Heart rate and breath monitoring method based on millimeter wave radar

Abstract

The invention relates to the technical field of information processing, in particular to a heart rate and breath monitoring method based on millimeter wave radar, which comprises the following steps: determining whether a driver speaks or not; acquiring a first reflected wave signal; analyzing the first reflected wave signal; judging whether monitoring is abnormal or not; determining a second heartbeat frequency and a second breathing frequency; determining whether the driver is abnormal; and correcting the standard distance range. Head image recognition and mouth feature analysis are combined, it is ensured that heart rate and respiration monitoring is only carried out in the target static state, the heart rate and respiration monitoring efficiency is remarkably improved, the duration and the monitoring strategy of transmitted waves are dynamically adjusted according to the actual spacing distance between a driver and an emitter, target position changes are effectively adapted, and the accuracy of heart rate and respiration monitoring is improved. Monitoring errors are avoided, monitoring accuracy and effectiveness are improved, when wrong judgment occurs, the standard distance range is automatically corrected according to feedback, monitoring parameters are continuously optimized, monitoring precision is improved, and more reliable guarantee is provided for driving safety.

Description

Technical Field

[0001] The present invention relates to the field of information processing technology, and in particular to a heart rate and respiration monitoring method based on millimeter wave radar. Background Art

[0002] With the rapid development of modern transportation, the number of motor vehicles continues to grow. Road traffic accidents are still one of the important factors that seriously endanger human life and safety. Fatigue driving, as one of the main causes of traffic accidents, has become a major concern in the field of global traffic safety. Statistics show that traffic accidents caused by fatigue driving account for as much as 20%-30%, and the severity of accidents is often high, especially for long-distance transport, truck drivers and night drivers. Due to maintaining a high level of concentration for a long time, they are more prone to fatigue driving risks.

[0003] In recent years, millimeter-wave radar technology has shown great potential in the field of non-contact physiological monitoring. Compared with traditional sensors, millimeter-wave radar has the advantages of strong penetration, good anti-interference ability, and no radiation. It can accurately capture tiny movements of the human body and provide a new technical path for fatigue driving monitoring.

[0004] Patent document with publication number CN114366054A discloses a driver heart rate and respiratory rate detection system based on non-contact laser radar, including an in-vehicle laser radar monitoring device, an in-vehicle early warning device, an in-vehicle monitoring device and an Internet monitoring system; the laser radar can collect the driver's heart rate and respiratory rate in real time and contactlessly; the heart rate and respiratory rate processing and control device determines whether the received value is within the normal threshold range; if it is not within the normal range, a prompt is sent to the vehicle through the in-vehicle early warning device, and a warning light flashes at the same time; the Internet monitoring system can remotely view the driver's real-time video, monitor the driver's historical heart rate data and alarm data through the big data analysis of the Internet monitoring system, and can perform statistical analysis on the number of heart rate and respiratory rate alarms.

[0005] This shows the following problem: In the prior art, the driver's breathing monitoring may have low monitoring efficiency and accuracy due to the driver's own factors. Summary of the invention

[0006] To this end, the present invention provides a heart rate and respiration monitoring method based on millimeter wave radar, which is used to determine whether to monitor and determine the monitoring standard according to the driver's situation to overcome the problems of low monitoring efficiency and accuracy in the prior art.

[0007] To achieve the above object, the present invention provides a heart rate and respiration monitoring method based on millimeter wave radar, comprising:

[0008] Acquire a head image of the driver, acquire a mouth feature of the driver based on the head image, and determine whether the driver is speaking based on the mouth feature;

[0009] When it is determined that the driver is not speaking, using the millimeter wave radar to periodically transmit a transmission wave for a first time period to the driver;

[0010] Receiving a first reflected wave signal reflected after the transmission wave irradiates the driver;

[0011] Analyzing the first reflected wave signal to obtain a first heartbeat frequency and a first respiratory frequency;

[0012] Comparing the first heart rate and the first respiratory rate with the corresponding standard heart rate range and standard respiratory rate range to determine whether monitoring is abnormal;

[0013] When it is determined that the monitoring is abnormal, a standard distance between the driver and the transmitter is obtained to determine a standard distance range, the interval distance between the driver and the transmitter is monitored, the second duration is determined based on the interval distance, the first duration and the standard distance range, and a transmission wave lasting a second duration is transmitted to the driver, and a second heartbeat frequency and a second breathing frequency are determined according to a second reflected wave signal;

[0014] comparing the second heart rate and the second breathing rate with the corresponding standard heart rate range and standard breathing rate range to determine whether the driver is abnormal, and issuing an early warning when it is determined that the driver is abnormal;

[0015] After receiving the feedback of the early warning, if the feedback is an early warning error, the standard distance range is corrected to obtain a corrected distance range.

[0016] Furthermore, comparing the first heart rate and the first respiratory rate with corresponding standard heart rate ranges and standard respiratory rate ranges to determine whether monitoring is abnormal includes:

[0017] If the first heart rate is within the standard heart rate range and the first respiratory rate is within the standard respiratory rate range, then it is determined that the monitoring is normal;

[0018] If either the first heart rate is not within the standard heart rate range or the first respiratory rate is not within the standard respiratory rate range, monitoring abnormality is determined.

[0019] Further, obtaining the standard distance between the driver and the transmitter to determine the standard distance range includes:

[0020] Determine the standard distance between the driver and the transmitter for a preset time while the driver is speaking;

[0021] The standard distance range is determined based on the standard distance.

[0022] Further, determining the standard distance range based on the standard distance includes:

[0023] Performing statistical analysis on each of the standard distances to obtain an average value and a standard deviation of the standard distances;

[0024] The difference and sum of the mean value and the standard deviation are calculated to determine the standard distance range.

[0025] Further, the determining the second duration based on the interval distance, the first duration and a standard distance range includes:

[0026] Comparing the interval distance with the standard distance range, when the interval distance is not within the standard distance range during the monitoring time period reaching the first time period, stopping transmitting to the driver, and the second time period is the time from the transmission wave being transmitted to the stopping;

[0027] During the time period when the monitoring duration reaches the first duration, if the interval distance is within the standard distance range, the second duration is equal to the first duration.

[0028] Further, the correcting the standard distance range to obtain a corrected distance range includes:

[0029] Determine the difference value between each of the standard distances, compare the difference value with a preset standard difference value, and perform corresponding standard distance screening based on the comparison result;

[0030] If there is no abnormal difference value greater than the standard difference value in the difference values, the standard distance screening is to remove the suspicious distance corresponding to the maximum difference value in the difference values;

[0031] If there is an abnormal difference value greater than the standard difference value in the difference values, the standard distance screening is to remove each abnormal distance corresponding to the abnormal difference value;

[0032] Obtaining the corrected mean value and corrected standard deviation of each screening distance after standard distance screening;

[0033] The difference and the sum of the corrected mean value and the corrected standard deviation are calculated to determine the corrected distance range.

[0034] Further, determining the second heart rate and the second respiratory rate according to the second reflected wave signal includes:

[0035] Performing Fourier transform on the second reflected wave signal to obtain a second frequency domain signal;

[0036] The second frequency domain signal is analyzed to determine the second heartbeat frequency and the second breathing frequency.

[0037] Further, comparing the second heart rate and the second breathing rate with the corresponding standard heart rate range and standard breathing rate range to determine whether the driver is abnormal includes:

[0038] If the second heart rate is within the standard heart rate range and the second breathing rate is within the standard breathing rate range, it is determined that the driver is normal;

[0039] If either the second heart rate is not within the standard heart rate range or the second breathing rate is not within the standard breathing rate range, it is determined that the driver is abnormal.

[0040] Further, determining whether the driver is speaking based on the mouth feature includes:

[0041] Determining a change factor of the mouth feature within a preset time;

[0042] Comparing the change factor with a standard change threshold to obtain a comparison result;

[0043] Based on the comparison result, it is determined whether the driver is speaking, wherein:

[0044] If the change factor is less than the standard change threshold, it is determined that the driver is not speaking;

[0045] If the change factor is greater than or equal to the standard change threshold, it is determined that the driver is speaking.

[0046] Further, analyzing the first reflected wave signal to obtain a first heart rate and a first respiratory rate includes:

[0047] Performing Fourier transform on the first reflected wave signal to obtain a first frequency domain signal;

[0048] The first frequency domain signal is analyzed to determine the first heartbeat frequency and the first breathing frequency.

[0049] Compared with the prior art, the beneficial effect of the present invention lies in that, by combining head image recognition and mouth feature analysis, it ensures that heart rate and breathing monitoring is only performed when the target is stationary, thereby significantly improving the efficiency of heart rate and breathing monitoring. By dynamically adjusting the duration of the transmission wave and the monitoring strategy according to the actual interval distance between the driver and the transmitter, it effectively adapts to changes in the target position, avoids monitoring errors caused by target movement, and improves the accuracy and effectiveness of monitoring. By adopting multiple frequency comparisons and continuous monitoring strategies, abnormal conditions can be further verified and confirmed, greatly reducing the false alarm rate. When an erroneous judgment occurs, the standard distance range can be automatically corrected according to feedback, and the monitoring parameters can be continuously optimized to improve monitoring accuracy, providing more reliable protection for driving safety.

[0050] Furthermore, by accurately setting the standard heart rate range and the standard breathing rate range and establishing dual judgment criteria, the accuracy and sensitivity of heart rate and breathing abnormality detection can be significantly improved, and potential physiological risks of the driver can be captured in a timely manner, which helps prevent fatigue driving and ensure driving safety.

[0051] Furthermore, by collecting distance data multiple times while the driver is speaking, a more accurate and stable standard distance can be obtained, effectively reducing measurement errors and improving the reliability of distance measurement. By collecting distance while the driver is speaking, the exact distance between the driver and the radar when he is awake can be determined, making the standard distance range more representative and providing a more accurate reference benchmark for subsequent heart rate and respiratory monitoring.

[0052] Furthermore, by performing statistical analysis on the standard distance, the standard distance range between the driver and the millimeter-wave radar transmitter can be accurately determined. By performing statistical analysis on multiple collected standard distance data and calculating their average and standard deviation, the interference of individual abnormal data is effectively eliminated. The difference and sum of the average and standard deviation are calculated to obtain the precise distance range, which can better adapt to different driving environments and driver physical characteristics and improve the accuracy and applicability of heart rate and respiratory monitoring.

[0053] Furthermore, by dynamically monitoring the real-time interval distance between the driver and the transmitter and comparing it with the predetermined standard distance range in real time, the monitoring time of the transmission wave can be effectively adjusted. When the interval distance exceeds the standard distance range, the system immediately stops transmitting, which can not only improve the accuracy of monitoring, but also significantly reduce invalid radar wave emissions and reduce energy consumption. At the same time, when the interval distance is kept within the standard range, the original monitoring time is maintained to ensure the continuity and stability of monitoring, making the monitoring process more accurate, efficient and energy-saving.

[0054] Furthermore, by performing difference value analysis and outlier screening on the standard distance, noise data and extreme outliers in the monitoring process can be effectively removed, significantly improving the accuracy and reliability of distance measurement. By adopting dynamic thresholds and adaptive screening mechanisms, the distance range can be adjusted in real time according to the actual monitoring environment and data distribution, and the actual distance range between the driver and the equipment can be determined more accurately.

[0055] Furthermore, by performing Fourier transform on the second reflected wave signal, a second frequency domain signal is obtained, and the frequency domain signal is further analyzed to determine the second heart rate and the second breathing rate, the time domain signal is converted into a frequency domain signal, and the physiological characteristic signal is accurately extracted through spectrum analysis, which provides more reliable technical support for real-time monitoring of the driver's health status and improves the detection accuracy of heart rate and breathing rate.

[0056] Furthermore, by simultaneously detecting the heart rate and breathing rate and strictly comparing them with the preset standard frequency range, it is possible to timely discover and warn of the driver's potential abnormal state, significantly improving the accuracy and reliability of driver physiological status monitoring.

[0057] Furthermore, by accurately capturing and analyzing the dynamic changes of mouth features, the driver's speaking status can be identified efficiently and accurately. By calculating the change factor of the mouth features within a preset time and comparing it with the pre-set standard change threshold, the driver's language behavior can be monitored in real time, providing support for subsequent heart rate and respiratory monitoring and improving the accuracy of monitoring.

[0058] Furthermore, by performing Fourier transform on the first reflected wave signal and analyzing the frequency domain signal, the ability to accurately extract heart rate and respiratory rate can be significantly improved. Fourier transform can convert time domain signals into frequency domain signals, effectively extract heart rate and respiratory rate, and continuously and stably monitor the driver's physiological state without affecting his normal activities. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is a flow chart of a method for monitoring heart rate and respiration based on millimeter wave radar according to an embodiment of the present invention;

[0060] Figure 2 A flow chart for determining a standard distance range for an embodiment of the present invention;

[0061] Figure 3 A decision logic diagram for determining a corrected distance range according to an embodiment of the present invention;

[0062] Figure 4 The flowchart of determining whether the driver is speaking according to an embodiment of the present invention. DETAILED DESCRIPTION

[0063] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0064] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0065] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0066] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0067] See also Figure 1 ,like Figure 1 As shown, it is a flow chart of a heart rate and respiration monitoring method based on millimeter wave radar according to an embodiment of the present invention;

[0068] Specifically, the heart rate and respiration monitoring method based on millimeter wave radar provided in an embodiment of the present invention includes:

[0069] Acquire a head image of the driver, acquire a mouth feature of the driver based on the head image, and determine whether the driver is speaking based on the mouth feature;

[0070] When it is determined that the driver is not speaking, using the millimeter wave radar to periodically transmit a transmission wave for a first time period to the driver;

[0071] Receiving a first reflected wave signal reflected after the transmission wave irradiates the driver;

[0072] Analyzing the first reflected wave signal to obtain a first heartbeat frequency and a first respiratory frequency;

[0073] Comparing the first heart rate and the first respiratory rate with the corresponding standard heart rate range and standard respiratory rate range to determine whether monitoring is abnormal;

[0074] When it is determined that the monitoring is abnormal, a standard distance between the driver and the transmitter is obtained to determine a standard distance range, the interval distance between the driver and the transmitter is monitored, the second duration is determined based on the interval distance, the first duration and the standard distance range, and a transmission wave lasting a second duration is transmitted to the driver, and a second heartbeat frequency and a second breathing frequency are determined according to a second reflected wave signal;

[0075] comparing the second heart rate and the second breathing rate with the corresponding standard heart rate range and standard breathing rate range to determine whether the driver is abnormal, and issuing an early warning when it is determined that the driver is abnormal;

[0076] After receiving the feedback of the early warning, if the feedback is an early warning error, the standard distance range is corrected to obtain a corrected distance range.

[0077] The standard heart rate range is the heart rate range of the driver when he is awake, which is generally set to 60-100 times / minute. In the present embodiment, the standard heart rate range is 70-90 times / minute. The standard breathing rate range is the breathing rate range of the driver when he is awake, which is generally set to 12-20 times / minute. In the present embodiment, the standard breathing rate range is 14-18 times / minute. The feedback is the voice feedback, action feedback, etc. received from the driver after the driver is warned, as long as it can represent whether the driver approves the warning. The mouth feature is the distance between the upper and lower lips of the driver.

[0078] Specifically, whether the driver is talking is determined based on the mouth features recognized in the acquired head image. When it is determined that the driver is talking, it is determined not to monitor the driver's heart rate and breathing. When it is determined that the driver is not talking, the driver is periodically emitted a transmission wave for a first period of time to monitor his breathing and heart rate. According to the breathing rate and heart rate obtained by monitoring, it is possible to timely determine whether the driver is fatigued. During the periodic monitoring process, if a monitoring abnormality is detected, the driver is immediately monitored again to verify whether the driver is driving fatigued, or whether the driver's own movement affects the monitoring of the millimeter-wave radar, thereby determining a monitoring abnormality. A standard distance range between the driver and the transmitter is determined based on the standard distances between the driver and the transmitter when the driver is awake and talking, and the distance between the driver and the transmitting wave is measured when the driver is immediately monitored and verified. The invention discloses a method for monitoring the interval distance. If, during the time period when the continuous emission time of the emission wave reaches the first duration, when it is monitored that the interval distance between the driver and the emission wave exceeds the standard distance range, the irradiation is stopped immediately. If, during the time period when the continuous emission time of the emission wave reaches the first duration, the interval distance does not exceed the standard distance range, the irradiation is stopped when the second duration is reached. Whether the driver is abnormal is determined based on the second reflected wave signal emitted from the driver's body during the second duration from the start of irradiation to the stop of irradiation. When it is determined that the driver is abnormal, the driver is warned, and feedback from the driver is received after the warning. If the feedback is a warning error, it means that the standard distance range between the driver and the transmitter is incorrectly determined, and the driver's own movement still affects the monitoring of the heart rate and breathing, resulting in erroneous monitoring. Then, the standard distance range is corrected to obtain a corrected distance range, and then the heart rate and breathing are monitored and abnormalities are determined.

[0079] Specifically, by combining head image recognition and mouth feature analysis, it is ensured that heart rate and breathing monitoring is only performed when the target is stationary, which significantly improves the efficiency of heart rate and breathing monitoring. By dynamically adjusting the duration of the transmission wave and the monitoring strategy according to the actual distance between the driver and the transmitter, it can effectively adapt to changes in the target position, avoid monitoring errors caused by target movement, and improve the accuracy and effectiveness of monitoring. By adopting multiple frequency comparisons and continuous monitoring strategies, abnormal conditions can be further verified and confirmed, greatly reducing the false alarm rate. When an erroneous judgment occurs, the standard distance range can be automatically corrected according to feedback, and the monitoring parameters can be continuously optimized to improve monitoring accuracy, providing more reliable protection for driving safety.

[0080] Specifically, comparing the first heart rate and the first respiratory rate with the corresponding standard heart rate range and standard respiratory rate range to determine whether monitoring is abnormal includes:

[0081] If the first heart rate is within the standard heart rate range and the first respiratory rate is within the standard respiratory rate range, then it is determined that the monitoring is normal;

[0082] If either the first heart rate is not within the standard heart rate range or the first respiratory rate is not within the standard respiratory rate range, monitoring abnormality is determined.

[0083] During the specific implementation process, the standard heart rate range is 70-90 times / minute, the standard respiratory rate range is 14-18 times / minute, the first monitored heart rate is 100 times / minute, and the first monitored respiratory rate is 22 times / minute. The first heart rate is not within the standard heart rate range, and the first respiratory rate is not within the standard respiratory rate range, and the monitoring is judged to be abnormal.

[0084] Specifically, by accurately setting the standard heart rate range and the standard breathing rate range and establishing dual judgment standards, the accuracy and sensitivity of heart rate and breathing abnormality detection can be significantly improved, and potential physiological risks of drivers can be captured in a timely manner, which helps prevent fatigue driving and ensure driving safety.

[0085] Please continue reading Figure 2 ,like Figure 2 As shown, it is a flow chart of determining a standard distance range according to an embodiment of the present invention;

[0086] Specifically, obtaining the standard distance between the driver and the transmitter to determine the standard distance range includes:

[0087] Determine the standard distance between the driver and the transmitter for a preset time while the driver is speaking;

[0088] The standard distance range is determined based on the standard distance.

[0089] Specifically, a standard distance between the driver and the transmitter due to breathing changes within a certain preset time when the driver is speaking soberly is determined, and a standard distance range between the driver and the transmitter is determined based on the obtained standard distances.

[0090] Specifically, by collecting distance data multiple times while the driver is speaking, a more accurate and stable standard distance can be obtained, effectively reducing measurement errors and improving the reliability of distance measurement. By collecting distance while the driver is speaking, the exact distance between the driver and the radar when he is awake can be determined, making the standard distance range more representative and providing a more accurate reference benchmark for subsequent heart rate and respiratory monitoring.

[0091] Specifically, determining the standard distance range based on the standard distance includes:

[0092] Performing statistical analysis on each of the standard distances to obtain an average value and a standard deviation of the standard distances;

[0093] The difference and sum of the mean value and the standard deviation are calculated to determine the standard distance range.

[0094] During the specific implementation process, the standard distances obtained within the preset time period of 5 seconds are 0.50m, 0.51m, 0.505m, 0.501m, 0.507m, and 0.49m respectively. The calculated average value of the standard distance is 0.5019m, and the standard deviation is 0.0087m. The difference between the average and the standard deviation is 0.4932m, and the sum of the average and the standard deviation is 0.5106m. The standard distance range is 0.4932m-0.5106m.

[0095] Specifically, by conducting statistical analysis on the standard distance, the standard distance range between the driver and the millimeter-wave radar transmitter can be accurately determined. By conducting statistical analysis on multiple collected standard distance data and calculating their average and standard deviation, the interference of individual abnormal data can be effectively eliminated. The difference and sum of the average and standard deviation can be calculated to obtain the precise distance range, which can better adapt to different driving environments and driver physical characteristics and improve the accuracy and applicability of heart rate and respiratory monitoring.

[0096] Specifically, determining the second duration based on the interval distance, the first duration, and the standard distance range includes:

[0097] Comparing the interval distance with the standard distance range, when the interval distance is not within the standard distance range during the monitoring time period reaching the first time period, stopping transmitting to the driver, and the second time period is the time from the transmission wave being transmitted to the stopping;

[0098] During the time period when the monitoring duration reaches the first duration, if the interval distance is within the standard distance range, the second duration is equal to the first duration.

[0099] Specifically, when the transmission wave irradiation time reaches the first duration, if it is detected that the distance between the driver and the transmitter exceeds the standard distance range at a certain moment, the transmitter stops emitting transmission waves to the driver; if the distance is within the standard distance range when the transmission time reaches the first duration, the transmitter stops emitting transmission waves to the driver when the first duration is reached.

[0100] Specifically, by dynamically monitoring the real-time interval distance between the driver and the transmitter and comparing it with the predetermined standard distance range in real time, the monitoring time of the transmission wave can be effectively adjusted. When the interval distance exceeds the standard distance range, the system immediately stops transmitting, which can not only improve the accuracy of monitoring, but also significantly reduce invalid radar wave emissions and reduce energy consumption. At the same time, when the interval distance is kept within the standard range, the original monitoring time is maintained to ensure the continuity and stability of monitoring, making the monitoring process more accurate, efficient and energy-saving.

[0101] Please continue reading Figure 3 ,like Figure 3 As shown, it is a decision logic diagram for determining the correction distance range according to an embodiment of the present invention;

[0102] Specifically, the correcting the standard distance range to obtain a corrected distance range includes:

[0103] Determine the difference value between each of the standard distances, compare the difference value with a preset standard difference value, and perform corresponding standard distance screening based on the comparison result;

[0104] If there is no abnormal difference value greater than the standard difference value in the difference values, the standard distance screening is to remove the suspicious distance corresponding to the maximum difference value in the difference values;

[0105] If there is an abnormal difference value greater than the standard difference value in the difference values, the standard distance screening is to remove each abnormal distance corresponding to the abnormal difference value;

[0106] Obtaining the corrected mean value and corrected standard deviation of each screening distance after standard distance screening;

[0107] The difference and the sum of the corrected mean value and the corrected standard deviation are calculated to determine the corrected distance range.

[0108] Specifically, the standard difference value is the difference between the standard distances between the driver and the transmitter caused by normal breathing, which is generally set between 0.006m-0.01m. In this embodiment, the standard difference value is 0.08m. The two standard distances for calculating the abnormal difference are the abnormal distances corresponding to the abnormal difference values, and the two standard distances for calculating the maximum difference values ​​are the suspicious distances corresponding to the maximum difference values.

[0109] In the specific implementation process, the preset standard difference value is 0.008m, and the standard distances obtained within the preset time period of 5 seconds are 0.50m, 0.51m, 0.505m, 0.501m, 0.507m, and 0.49m respectively. The difference values ​​between the standard distances are calculated to be 0.01m, 0.005m, 0.004m, 0.006m, and 0.017m, of which 0.01m and 0.017m are both greater than the standard difference value of 0.008m, so 0.01m and 0.017m is the abnormal difference value. After removing the abnormal difference values ​​0.01m and 0.017m, the corresponding suspicious distances are 0.50m, 0.51m, 0.507m and 0.49m. The corrected mean values ​​of the screening distances 0.505m and 0.501m after removing the suspicious distances are 0.503m, and the corrected standard deviation is 0.002m. The difference between the corrected mean value and the corrected standard deviation is 0.501m, and the sum is 0.505m. The corrected distance range is 0.501m-0.505m.

[0110] Specifically, by performing difference value analysis and outlier screening on the standard distance, noise data and extreme outliers in the monitoring process can be effectively removed, significantly improving the accuracy and reliability of distance measurement. By adopting dynamic thresholds and adaptive screening mechanisms, the distance range can be adjusted in real time according to the actual monitoring environment and data distribution, and the actual distance range between the driver and the equipment can be determined more accurately.

[0111] Specifically, determining the second heart rate and the second respiratory rate according to the second reflected wave signal includes:

[0112] Performing Fourier transform on the second reflected wave signal to obtain a second frequency domain signal;

[0113] The second frequency domain signal is analyzed to determine the second heartbeat frequency and the second breathing frequency.

[0114] Specifically, the second reflected wave signal is converted into a frequency domain signal, the characteristic peaks of the heart rate and the characteristic peaks of the respiratory rate in the frequency domain signal are determined, and the frequencies corresponding to the peaks are determined, namely, the second heart rate and the second respiratory rate.

[0115] Specifically, the second frequency domain signal is obtained by performing Fourier transform on the second reflected wave signal, and the frequency domain signal is further analyzed to determine the second heart rate and the second breathing rate. The time domain signal is converted into a frequency domain signal, and the physiological characteristic signal is accurately extracted through spectrum analysis, which provides more reliable technical support for real-time monitoring of the driver's health status and improves the detection accuracy of heart rate and breathing rate.

[0116] Specifically, comparing the second heart rate and the second breathing rate with the corresponding standard heart rate range and standard breathing rate range to determine whether the driver is abnormal includes:

[0117] If the second heart rate is within the standard heart rate range and the second breathing rate is within the standard breathing rate range, it is determined that the driver is normal;

[0118] If either the second heart rate is not within the standard heart rate range or the second breathing rate is not within the standard breathing rate range, it is determined that the driver is abnormal.

[0119] During the specific implementation process, the standard heart rate range is 70-90 times / minute, the standard breathing rate range is 14-18 times / minute, the second heart rate obtained is 95 times / minute, and the second breathing rate is 20 times / minute. The second heart rate is not within the standard heart rate range, and the second breathing rate is not within the standard breathing rate range, and the driver is judged to be abnormal.

[0120] Specifically, by simultaneously detecting heart rate and breathing rate and strictly comparing them with the preset standard frequency range, it is possible to promptly detect and warn of potential abnormal conditions of the driver, significantly improving the accuracy and reliability of driver physiological status monitoring.

[0121] Please continue reading Figure 4 ,like Figure 4 As shown, it is a flow chart of determining whether the driver is speaking according to an embodiment of the present invention;

[0122] Specifically, determining whether the driver is speaking based on the mouth features includes:

[0123] Determining a change factor of the mouth feature within a preset time;

[0124] Comparing the change factor with a standard change threshold to obtain a comparison result;

[0125] Based on the comparison result, it is determined whether the driver is speaking, wherein:

[0126] If the change factor is less than the standard change threshold, it is determined that the driver is not speaking;

[0127] If the change factor is greater than or equal to the standard change threshold, it is determined that the driver is speaking.

[0128] Specifically, the change factor is the number of times the mouth feature changes within a preset time, and the standard change threshold is the minimum number of times the mouth feature changes within the preset time for judging that the driver is speaking.

[0129] During the specific implementation process, the standard change threshold is 3 times, and the mouth features within the preset time of 5 seconds are 10mm, 3mm, 8mm, 2mm, 9mm, 2mm, and the change factor is 5 times. The change factor is greater than the standard change threshold, and it is determined that the driver is speaking.

[0130] Specifically, by accurately capturing and analyzing the dynamic changes of mouth features, the driver's speaking status can be identified efficiently and accurately. By calculating the change factor of mouth features within a preset time and comparing it with the pre-set standard change threshold, real-time monitoring of the driver's language behavior can be achieved, providing support for subsequent heart rate and respiratory monitoring and improving the accuracy of monitoring.

[0131] Specifically, analyzing the first reflected wave signal to obtain a first heartbeat frequency and a first respiratory frequency includes:

[0132] Performing Fourier transform on the first reflected wave signal to obtain a first frequency domain signal;

[0133] The first frequency domain signal is analyzed to determine the first heartbeat frequency and the first breathing frequency.

[0134] Specifically, the first reflected wave signal is converted into a frequency domain signal, the characteristic peaks of the heart rate and the characteristic peaks of the respiratory rate in the frequency domain signal are determined, and the frequencies corresponding to the peaks are determined, namely, the first heart rate and the first respiratory rate.

[0135] Specifically, by performing Fourier transform on the first reflected wave signal and analyzing the frequency domain signal, the ability to accurately extract heart rate and respiratory rate can be significantly improved. Fourier transform can convert time domain signals into frequency domain signals, effectively extract heart rate and respiratory rate, and can continuously and stably monitor the driver's physiological state without affecting his normal activities.

[0136] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0137] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A heart rate and respiration monitoring method based on millimeter wave radar, characterized in that: include: Acquire a head image of the driver, acquire a mouth feature of the driver based on the head image, and determine whether the driver is speaking based on the mouth feature; When it is determined that the driver is not speaking, using the millimeter wave radar to periodically transmit a transmission wave for a first time period to the driver; Receiving a first reflected wave signal reflected after the transmission wave irradiates the driver; Analyzing the first reflected wave signal to obtain a first heartbeat frequency and a first respiratory frequency; Comparing the first heart rate and the first respiratory rate with the corresponding standard heart rate range and standard respiratory rate range to determine whether monitoring is abnormal; When it is determined that the monitoring is abnormal, a standard distance between the driver and the transmitter is obtained to determine a standard distance range, the interval distance between the driver and the transmitter is monitored, the second duration is determined based on the interval distance, the first duration and the standard distance range, and a transmission wave lasting a second duration is transmitted to the driver, and a second heartbeat frequency and a second breathing frequency are determined according to a second reflected wave signal; comparing the second heart rate and the second breathing rate with the corresponding standard heart rate range and standard breathing rate range to determine whether the driver is abnormal, and issuing an early warning when it is determined that the driver is abnormal; After receiving the feedback of the early warning, if the feedback is an early warning error, the standard distance range is corrected to obtain a corrected distance range.

2. The heart rate and respiration monitoring method based on millimeter wave radar according to claim 1, characterized in that: The comparing the first heart rate and the first respiratory rate with the corresponding standard heart rate range and standard respiratory rate range to determine whether monitoring is abnormal includes: If the first heart rate is within the standard heart rate range and the first respiratory rate is within the standard respiratory rate range, then it is determined that the monitoring is normal; If either the first heart rate is not within the standard heart rate range or the first respiratory rate is not within the standard respiratory rate range, monitoring abnormality is determined.

3. The heart rate and respiration monitoring method based on millimeter wave radar according to claim 2, characterized in that: The step of obtaining the standard distance between the driver and the transmitter to determine the standard distance range includes: Determine the standard distance between the driver and the transmitter for a preset time while the driver is speaking; The standard distance range is determined based on the standard distance.

4. The heart rate and respiration monitoring method based on millimeter wave radar according to claim 3 is characterized in that: Determining the standard distance range based on the standard distance includes: Performing statistical analysis on each of the standard distances to obtain an average value and a standard deviation of the standard distances; The difference and sum of the mean value and the standard deviation are calculated to determine the standard distance range.

5. The heart rate and respiration monitoring method based on millimeter wave radar according to claim 4, characterized in that: The determining the second duration based on the interval distance, the first duration and the standard distance range includes: Comparing the interval distance with the standard distance range, when the interval distance is not within the standard distance range during the monitoring time period reaching the first time period, stopping transmitting to the driver, and the second time period is the time from the transmission wave being transmitted to the stopping; During the time period when the monitoring duration reaches the first duration, if the interval distance is within the standard distance range, the second duration is equal to the first duration.

6. The heart rate and respiration monitoring method based on millimeter wave radar according to claim 5, characterized in that: The correcting the standard distance range to obtain a corrected distance range comprises: Determine the difference value between each of the standard distances, compare the difference value with a preset standard difference value, and perform corresponding standard distance screening based on the comparison result; If there is no abnormal difference value greater than the standard difference value in the difference values, the standard distance screening is to remove the suspicious distance corresponding to the maximum difference value in the difference values; If there is an abnormal difference value greater than the standard difference value in the difference values, the standard distance screening is to remove each abnormal distance corresponding to the abnormal difference value; Obtaining the corrected mean value and corrected standard deviation of each screening distance after standard distance screening; The difference and the sum of the corrected mean value and the corrected standard deviation are calculated to determine the corrected distance range.

7. The heart rate and respiration monitoring method based on millimeter wave radar according to claim 6, characterized in that: Determining the second heart rate and the second respiratory rate according to the second reflected wave signal comprises: Performing Fourier transform on the second reflected wave signal to obtain a second frequency domain signal; The second frequency domain signal is analyzed to determine the second heartbeat frequency and the second breathing frequency.

8. The heart rate and respiration monitoring method based on millimeter wave radar according to claim 7, characterized in that: The step of comparing the second heart rate and the second breathing rate with the corresponding standard heart rate range and standard breathing rate range to determine whether the driver is abnormal includes: If the second heart rate is within the standard heart rate range and the second breathing rate is within the standard breathing rate range, it is determined that the driver is normal; If either the second heart rate is not within the standard heart rate range or the second breathing rate is not within the standard breathing rate range, it is determined that the driver is abnormal.

9. The heart rate and respiration monitoring method based on millimeter wave radar according to claim 8, characterized in that: Determining whether the driver is speaking based on the mouth features includes: Determining a change factor of the mouth feature within a preset time; Comparing the change factor with a standard change threshold to obtain a comparison result; Based on the comparison result, it is determined whether the driver is speaking, wherein: If the change factor is less than the standard change threshold, it is determined that the driver is not speaking; If the change factor is greater than or equal to the standard change threshold, it is determined that the driver is speaking.

10. The heart rate and respiration monitoring method based on millimeter wave radar according to claim 9, characterized in that: The analyzing the first reflected wave signal to obtain a first heartbeat frequency and a first respiratory frequency comprises: Performing Fourier transform on the first reflected wave signal to obtain a first frequency domain signal; The first frequency domain signal is analyzed to determine the first heartbeat frequency and the first breathing frequency.

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