 91 causes the ultrasonic sensor 10 to transmit ultrasonic waves (step S101), and causes the ultrasonic sensor 10 to receive reflected waves of the transmitted ultrasonic waves (step S103).

[0082] Next, the control device 90 performs a person detection process using the detection result of the ultrasonic sensor 10 (step S105). The person detection process will be described with reference to FIG.

[0083] Next, the avoidance determination unit 97 checks whether or not a person has been detected by the person determination unit 95 (step S107). If a person has not been detected (No in step S107), the process ends.

[0084] On the other hand, when a person is detected by the person determination unit 95 (Yes in step S107), the avoidance determination unit 97 determines whether or not there is a possibility of a collision with the person (step S109) based on the reference coordinates calculated by the reference coordinate calculation unit 96. If there is no possibility of a collision (No in step S109), the process ends.

[0085] On the other hand, if the avoidance determination unit 97 determines that there is a possibility of a collision with a person (Yes in step S109), the drive control unit 98 performs avoidance processing, such as controlling the driving control unit 55, to avoid contact with the person (step S111).

[0086] FIG. 12 is a flowchart showing an example of the person detection process described with reference to FIG.

[0087] First, the position coordinate calculation unit 94 calculates the distance, for example, to a peak contained in the reflected wave, using the measurement time (the time until the peak is detected) contained in the detection result acquired by the detection result acquisition unit 92 (step S201).

[0088] Next, the position coordinate calculation unit 94 calculates the position coordinates of the reflection point of the reflected wave using the calculated distance, the position coordinates (origin) of the ultrasonic sensor 10RLC, and the position coordinates of the reflection point calculated previously, using an existing triangulation method (step S203).

[0089] If the reflected wave includes multiple (for example, two) peaks, the position coordinate calculation unit 94 performs the processes of steps S201 to S203 for each of the multiple peaks.

[0090] Next, the peak determination unit 93 determines whether or not the reflected wave includes multiple peaks based on the reflection intensity of the reflected wave included in the detection result acquired by the detection result acquisition unit 92 (step S205). If the reflected wave does not include multiple peaks (No in step S205), no person has been detected, and the process ends.

[0091] Next, if the peak determination unit 93 determines that the reflected wave contains multiple peaks (Yes in step S205), the person determination unit 95 determines whether the difference between the position coordinates is within the first distance (step S207). Note that if the difference between the position coordinates exceeds the first distance (No in step S207), the position coordinates do not indicate both legs of a person, and no person has been detected, so the process ends.

[0092] Next, if the difference between the position coordinates is within the first distance (Yes in step S207), the person determination unit 95 compares the difference between the previous position coordinates identified from the previously received reflected waves with the difference between the two most recent position coordinates (step S209), and determines whether the absolute value of both differences is equal to or greater than the second distance (step S211). Note that if the absolute value of both differences is less than the second distance (No in step S211), the position coordinates do not indicate both feet of a person, and no person has been detected, so the process ends.

[0093] Next, if the absolute value of the difference between the two is equal to or greater than the second distance (Yes in step S211), the person determination unit 95 determines that the latest position coordinates indicate both feet of a person, and determines that a person has been detected (step S213).

[0094] Subsequently, since the position coordinates indicate both feet of the person, the reference coordinate calculation unit 96 calculates the reference coordinates of the person from the position coordinates (step S215).

[0095] As described above, in this embodiment, ultrasonic waves are transmitted to detect the lower body (both legs) of the person to be detected, so the reflection points of the ultrasonic waves are the person's legs and vary uniformly based on the center of the person's body. Therefore, according to this embodiment, it is possible to track the reference position of the person to be detected each time the person to be detected is detected, and it is possible to improve the detection accuracy of the person's position even when the ultrasonic sensor 10 is used alone to detect the person.

[0096] (program) The program executed by the human detection device of the above embodiment is provided as a file in an installable or executable format stored on a computer-readable storage medium such as a CD-ROM, CD-R, memory card, DVD, or flexible disk (FD).

[0097] The program executed by the human detection device of the above embodiment may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. The program executed by the human detection device of the above embodiment may be provided or distributed via a network such as the Internet. The program executed by the human detection device of the above embodiment may be provided by being pre-installed in a ROM or the like.

[0098] The program executed by the human detection device of the above embodiment has a modular configuration for implementing the above-mentioned units on a computer. In terms of actual hardware, for example, the CPU reads the learning program from the HDD onto the RAM and executes it, thereby implementing the above-mentioned units on the computer.

[0099] As described above, according to the above embodiment, it is possible to improve the accuracy of detecting the position of a person.

[0100] The above-described embodiments merely illustrate examples of specific embodiments for implementing the present disclosure, and the technical scope of the present disclosure should not be construed as being limited by these embodiments. For example, the present disclosure can be implemented in various forms without departing from the gist or main features thereof. For example, the above-described embodiments and each of the above-described modifications may be appropriately combined in their respective constituent units. Furthermore, for example, some components may be deleted from all components in the above-described embodiments and each of the above-described modifications.

[0101] In the above description, the notation "... part" used for each component may be replaced with other notations such as "... assembly," "... circuit," "... device," "... unit," or "... module."

[0102] The present disclosure includes the following aspects.

[0103] (1) an ultrasonic sensor that receives reflected waves of transmitted ultrasonic waves; a person determination circuit that, when the reflected wave includes a plurality of peaks, determines whether a plurality of position coordinates identified from the plurality of peaks indicate a plurality of moving parts that move differently from each other when the person moves; A person detection device comprising:

[0104] (2) further comprising a reference coordinate calculation circuit that calculates reference coordinates of the person from the plurality of position coordinates when the plurality of position coordinates indicate the plurality of movable parts; The person detection device according to (1) above.

[0105] (3) The ultrasonic sensor is mounted on a vehicle and has a directional characteristic set to detect the lower body of a person present around the vehicle. the plurality of position coordinates are two position coordinates, the plurality of movable parts are the feet of the person; The person detection device according to (1) above.

[0106] (4) The person determination circuit determines that the two position coordinates indicate both feet of the person when a difference between the two position coordinates is within a first distance. The person detection device according to (3) above.

[0107] (5) When an absolute value of a difference between two previous position coordinates identified from a previously received reflected wave and the difference between the two position coordinates is equal to or greater than a second distance, the person determination circuit determines that the two position coordinates indicate both feet of the person. The person detection device according to (3) or (4) above.

[0108] (6) The second distance is determined according to the distance between the ultrasonic sensor and an object that is a source of the reflected wave. The person detection device according to (5) above.

[0109] (7) An avoidance determination circuit is further provided to determine whether the person is an avoidance target based on the reference coordinates. The person detection device according to (2) above.

[0110] (8) The reference coordinate calculation circuit calculates the reference coordinate using a weighted average of the plurality of position coordinates. The person detection device according to (2) above.

[0111] (9) The ultrasonic sensor transmits ultrasonic waves and receives reflected waves of the ultrasonic waves; a person determination circuit, when the reflected wave includes a plurality of peaks, determines whether or not a plurality of position coordinates identified from the plurality of peaks indicate a plurality of moving parts that move differently from each other when the person moves; Person detection method.

[0112] (10) A reference coordinate calculation circuit calculates a reference coordinate of the person from the plurality of position coordinates when the plurality of position coordinates indicate the plurality of movable parts. The person detection method according to (9) above.

[0113] (11) The ultrasonic sensor is mounted on a vehicle and has a directional characteristic set to detect the lower body of a person present around the vehicle, the plurality of position coordinates are two position coordinates, the plurality of movable parts are the feet of the person; The person detection method according to (9) above.

[0114] (12) The person determination circuit determines that the two position coordinates indicate both feet of the person when a difference between the two position coordinates is within a first distance. The person detection method according to (11) above.

[0115] (13) When an absolute value of a difference between two previous position coordinates determined from a previously received reflected wave and the difference between the two position coordinates is equal to or greater than a second distance, the person determination circuit determines that the two position coordinates indicate both feet of the person. The person detection method according to (11) or (12) above.

[0116] (14) The second distance is determined according to a distance between the ultrasonic sensor and an object that is a source of the reflected wave. The person detection method according to (13) above.

[0117] (15) An avoidance determination circuit determines whether the person is an avoidance target based on the reference coordinates. The person detection method according to (10) above.

[0118] (16) The reference coordinate calculation circuit calculates the reference coordinate using a weighted average of the plurality of position coordinates. The person detection method according to (10) above. [Explanation of symbols]

[0119] 1 vehicle 10, 10RLC ultrasonic sensor 12 Transmitting unit 14 Receiver section 16 Controllers 30 Imaging equipment 40 Radar 51 G sensor 53 Steering angle sensor 55 Travel control unit 57 Operation section 59 Meter Computer 61 Storage section 70 Bus 81 CPU 83 ROM 85 RAM 87 Interface 89 Bus 90 Control device 91 Transmission control section 92 Detection result acquisition unit 93 Peak judgment section 94 Position coordinate calculation unit 95 Person identification section 96 Reference coordinate calculation unit 97 Avoidance Judgment Section 98 Drive control unit 100 Person detection device

Claims

1. an ultrasonic sensor that receives reflected waves of transmitted ultrasonic waves; a person determination circuit that, when the reflected wave includes a plurality of peaks, determines whether a plurality of position coordinates identified from the plurality of peaks indicate a plurality of moving parts that move differently from each other when the person moves; A person detection device comprising:

2. a reference coordinate calculation circuit that calculates reference coordinates of the person from the plurality of position coordinates when the plurality of position coordinates indicate the plurality of movable parts; The human detection device according to claim 1 .

3. the ultrasonic sensor is mounted on a vehicle and has a directional characteristic set to detect the lower body of a person present around the vehicle; the plurality of position coordinates are two position coordinates, the plurality of movable parts are the feet of the person; The human detection device according to claim 1 .

4. the person determination circuit determines that the two position coordinates indicate both feet of the person when a difference between the two position coordinates is within a first distance; The human detection device according to claim 3 .

5. the person determination circuit determines that the two position coordinates indicate both feet of the person when an absolute value of a difference between two previous position coordinates identified from a previously received reflected wave and a difference between the two position coordinates is equal to or greater than a second distance; The human detection device according to claim 3 or 4.

6. The second distance is determined according to the distance between the ultrasonic sensor and an object that is a source of the reflected wave. The human detection device according to claim 5 .

7. further comprising an avoidance determination circuit that determines whether the person is an avoidance target based on the reference coordinates; The human detection device according to claim 2 .

8. the reference coordinate calculation circuit calculates the reference coordinate using a weighted average of the plurality of position coordinates. The human detection device according to claim 2 .

9. The ultrasonic sensor transmits ultrasonic waves and receives reflected waves of the ultrasonic waves. a person determination circuit, when the reflected wave includes a plurality of peaks, determines whether or not a plurality of position coordinates identified from the plurality of peaks indicate a plurality of moving parts that move differently from each other when the person moves; Person detection method.

10. a reference coordinate calculation circuit, when the plurality of position coordinates indicate the plurality of movable parts, calculates the reference coordinates of the person from the plurality of position coordinates; The person detection method according to claim 9 .

11. the ultrasonic sensor is mounted on a vehicle and has a directional characteristic set to detect the lower body of a person present around the vehicle; the plurality of position coordinates are two position coordinates, the plurality of movable parts are the feet of the person; The person detection method according to claim 9 .

12. the person determination circuit determines that the two position coordinates indicate both feet of the person when a difference between the two position coordinates is within a first distance; The person detection method according to claim 11.

13. the person determination circuit determines that the two position coordinates indicate both feet of the person when an absolute value of a difference between the difference between two previous position coordinates identified from the previously received reflected wave and the difference between the two position coordinates is equal to or greater than a second distance; The person detection method according to claim 11 or 12.

14. The second distance is determined according to the distance between the ultrasonic sensor and an object that is a source of the reflected wave. The person detection method according to claim 13.

15. an avoidance determination circuit determines whether the person is an object to be avoided based on the reference coordinates; The person detection method according to claim 10.

16. the reference coordinate calculation circuit calculates the reference coordinate using a weighted average of the plurality of position coordinates; The person detection method according to claim 10.

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