KR20210023556A - Apparatus and method for radar-based detection of living body in vehicle - Google Patents

Abstract

The present invention relates to a radar-based in-vehicle biosensing device and a method thereof. The present invention includes a controller (100) and a rear occupancy alert (ROA) radar module (300) for detecting rear-seat passengers. In an ROA signal processing step in the ROA radar module (300), the Doppler effect and phase change generated by the movement of an object are identified using a signal received from the detected object, and the presence of biosignals (e.g. respiration, heart rate, respiration change rate, heart rate variability, pulse, etc.) is measured. If it is determined as a biosignal, the ROA signal processing step determines whether there is a living organism inside a vehicle. Here, since living organism has a unique biosignal value according to species and age, it is possible to estimate the species and age of living organism as well as the existence of living organism by using the unique biosignal value.

Description

Apparatus and method for radar-based detection of living body in vehicle

The present invention relates to a rear occupancy alert (ROA) system, and more specifically, to an apparatus and method for detecting a living body in an ROA system using a micro-Doppler effect and a phase difference of a radar signal.

There is a Rear Occupancy Alert (ROA) system that provides warning or related information by monitoring objects remaining in the rear seat of the vehicle the driver has left to determine the presence or absence of occupants. Various methods are used to implement ROA, but ROA using non-contact radar sensor is representative. In the initial laser-based ROA, it was only determined whether an object exists in the rear seat of a vehicle, but recently, an ROA that determines whether a living body (living body) exists in the rear seat has appeared.

There is Korean Patent Application Publication No. 10-2018-0104369 A as an ROA technology that recognizes the state of the occupant using a radar. 1 is a schematic configuration diagram of an occupant state recognition device using a radar according to the prior art.

In FIG. 1, the occupant state recognition device according to the prior art applies a CFAR to the data acquired using the radar 100 to obtain a threshold value by applying a CFAR to the data acquired using the radar 100 in order to measure a bio-signal for recognizing whether the occupant is a living body. The number of times the values intersect is calculated using zero crossing. By dividing ½ of the calculated value by the time the subject was observed, the cycle of breathing can be obtained.

An object of the present invention is to propose an apparatus and method for efficiently detecting whether a rear seat occupant is a living organism (living body) such as a person or an animal in a radar-based rear seat occupant neglect warning (ROA) system.

In order to solve the above problem, the present invention determines whether the occupant is living by using a micro Doppler and a phase difference.

Specifically, according to an aspect of the present invention for solving the problem, means for emitting a radar signal, and receiving a reflected signal reflected by the radar signal by an object inside the vehicle; Means for determining the presence of an object inside the vehicle from the received reflected signal; And means for detecting a bio-signal from an object inside the vehicle whose existence is determined, and recognizing the object as a living body when there is a bio-signal.

Here, the means for recognizing the object as a living body may include a means for detecting a bio-signal by detecting a Doppler effect and a phase change of the reflected signal generated by the movement of the object inside the vehicle for which the existence is determined. .

In addition, the means for recognizing the object as a living body may include a means for estimating the species and age of the living body using the bio-signal.

In addition, according to another aspect of the present invention for solving the problem, generating a radar scan signal and emitting it to detect the inside of the vehicle and scan the rear seat of the vehicle; Receiving a signal in which the scan signal is reflected by an object inside the vehicle; Determining the presence of an object inside the vehicle from the received reflected signal; And detecting a bio-signal from an object inside the vehicle whose existence is determined, and recognizing the object as a living body when there is a bio-signal.

Here, the step of scanning the rear seat of the vehicle and the step of receiving the reflection signal may be repeatedly performed until data similar to an object inside the vehicle is identified a plurality of times.

In addition, the step of recognizing the object as a living body may include detecting a bio-signal by detecting a Doppler effect and a phase change of the reflected signal generated by the movement of the object inside the vehicle for which the existence is determined. .

In addition, the step of recognizing the object as a living body may include estimating a species and age of the living body using the bio-signal.

In the step of recognizing the object as a living body for accuracy of biometric recognition, it is preferable to determine the object as a living body when a bio-signal similar to the bio-signal detected from the object inside the vehicle for which the existence is determined is observed multiple times.

The configuration and operation of the present invention introduced above will become more apparent through specific embodiments described later with reference to the drawings.

The present invention can reduce the risk of accidents of passengers or animals left in a vehicle and cope with emergency situations. Unlike conventional techniques that obtain the cycle of biorespiration by dividing 1/2 of the biosignal value using zero crossing by the time of observing the object, the micro-Doppler effect and phase difference, and each peak of the biosignal data acquired It can be measured in real time using an interval between (peak) values.

Furthermore, the present invention makes it possible to actively respond to laws and regulations such as North America/Europe/Korea related to occupant detection, and thus, it is possible to secure market advantage. In addition, it is possible to preoccupy the automobile-related healthcare market by using the bio-signal detection technology included in the present invention.

1 is a configuration diagram of an occupant state recognition device using a radar shown in the prior art.
2A is a conceptual explanatory diagram of an apparatus and method for detecting a living body in a radar-based vehicle according to the present invention.
2B is a block diagram of an apparatus for detecting a living body in a radar-based vehicle according to the present invention.
3 is a flowchart of a process of a radar-based in-vehicle biometric sensing apparatus and method according to an embodiment of the method of the present invention.
4 is an exemplary diagram illustrating a breathing and heartbeat waveform of a living body according to a time period according to an embodiment of the present invention.

Advantages and features of the present invention, and a method of achieving them, will become apparent with reference to the embodiments described in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, only this embodiment is intended to complete the disclosure of the present invention, and those skilled in the art to which the present invention pertains. It is provided to fully inform the person of the scope of the invention, and the invention is defined by the description of the claims.

On the other hand, terms used in the present specification are for explaining examples and are not intended to limit the present invention. In this specification, the singular form also includes the plural form unless specifically stated in the phrase. As used herein, “comprise” or “comprising” means the presence of one or more other components, steps, actions and/or elements other than the recited elements, steps, actions and/or elements, or Does not exclude addition.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In adding reference numerals to elements of each drawing, even though they are indicated on different drawings, the same elements are assigned the same reference numerals as much as possible, and in describing the present invention, detailed descriptions of related known configurations or functions If the gist of the present invention may be obscured, a detailed description thereof will be omitted.

First, the concept of a radar-based vehicle occupant detection method and apparatus according to the present invention will be described with reference to FIGS. 2A and 2B. In this specification, it is indicated that the occupant is used interchangeably with the living body (human and animal).

Referring to the conceptual diagram of FIG. 2A, the present invention is schematically composed of a controller 100 (eg, an integrated body unit (IBU)) and an ROA radar module 300 for detecting a passenger in a rear seat. Communication between the controller 100 and the ROA radar module 300 may be performed using CAN communication. However, the communication method is not limited to CAN communication and can be diversified according to the development plan (LIN communication, etc.). In addition, the controller 100 may not be implemented as an IBU, but may be implemented as a separate unit.

In FIG. 2A, the controller 100 analyzes engine status, start on/off, door lock, or Fob information, and when the operation setting is met, the CAN or LIN communication method with the ROA radar module 300 The ROA function trigger signal 150 is transmitted. The ROA radar module 300 receives this and performs the ROA function, and then transmits the vehicle occupant presence information 160 to the controller 100 in a CAN or LIN communication method.

Looking at the configuration of the radar-based in-vehicle occupant detection device of the present invention in FIG. 2B in more detail, the in-vehicle occupant detection apparatus of the present invention includes a controller 100; It is composed of a ROA radar module 300 including an antenna and a transmission/reception unit (RF IC) 200 and a processing unit (MCU) 250. When the controller 100 sends the ROA trigger signal 150 to the ROA radar module 300, the ROA radar module 300 including the antenna and transceiver 200 and the MCU 250 performs a radar-based ROA function and , The rear seat detection information (whether or not there is a occupant in the vehicle) 160 is transmitted to the controller 100. Based on the received information, the controller 100 determines whether or not an alarm is an alarm. The antenna and transmission/reception unit 200 of the ROA radar module 300 radiates and receives radio waves for scanning the detection area, and the MCU 250 processes the received radar signal to perform a radar sensing function and The presence or absence of occupants in the vehicle is determined by detection logic.

Hereinafter, a method for detecting a living body in a vehicle of the present invention using the controller 100 and the ROA radar module 300 described above will be schematically described.

Basically, the in-vehicle biometric detection device of the present invention based on radar detects vital signs inside the vehicle through transmission/reception of RF signals. For this, it is necessary to be able to observe the entire interior of the vehicle, and depending on the function, it must be possible to detect only a specific region of interest. In addition, in the present invention, it is possible to control activation/deactivation (on/off) of the device by utilizing devices and functions that can be recognized by sensors inside the vehicle, such as IGN, Door lock, Fob, and the like.

The signal emitted by the radar is reflected back by objects inside the vehicle. Through changes in the intensity, frequency, and phase of the reflected signal, the material, position, and movement of the object are grasped. In this process, since the interior of the vehicle is a narrow space, a multi-pass (diffuse reflection) phenomenon may occur. In order to reduce this phenomenon and obtain accurate living body information inside the vehicle, the ROA radar module 300 performs a radar signal preprocessing operation. In addition, since the ROA radar module 300 may not detect false alarms and living organisms on the system, iterative tasks (repetition of laser scans and related operations) are performed to minimize the probability of system errors. After repetitively performing related tasks, if there is a high possibility that an object exists inside the vehicle, it is determined whether the signs of life are recognized in the object.

In the ROA signal processing step in the ROA radar module 300, biosignals (e.g., respiration, heart rate, respiration) are identified by detecting the Doppler effect and phase change caused by the movement of the object using the signal received from the detected object. Change rate, heart rate change rate, pulse rate, etc.) are measured. When it is determined as a bio-signal, the presence or absence of a living body inside the vehicle is determined in the ROA signal processing step. Here, since living organisms have their own bio-signal values according to species and age, it is possible to use this to estimate not only the existence of a living organism, but also the species and age of the living organism. More specifically, it is possible to distinguish between humans and animals by applying a classification algorithm using a range of eigenvalues of living organisms. In addition, in addition to bio-signals, size and movement can be used as features. Furthermore, it is also possible to estimate age through changes in eigenvalues according to age.

The ROA radar module 300 minimizes errors by repeating the entire process several times without determining the existence of a living organism with a single measurement. The result of the determination of the existence of living organisms observed by the ROA radar module 300 is sent to the in-vehicle controller (eg, IBU, ICU, etc.) 100. If necessary, the presence or absence of a living organism can be informed by sending an alarm to vehicle personnel using a horn, emergency light, or telematics.

Next, the method of the present invention will be described in detail with reference to FIG. 3.

3 is a flowchart of a process of a radar-based in-vehicle biometric sensing apparatus and method according to an embodiment of the method of the present invention.

S100: The controller 100 activates the operation of the ROA radar module 300 when the primary operating condition of the ROA radar module 300 (eg, when the primary notification and start are turned ON) is satisfied.

S110, S120: The ROA radar module 300 activated in step S100 generates an RF signal (ie, a scan signal) in step S110 and radiates it in step S120 to detect the interior of the vehicle and scan the rear seat of the vehicle.

S130: The scan signal (i.e., RF signal) emitted in steps S110 and S120 is reflected by the material inside the vehicle to change the shape of the signal, and in step S130, the ROA radar module 300 receives the modified signal. do. The radar signal is transmitted/received using a plurality of transmitting/receiving antennas.

S140: The ROA radar module performs radar signal preprocessing in S140. In the radar signal preprocessing step, detection information is obtained by using the difference between the transmitted signal and the received signal. To this end, since interference from an external signal other than a radar transmission signal may exist, the interference wave is eliminated. After removing the interference wave, distance information of the object is obtained through Fourier transform (FFT). The ROA radar module 300 that has obtained the distance information of the object acquires the angle information of the object based on the phase difference of the received signal using a plurality of transmitting and receiving antennas.

S150: The ROA radar module 300 repeats the above scan and radar signal preprocessing several times (n1 times) in preparation for a situation in which a singular value is received.

S155: If similar data is observed several times (n2 times) or more as a result of repeatedly performing the scan operation in step S150, the process proceeds to step S160 to perform signal processing. Otherwise, the scan and signal preprocessing process is repeated.

S160: The ROA radar module 300, which has performed several scan and signal preprocessing operations, performs ROA signal processing at S160. In the ROA signal processing step, the pre-processed signal is analyzed to determine whether there is a living organism inside the vehicle. To do this, first, objects (targets) other than existing vehicle structures (pre-data sheet, ceiling finish, interior lights, door trims, and other objects in the vehicle interior) are detected. Next, it examines whether a biological signal (e.g., respiration, heart rate, respiration rate, heart rate change rate, pulse rate, etc.) exists in the detected object. Judged by Then, this object is stored as biometric object data.

Here, the use of the micro-Doppler effect and phase change for observing the biological signal will be described in detail.

The Doppler effect refers to an effect that occurs when at least one of a wave source generating a wave and an observer observing the wave is in motion. Due to this effect, when the distance between the wave source and the observer decreases, the frequency of the wave is measured to be higher, and when the distance increases, the frequency of the wave is measured to be lower. In general, the Doppler effect was mainly used to grasp that movement such as the speed of a car or the speed of a golf ball is large, but recently it has begun to be used to observe small changes such as the movement of a person (i.e. ).

For example, in the case of living things, minute changes in the body occur due to breathing and heartbeat. In the present invention, a biosignal is extracted by measuring such a minute change using the micro-Doppler effect.

The phase of an electromagnetic wave with a frequency continuously changes according to the moving distance of the wave, and a small displacement can be measured using this change in phase. For example, in the case of a 77GHz electromagnetic wave, the wavelength is 3.89mm (speed/frequency of light = 3e8/77e9), and the phase changes 360 degrees over 1.19e-4 (1/77e9) seconds. That is, by calculating the phase difference between the previous signal and the current signal, it means that the change in the moving distance can be measured. In this way, biosignal information according to the present invention can be extracted by applying the above-described principle to the body.

4 is an exemplary diagram of a waveform of a living body's breathing and heartbeat according to a time period.

As described above, the minute movement changes in the body can be seen by the breathing and heartbeat of the living body. Therefore, when the movement phenomenon of a living body is measured through the ROA radar module 300, the resulting waveform as shown in FIG. 4 can be derived. At this time, the period of the bio-signal is grasped by using the peak value and the interval between the measured waveforms.

S170: In step S170, if the number of times that the steps S140 to S160 are repeated several times, that is, the number of times that a similar biological object is observed is multiple times (for example, n3 times), a passenger or animal left inside the vehicle Judging that there is a back. When it is determined that there are passengers or animals left inside the vehicle, the ROA radar module 300 transmits an alarm signal to the controller 100 to transmit a signal indicating the presence of the neglected passenger to the driver, and the above process is terminated. .

As described above, the present invention can be implemented in terms of a device or a method. In particular, a function or process of each component of the present invention is a digital signal processor (DSP), a processor, a controller, and an application program (ASIC). -Specific IC), programmable logic device (FPGA, etc.), at least one of other electronic devices, and can be implemented as a hardware element including a combination of these. It can also be implemented as software in combination with hardware elements or independently, which software can be stored on a recording medium.

Above, the configuration of the present invention has been described in detail through a preferred embodiment of the present invention, but those of ordinary skill in the art to which the present invention pertains, the present invention is disclosed in the present specification without changing the technical idea or essential features. It will be appreciated that it may be implemented in a specific form different from that of. It should be understood that the embodiments described above are illustrative in all respects and are not limiting. The scope of protection of the present invention is determined by the claims described later rather than the detailed description, and all changes or modifications derived from the scope of the claims and their equivalent concepts should be interpreted as being included in the technical scope of the present invention. .

Claims (15)

A device that detects a living body existing in a vehicle,
Means for emitting a radar signal and receiving a reflected signal in which the radar signal is reflected by an object inside the vehicle;
Means for determining the presence of an object inside the vehicle from the received reflected signal; And
A radar-based in-vehicle biometric detection device comprising means for detecting a bio-signal from an object in the vehicle whose existence is determined and recognizing the object as a living body when there is a bio-signal. The method of claim 1, wherein the means for determining the existence of an object inside the vehicle
A radar-based in-vehicle biometric detection device, characterized in that the presence of an object other than a vehicle structure is identified by using a change of one or more of the intensity, frequency, and phase of the reflected signal. The method of claim 1,
A radar-based in-vehicle biometric detection device further comprising a pre-processing means for correcting a multipath phenomenon of the reflected signal before determining the existence of an object inside the vehicle from the received reflected signal. The method of claim 1, wherein the means for recognizing the object as a living body
A radar-based in-vehicle biometric detection device comprising means for detecting a bio-signal by detecting a Doppler effect and a phase change of the reflected signal generated by the movement of an object inside the vehicle in which the existence of the object is determined. The method of claim 1, wherein the means for recognizing the object as a living body
A radar-based in-vehicle biometric detection device comprising a means for estimating a species and age of a living body using the bio-signal. The radar-based in-vehicle biometric detection device according to claim 1, further comprising a means for outputting the biometric recognition result. As a method of detecting a living body existing in a vehicle,
Generating a radar scan signal and emitting it to detect the interior of the vehicle and scan the rear seat of the vehicle;
Receiving a signal in which the scan signal is reflected by an object inside the vehicle;
Determining the presence of an object inside the vehicle from the received reflected signal; And
A radar-based in-vehicle biometric detection method comprising the step of detecting a bio-signal from an object inside the vehicle whose existence is determined and recognizing the object as a living body when there is a bio-signal. 8. The method of claim 7, wherein the radiation of the scan signal and reception of the reflected signal are performed using a plurality of antennas. The method of claim 7, further comprising pre-processing the reflected signal before determining the existence of an object inside the vehicle from the received reflected signal. The method of claim 9, wherein the pretreatment step
Removing interference waves from signals other than the radar scan signal,
Obtaining distance information of an object through Fourier transform (FFT), and
A radar-based in-vehicle biometric detection method comprising the step of acquiring angle information of an object based on the phase difference of the received reflected signal. The method of claim 7, wherein scanning the rear seat of the vehicle and receiving the reflection signal comprises:
A radar-based in-vehicle biometric detection method, characterized in that it is repeatedly performed until data similar to an object inside the vehicle is identified a plurality of times. The method of claim 7, wherein the step of recognizing the object as a living body
And detecting a bio-signal by detecting a Doppler effect and a phase change of the reflected signal generated by the movement of an object inside the vehicle for which the existence of the object is determined. The method of claim 7, wherein the step of recognizing the object as a living body
Radar-based in-vehicle biometric detection method comprising the step of estimating the species and age of the living body by using the bio-signal. The method of claim 7, wherein the step of recognizing the object as a living body
A radar-based in-vehicle biometric detection method, characterized in that when a bio-signal similar to a bio-signal detected from an object inside the vehicle whose existence is determined is observed multiple times, the object is determined as a living body. The method of claim 7, further comprising outputting a biometric recognition result of recognizing the object as a living body.

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