Earback heart rate and blood oxygen health monitoring method and system

Abstract

The invention discloses an ear back heart rate and blood oxygen health monitoring method and system, and the method comprises the steps: respectively obtaining photoelectric volume pulse wave signals of a left ear and a right ear in a preset time window, and carrying out the single-side availability judgment of each ear side; when the left ear and the right ear pass judgment, heart rate parameters and blood oxygen saturation parameters are calculated respectively, and difference values are compared; outputting a fusion result when the difference value is within a preset consistent range, and taking a result on the other side as effective output when the difference value exceeds the preset consistent range and the abnormal side meets a signal abnormal condition; and when only one side passes the judgment, outputting the result of the side, and when the two sides do not pass the judgment, marking as unavailable. According to the technical scheme, systematic physiological changes and unilateral local measurement anomalies can be distinguished by using symmetry and difference of left and right ear signals, and the reliability and stability of continuous monitoring of the heart rate and blood oxygen of the back of the ear are improved.

Description

Technical Field

[0001] This invention relates to the field of health monitoring technology for wearable products, and in particular to a method and system for monitoring heart rate and blood oxygenation behind the ear. Background Technology

[0002] Existing wearable earrings with health monitoring functions typically place optical sensors near the ear. They illuminate the superficial tissues of the ear with red and infrared light and receive reflected or transmitted light signals to obtain photoplethysmography (PPG) signals related to blood volume pulsation, and then calculate indicators such as heart rate and blood oxygen saturation. To balance aesthetics and wearing comfort, these devices often employ a design where the earring is on the front and the sensor and power module are on the back, placing the sensor close to the back of the ear or the surrounding area of ​​the auricle. This aims to obtain more stable blood flow signals than the wrist and enable long-term daily monitoring.

[0003] However, while the ear offers advantages in acquiring physiological signals, its measurement conditions are highly sensitive to local contact status and optical path environment during continuous monitoring. Everyday factors such as eyeglass temples, mask straps, hair obstructing the ear, and pressure from lying on one's side, coupled with potential slight positional shifts, tightness changes, or alterations in contact surface conditions during earring wear, can cause amplitude attenuation, baseline drift, or waveform distortion in the photoelectric signal from one ear even without significant movement. These changes further affect the stability of heart rate and blood oxygen calculations, making it difficult for the device to accurately distinguish whether abnormal changes originate from the subject's actual physiological state or measurement errors introduced by changes in local wearing conditions, thus leading to insufficient reliability of continuous monitoring results. Summary of the Invention

[0004] This application provides a method for monitoring heart rate and blood oxygen health behind the ear, aiming to solve the technical problem that existing earring-type health monitoring devices, during continuous monitoring behind the ear, have difficulty distinguishing between real physiological changes and measurement errors due to changes in unilateral local contact status or optical path environment, thus affecting the reliability of heart rate and blood oxygen monitoring results.

[0005] To achieve the above objectives, embodiments of this application provide a method for monitoring heart rate and blood oxygenation health behind the ear, comprising: Within a preset time window, photoplethysmography (PPG) signals from the left and right ears were acquired, and unilateral availability was determined for the left and right ears respectively. When both the left and right ears pass the unilateral availability determination, the heart rate parameters and blood oxygen saturation parameters of the left and right ears are calculated respectively, and the difference between the heart rate parameters and the difference between the blood oxygen saturation parameters of the left and right ears are compared. When the difference between the heart rate parameter and the difference between the blood oxygen saturation parameter are both within their respective preset ranges, the heart rate and blood oxygen monitoring results are output based on the left and right ears; When the difference in heart rate parameter or blood oxygen saturation parameter exceeds the corresponding preset consistency range, and the side with the difference exceeding the corresponding preset consistency range meets the preset signal abnormality condition, the heart rate and blood oxygen monitoring results of the other side are used as the valid output. When only one side passes the unilateral availability determination, the heart rate and blood oxygen monitoring results of the side that passed the determination are taken as the valid output; If neither the left nor the right ear passes the unilateral availability determination, the monitoring result of the current time window is marked as unavailable.

[0006] To achieve the above objectives, this application also proposes an ear-worn heart rate and blood oxygenation health monitoring system, including a left earring and a right earring; the left earring and the right earring are communicatively connected, and at least one of the left earring and the right earring includes a memory and at least one processor, the memory storing instructions; the memory and the at least one processor are interconnected via a circuit; the at least one processor calls the instructions in the memory to cause the ear-worn heart rate and blood oxygenation health monitoring system to perform the steps of the above-described ear-worn heart rate and blood oxygenation health monitoring method.

[0007] To achieve the above objectives, this application also proposes a storage medium storing instructions that, when run on a computer, cause the computer to execute the steps of the above-described ear-tie heart rate and blood oxygen health monitoring method.

[0008] The technical solution provided in this application acquires photoplethysmography (PPG) signals from the left and right ears respectively within a preset time window, and performs a unilateral availability determination for each ear side, ensuring that the signals entering subsequent calculations first meet basic measurability conditions. Optical measurements at the back of the ear are highly sensitive to changes in local contact and the optical path environment. When one side is obstructed, compressed, or slightly displaced, the PPG wave may still exhibit periodic fluctuations, but its amplitude, baseline, or waveform morphology often deviates from a state suitable for blood oxygen and heart rate calculations. Placing the availability determination before parameter calculation is equivalent to setting a threshold on the data link, preventing the direct conversion of distorted signals caused by changes in local conditions into heart rate and blood oxygen results, thereby reducing abnormal outputs triggered by non-physiological factors and providing a prerequisite for subsequent interpretation of differences between the left and right ears.

[0009] When both ears pass the unilateral availability assessment, heart rate and blood oxygen saturation parameters are calculated separately for each ear, and the differences are compared. The characteristic that both ears reflect the same circulatory and oxygenation status of the body within the same time period is used for comparative judgment. Systemic physiological changes usually manifest as changes in the same direction or with similar amplitudes on both sides. Therefore, when the difference in parameters between the two sides remains within a preset consistent range, it indicates that the measured change is more likely to come from the subject's true physiological fluctuations rather than local measurement bias. If the difference in heart rate or blood oxygen exceeds the consistent range, it means that there is an asymmetrical change between the two sides. In behind-the-ear scenarios, asymmetrical changes are more commonly caused by local factors such as pressure from the temple of glasses, hair obstruction, or pressure from lying on one side, causing the signal on that side to drift or attenuate. To avoid misjudging such unilateral deviations as systemic abnormalities, a constraint is introduced that the abnormal side meets preset signal abnormality conditions. This ensures that asymmetrical differences are only classified as local measurement abnormalities when accompanied by typical signs of signal abnormality. In this case, the calculation result of the other side is used as the valid output, thereby suppressing local errors. For cases where only one side passes the unilateral availability check, the monitoring result of the side that passed the check is directly output, allowing continuous monitoring to be maintained even when local interference occurs. When neither side passes the check, the result is marked as unusable, thus avoiding potentially misleading values ​​given in the absence of reliable input. Through this process, the most difficult-to-handle unilateral local condition changes in continuous behind-the-ear monitoring are transformed into identifiable and isolable states, thereby improving the reliability and stability of heart rate and blood oxygenation monitoring results. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of one embodiment of the ear-back heart rate and blood oxygen health monitoring method of the present invention.

[0012] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0013] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0014] One embodiment of this application provides a method for monitoring heart rate and blood oxygenation health behind the ear. Figure 1 This is a flowchart illustrating a method for monitoring heart rate and blood oxygenation via the ear, provided in one embodiment of this application. In this embodiment, the method includes: Please see Figure 1 Within a preset time window, photoplethysmography (PPG) signals from the left and right ears are acquired respectively, and unilateral availability is determined for the left and right ears respectively. Specifically, the earrings used for behind-the-ear heart rate and blood oxygen monitoring include a left earring and a right earring. Both have essentially the same structure, consisting of a front earpiece and a rear ear sensing module, which is fitted against the skin behind the ear. The rear ear sensing module contains a rechargeable battery, a power management circuit, a main control chip, a light-emitting unit, and a photoelectric receiving unit. The light-emitting unit includes at least two light-emitting devices of different wavelengths, such as a red LED and an infrared LED, arranged side-by-side or in a ring at an optical window facing the skin. The photoelectric receiving unit is a photodiode or photosensitive sensor arranged adjacent to the light-emitting unit, used to receive light signals reflected by the tissue behind the ear. The battery is a built-in rechargeable battery, which powers the main control chip, light-emitting unit, and receiving unit through the power management circuit. The main control chip periodically drives the light-emitting devices of different wavelengths to emit light alternately in a pulsed manner according to a preset program, and synchronously controls the receiving unit to sample during the corresponding light emission periods.

[0015] When the user wears the left and right earrings behind both ears, the sensor module behind the ear is in close contact with the skin behind the ear. The light emitted by the light-emitting unit enters the superficial tissue behind the ear. The blood volume in the tissue changes with the heartbeat cycle, causing periodic changes in the absorption of different wavelengths of light. The reflected light intensity changes are converted into current signals by the photoelectric receiving unit. After being amplified and filtered by the analog front-end circuit, the signals are sent to the analog-to-digital converter module inside the main control chip to form a continuous digital photoplethysmography (PPG) signal. The left and right earrings independently complete the above acquisition process, and each segment of acquired data is marked with a time stamp in its respective main control chip. To ensure the comparability of the data from both sides, the left and right earrings synchronize their time through short-range wireless communication when entering monitoring mode. For example, one side sends a time reference signal as the master side, and the other side calibrates its internal timing accordingly. This allows for the division of preset time windows according to a unified time rhythm during subsequent operation, such as a window every few seconds. Each earring continuously collects and caches corresponding waveform data within each time window, and sends the time-stamped window data to the main processing unit or one of the earrings via a wireless link for aggregation. This allows the photoplethysmography (PPG) signals corresponding to the left and right ears to be obtained simultaneously within the same time period, providing a synchronous data foundation for subsequent parameter calculations and cross-ear comparisons.

[0016] In one embodiment of the present invention, the step of acquiring photoplethysmography (PPG) signals from the left and right ears respectively, and performing unilateral availability determination for the left and right ears respectively, includes: At least two different wavelengths of photoplethysmography signals were acquired from the left and right ears, respectively. The DC and AC components of each wavelength channel on each ear side are extracted separately, and the AC-DC ratio of each wavelength channel is calculated. When the AC / DC ratio of each wavelength channel on the same ear side meets the preset amplitude availability condition, it is determined that the ear side meets the amplitude availability condition.

[0017] When the amplitude is available on each ear side, the consistency of pulsation characteristics of photoplethysmography (PPG) signals of different wavelengths is determined. The consistency of pulsation characteristics is determined by judging whether the pulse period of different wavelength signals on the same ear side is consistent within the preset time window, and whether the occurrence sequence of peaks and troughs of each wavelength channel is consistent. When the pulse period is consistent and the occurrence sequence is consistent, it is determined that the ear side meets the consistency of pulsation characteristics. When the same ear side simultaneously meets the amplitude availability condition and the pulsation feature consistency determination, the ear side is determined to pass the unilateral availability determination; otherwise, the ear side is determined not to pass the unilateral availability determination.

[0018] Specifically, when acquiring at least two different wavelengths of photoplethysmography (PPG) signals within a preset time window, the left and right earrings are worn on the left and right ears respectively. The optical window of the ear-back sensing module fits against the skin behind the ear and is powered by a built-in rechargeable battery. The main control chip drives the two wavelength light-emitting devices to emit light alternately and sample synchronously according to a preset timing sequence. The two wavelengths can be specifically selected as red light with a center wavelength of approximately 660nm and infrared light with a center wavelength of approximately 940nm. Both LEDs are set on the side facing the skin and arranged adjacent to the photodetector, so that the incident light enters the superficial tissue behind the ear and is absorbed by the blood and tissue, producing reflection. Since the heartbeat causes the blood volume in the superficial blood vessels behind the ear to increase or decrease periodically, the absorption of light by the blood changes periodically accordingly, and the intensity of the reflected light also fluctuates with the heartbeat rhythm. The photodetector converts this intensity change into an electrical signal, which is amplified by the analog front end and filtered for anti-aliasing before being digitized by the analog-to-digital converter to obtain a time-varying PPG sequence. To avoid crosstalk between the two wavelengths, a time-division multiplexing method can be used. For example, within every 1ms period, the 660nm LED is turned on first and sampled once after it stabilizes, then the 940nm LED is turned on and sampled once, while the light emission is turned off during the remaining periods. In this way, digital PPG sequences for the red and infrared channels can be formed separately within a 5-second window. The left and right earrings can each independently generate time-stamped window data, and the start and end of the window are ensured to be consistent after time synchronization, so that the data from the left and right earrings within the same window can be used for subsequent comparison.

[0019] When extracting the DC and AC components for each wavelength channel on each ear side, the PPG signal needs to be decomposed into a background component and a pulsation component. The DC component represents the background light intensity level within the window, which can be characterized by the average value of the sampled values ​​within the window. It shifts upward or downward depending on local conditions such as tightness of the fit, occlusion, contamination, and pressure. For example, side-lying pressure or hair occlusion may weaken the overall reflected light, causing the average value to drift. The AC component represents the periodic fluctuation amplitude caused by the heartbeat. The pulsation amplitude can be calculated after removing the DC component, for example, by using the peak-to-peak value or root mean square value of the remaining waveform. When local pressure leads to a decrease in vascular perfusion, the pulsation amplitude usually decreases, i.e., the AC component decreases. The AC-DC ratio is obtained by dividing the AC component by the DC component. It is used to normalize and compare the pulsation intensity under different individual skin thicknesses, light intensities, and receiver gains. For example, the ratio is 0.02 when the DC is 1.2V and the AC peak-to-peak value is 0.024V. The preset amplitude availability condition can be set to an AC / DC ratio within a reasonable range, such as between 0.005 and 0.05. A value below 0.005 often indicates weak pulsation or pressure attenuation, leading to unstable blood oxygen and heart rate calculations. A value above 0.05 is commonly seen in non-physiological fluctuations introduced by strong noise, abnormal reflections in the optical path, or unstable contact. Only when both wavelength channels on the same ear side meet this range are they considered to have sufficient and not excessively abnormal pulsation information within the window, thus meeting the amplitude availability condition. The significance of this is that by ensuring both wavelengths meet the standard simultaneously, occasional anomalies in a single channel can be eliminated, avoiding the mistaken identification of local interference signals as usable signals based solely on the amplitude of a single channel.

[0020] After the amplitude availability condition is met, the consistency of pulse characteristics is determined to confirm that the two wavelengths are indeed reflecting the blood volume change caused by the same heartbeat, rather than being skewed by local disturbances. This is achieved by detecting the pulse cycle and peak-to-trough timing of the red and infrared channels separately within the same time window and determining whether they are consistent. The pulse cycle can be obtained by finding the local maximum value in the waveform after DC removal as the peak, calculating the time interval between adjacent peaks, and averaging them; for example, if 6 to 8 peaks are detected within a 5-second window, the average cycle may be between 0.6 and 1.0 seconds. Cycle consistency can be represented by a difference threshold; for example, if the difference in the average cycle between the two channels does not exceed 0.05 seconds, they are considered consistent. This magnitude is much smaller than a heartbeat cycle, tolerating slight noise and sampling jitter while being sufficient to identify significant asynchrony. Peak-trough temporal consistency can be achieved by pairing the peak times of two channels within the same heartbeat and calculating the time difference. For example, it is required that the time difference of most paired peaks does not exceed 10 to 20 milliseconds. This is because the two channels originate from the same site and the same blood volume event, and their main peaks should be almost synchronous. If a larger and sustained misalignment occurs, it usually means that the waveform on one side is disturbed by local motion, optical path obstruction, or contact slippage, resulting in the detected peak not being the true pulse peak. Only when the period is consistent and the peak-trough temporal consistency is consistent can the ear side be determined to meet the pulsation characteristic consistency criterion.

[0021] When the same ear side simultaneously meets both the amplitude availability condition and the pulsation characteristic consistency criterion, it indicates that the ear side has sufficient pulsation amplitude within the window and exhibits a consistent physiological rhythm across different wavelengths. This eliminates many false fluctuations or drifts caused by factors such as local obstruction, pressure, loosening, or contamination, thus allowing the ear side to pass the unilateral availability criterion. Conversely, if either condition is not met, the signal within the window is considered likely to be primarily affected by local measurement conditions and unsuitable for subsequent heart rate and blood oxygenation calculations. This avoids misinterpreting changes in local conditions as changes in the subject's true physiological state, providing a reliable input basis for subsequent cross-ear comparisons and effective output selection.

[0022] Please continue reading. Figure 1 When both the left and right ears pass the unilateral availability determination, the heart rate parameters and blood oxygen saturation parameters of the left and right ears are calculated respectively, and the difference between the heart rate parameters and the difference between the blood oxygen saturation parameters of the left and right ears are compared. Within each ear's time window, peak detection is performed on the pulse waveform after removing the DC component. Valid heartbeat peaks are identified by finding peaks with local maximum values ​​and minimum intervals of approximately 0.3 seconds or more, thus avoiding misinterpreting noise or secondary waveforms as heartbeats. The time intervals between adjacent valid peaks are recorded. For example, if 7 valid peaks are detected within a 5-second window, 6 adjacent intervals are obtained, and the average of these intervals is calculated as the average heartbeat cycle within that window. Heart rate parameters can be expressed as the number of heartbeats per minute, calculated by dividing 60 by the average cycle. For example, with an average cycle of 0.8 seconds, the heart rate is 75 beats per minute. By statistically analyzing multiple heartbeat cycles within a window and averaging them, the influence of individual abnormal peaks on the results can be reduced, making the heart rate parameters more stable. The heart rate parameters for both ears are calculated independently using the same method.

[0023] The calculation of blood oxygen saturation parameters is based on the proportional relationship between the AC / DC ratio of red light and infrared wavelengths. For each ear, the AC / DC ratio of the red light channel and the infrared channel is calculated separately within the current time window, denoted as Rred and Rinfrared. Then, the ratio R is calculated, i.e., R = Rred / Rinfrared. This R value reflects the relative change in absorption due to differences in blood at different wavelengths and corresponds to blood oxygen saturation. The device can be calibrated at the factory using a standard pulse oximeter to establish a curve corresponding to the R value and blood oxygen saturation. During operation, the R value can be converted to blood oxygen saturation parameters through table lookup or a simple linear approximation. For example, when the R value is around 1.0, blood oxygen saturation may be around 98%, and when the R value increases to 1.2, blood oxygen saturation may decrease to around 92%. The corresponding blood oxygen saturation parameters are calculated for each ear based on its respective R value.

[0024] After obtaining the heart rate and blood oxygen saturation parameters for the left and right ears, the differences between the two sides are calculated. The heart rate difference can be expressed as the absolute difference between the two sides; for example, if the left ear is 75 beats per minute and the right ear is 77 beats per minute, the difference is 2 beats per minute. The blood oxygen difference can be expressed as the absolute difference between the two sides' blood oxygen saturation; for example, if the left ear is 97% and the right ear is 96%, the difference is 1%. To determine if the two sides are consistent, a preset consistency range can be set, such as a heart rate difference not exceeding 5 beats per minute and a blood oxygen difference not exceeding 2 percentage points. This range is set because the left and right ears are located in the same circulatory system, and under normal physiological conditions, the heart rhythm and blood oxygenation status reflected by both sides should be basically consistent. Normal physiological fluctuations should not produce significant differences between the two sides. When the calculated difference is within this consistency range, the parameters of both sides can be considered mutually corroborating. If the difference significantly exceeds this range, it suggests a possible unilateral local measurement abnormality or a very rare physiological asymmetry, requiring further judgment based on subsequent abnormal conditions. Through the above calculation and comparison steps, a consistent assessment of the monitoring results of the left and right ears is achieved, providing a quantitative basis for distinguishing between systemic physiological changes and unilateral local interference.

[0025] Please continue reading. Figure 1 When the difference between the heart rate parameter and the difference between the blood oxygen saturation parameter are both within their respective preset ranges, the heart rate and blood oxygen monitoring results are output based on the left and right ears. In one embodiment of the present invention, the step of monitoring heart rate and blood oxygenation based on the output results of the left and right ears includes: The fusion weights are determined based on the AC / DC ratios of the left and right ears, and the heart rate and blood oxygen saturation parameters of the left and right ears are weighted and fused before output; or, The AC / DC ratio of the left and right ears is compared, and the heart rate and blood oxygen saturation parameters of the side with the higher AC / DC ratio are used as the output results.

[0026] Specifically, the AC / DC ratio is not only used to determine signal usability, but also serves as a quantitative indicator of signal strength and stability. Within the same time window, if the AC / DC ratio of the left ear infrared channel is 0.025 and that of the right ear is 0.015, it indicates that the pulsation component of the left ear is more pronounced relative to the background light intensity within the current window, resulting in a higher effective signal amplitude and stronger noise immunity. Therefore, the AC / DC ratio can be used as the basis for fusion weights.

[0027] In practice, the AC / DC ratio of the left and right ears can be normalized first. For example, let the AC / DC ratio of the left ear be R. L The right ear is R R Then the weight of the left ear can be defined as R. L / (R L +R R The right ear has a weight of R.R / (R L +R R ). With R L =0.025, R R Taking a value of 0.015 as an example, the weight of the left ear is approximately 0.625, and the weight of the right ear is approximately 0.375. The heart rate parameters of the left and right ears are then multiplied by their respective weights and summed to obtain the fused heart rate parameters. Similarly, the blood oxygen saturation parameters are weighted and summed to obtain the fused blood oxygen result. Since the weights are proportional to the AC / DC ratio, the side with higher signal quality has a larger proportion in the fused result, while the side with lower signal quality retains some reference value, thus improving output stability while ensuring continuity.

[0028] Another approach is to avoid weighted calculations and directly compare the AC / DC ratios of the left and right ears. The side with the higher ratio is considered the more reliable signal within the current window, and its heart rate and blood oxygen saturation parameters are directly output. For example, if the AC / DC ratio of the left ear is 0.028 and that of the right ear is 0.010, it indicates that there may be slight poor contact or local compression in the right ear causing weakened pulsation. In this case, directly using the calculation result from the left ear as the output avoids interference from low-quality signals. This method requires less computation and is suitable for resource-constrained embedded systems.

[0029] Both of the above methods are based on the characteristic that the AC-DC ratio reflects signal quality. Under the premise that the parameters of the left and right ears are basically the same, the output strategy is adjusted by the quality difference, so that the output result is closer to the real physiological information of the side with better signal quality, thereby further improving the stability and reliability of heart rate and blood oxygen monitoring results.

[0030] Please continue reading. Figure 1 When the difference in heart rate parameter or blood oxygen saturation parameter exceeds the corresponding preset consistency range, and the side with the difference exceeding the corresponding preset consistency range meets the preset signal abnormality condition, the heart rate and blood oxygen monitoring results of the other side are used as the valid output. In one embodiment of the present invention, the preset signal abnormality condition includes: If the difference exceeds the corresponding preset consistency range on one side, the DC component of its photoplethysmography signal drifts beyond the preset range relative to the previous time window or multiple consecutive time windows, or the AC-DC ratio on that ear side is lower than the preset lower threshold.

[0031] Specifically, during continuous monitoring, the DC component of the current time window can be compared with the DC component of the previous time window, or with the average value of several consecutive windows. For example, if the DC component of the left ear is stable between 1.10 V and 1.15 V in the previous few windows, but suddenly rises to 1.35 V or falls to 0.90 V in the current window, and the change exceeds the preset range, such as ±10% or ±0.15 V, then the optical path or contact state on that side can be considered to have changed significantly. Such changes usually correspond to situations such as the back of the ear being pressed, loosened, obstructed by hair, or local contamination of the sensing window, and are unlikely to be caused by short-term changes in systemic blood oxygen or heart rate, because systemic physiological changes would not cause such a sudden change in the background intensity of reflected light. Therefore, when abnormal drift of the DC component occurs on the side where the difference exceeds the uniform range, that side can be identified as having a local measurement anomaly.

[0032] Another method of determination is to check whether the AC / DC ratio on that side is lower than a preset lower threshold. The AC / DC ratio represents the proportion of pulsation amplitude to background light intensity. When local pressure behind the ear leads to reduced vascular perfusion or poor sensor contact, the pulsation amplitude usually decreases significantly, while the DC component may not change much, thus causing the ratio to decrease significantly. For example, if the AC / DC ratio is 0.02 under normal conditions, but drops to 0.003 after pressure, which is lower than the set lower limit of 0.005, it indicates that the pulsation signal on that side is too weak to reliably reflect the true changes in blood volume. In this case, even if the calculated blood oxygen or heart rate shows a significant deviation, it is more likely due to the deterioration of local measurement conditions rather than true physiological changes.

[0033] Using the two judgment methods mentioned above, as long as the difference exceeds the uniform range on one side, and simultaneously satisfies either abnormal drift of the DC component or the AC-DC ratio being lower than the lower limit threshold, it can be considered that there is a local measurement abnormality on that side within the current window. This provides a basis for selecting the output of the other side, avoiding mistaking data from a single side that is interfered with as a systemic physiological abnormality.

[0034] Please continue reading. Figure 1 When only one side passes the unilateral availability determination, the heart rate and blood oxygen monitoring results of the side that passed the determination are taken as the valid output; If neither the left nor the right ear passes the unilateral availability determination, the monitoring result of the current time window is marked as unavailable.

[0035] Specifically, when only one side passes the single-sided availability determination, it indicates that within the current time window, the signal from the other ear does not meet the usability standard due to localized pressure, obstruction, or abnormal contact, while the side that passed the determination can still provide a pulse wave signal with sufficient amplitude and consistent rhythm. In this case, the heart rate and blood oxygen saturation parameters calculated from the determined side within this time window can be directly used as valid output values, and a status identifier can be added to this output, such as marked as "single-sided output" or "degraded mode". The processing unit encapsulates the output data of this window into a data frame containing a timestamp, heart rate value, blood oxygen value, and status identifier, and sends it to the smart terminal paired with the earring, such as a mobile phone, tablet, or smartwatch, via a low-power wireless communication module. After receiving the data, the application in the terminal parses it and displays the current heart rate and blood oxygen values ​​on the interface. It can also indicate the current single-sided validity status with an icon or text next to the values ​​so that the user understands the data source and reliability. When multiple consecutive windows are single-sided outputs, the application can also record the duration of this status for subsequent health trend analysis.

[0036] When neither the left nor the right ear passes the unilateral availability determination, it indicates a significant anomaly in the signals from both sides within the current time window, such as an excessively low AC / DC ratio or disordered pulsation rhythm, making it impossible to guarantee the reliability of the calculation results. In this case, the processing unit does not output specific heart rate and blood oxygen values, but instead marks the monitoring results for that time window as unavailable and sends a data frame containing a timestamp and an unavailable flag to the smart terminal via wireless communication. Upon receiving the unavailable flag, the application can display the current data as unavailable on the interface using a gray value, a null value, or a specific icon, and can determine whether to issue a reminder to the user based on a preset strategy. For example, when multiple consecutive time windows are in an unavailable state, the application can pop up a prompt message suggesting that the user check the wearing position, adjust the earring fit, or clean the sensor window. Through the above data encapsulation, wireless transmission, and terminal application linkage mechanism, a complete output process is achieved from behind-the-ear signal acquisition to user visualization and status reminders, enabling users to understand the current monitoring results and their reliability in real time.

[0037] In one embodiment of the present invention, when one side fails the single-sided availability determination, a self-test sequence is performed on that side. The self-test sequence includes adjusting the luminous intensity or receiving gain of that side at least once, and after adjustment, re-determining whether the DC component of that side has recovered to a preset available range and whether the AC-DC ratio has recovered to above a preset available threshold. If recovered, the abnormality mark of that side is removed and it is re-included in the cross-ear control. If not recovered, that side is isolated from the output link, and only the heart rate and blood oxygen monitoring results of the other side are continuously output.

[0038] It should be noted that the self-test sequence can be initiated at the start of the next time window, during which the main control chip adjusts the luminous intensity or receiving gain on that side at least once. For example, under normal sampling conditions, the red and infrared luminous currents are set to 5 mA, and the receiving gain is a fixed amplification factor. In the self-test sequence, the luminous current can be increased to 8 mA or decreased to 3 mA, and the receiving amplification factor can be adjusted simultaneously, allowing the system to re-acquire data for a short time window under different light intensities or sensitivity conditions. By changing the luminous intensity or receiving gain, it can be determined whether the original anomaly was caused by optical path attenuation, loose contact, or partial obstruction. This is because if the signal weakening is due to insufficient light intensity or slight contact misalignment, the DC and AC components will usually return to a reasonable range after increasing the luminous intensity or gain.

[0039] After completing the adjusted acquisition, the DC component to AC DC ratio of the signal on that side is calculated again, and it is determined whether it has returned to the preset usable range. For example, if the original AC DC ratio is below 0.005, and it recovers to above 0.015 after increasing the light intensity, and the DC component does not show abnormal drift, then the signal on that side can be considered to have returned to normal, and the previous abnormality was a temporary interference. At this time, the abnormality mark on that side is removed, and it is reintroduced into the left and right ear cross-ear comparison process to restore bilateral participation in the output.

[0040] If, after completing one or a preset number of self-test adjustments, the DC component on that side continues to drift beyond a reasonable range, or the AC-DC ratio remains below the lower threshold, the anomaly is not simply due to insufficient light intensity, but more likely to be caused by continuous pressure, severe obstruction, or structural contact issues. In this case, that side is isolated from the current output link and no longer participates in heart rate and blood oxygen fusion or comparison. Only the other side continues to output monitoring data based on the availability determination of a single side. Simultaneously, the system can record that the isolated side is in an isolated state and attempt self-tests again at preset intervals, so that it can automatically resume operation once wearing conditions improve. This process of attempting recovery first and then deciding on isolation avoids unnecessary downtime caused by transient interference and ensures the reliability of output results when the signal is continuously abnormal.

[0041] In one embodiment of the present invention, after the ear side is isolated, the self-test sequence is continuously executed on the ear side at preset intervals; if the ear side recovers in the self-test sequence, the isolation is lifted and the ear side is re-included in the cross-ear control; if the other ear side also fails the unilateral availability determination during the isolation period, a prompt is issued to the user.

[0042] Specifically, when one ear is isolated from the output link due to continuous abnormalities, it does not mean that the ear has permanently failed, but rather that it enters a recovery state. In this state, the system still maintains periodic monitoring of that ear, but no longer uses it in the calculation of current heart rate and blood oxygenation results. In practice, a preset interval period can be set, such as executing a self-test sequence every 30 seconds or every minute. Within this self-test window, the main control chip re-acquires multi-wavelength photoplethysmography (PPG) signals for a short period of time according to preset drive parameters, and calculates the DC component to AC-DC ratio according to the aforementioned process, while simultaneously determining the consistency of pulsation characteristics. If, within this self-test window, the DC component recovers to a stable range, the AC-DC ratio is higher than the lower threshold, and the rhythms of the two wavelengths are consistent, it indicates that the original abnormality may have been caused by short-term pressure or wearing misalignment and has been eliminated. At this time, the isolation state of that ear is released, and it is reintegrated into the left-right ear cross-ear comparison process, allowing both ears to participate in subsequent output.

[0043] If one side fails to meet the single-sided availability requirement after multiple self-tests, it remains isolated to prevent its abnormal signals from affecting the overall output. Simultaneously, the availability of the other side is continuously monitored during isolation. If the other side also fails the single-sided availability requirement within a certain time window, it indicates that both sides are currently in an abnormal state, such as both ears being covered or the earrings being noticeably loose. In this case, the system no longer outputs specific heart rate and blood oxygen values, but instead sends the current status to the paired terminal via wireless communication. The terminal application can display a data unavailability message on the interface and pop up a reminder message, suggesting the user adjust the wearing position or check the earring fit. Through this periodic self-test and status linkage mechanism, the system can maintain continuous monitoring while achieving automatic recovery and necessary reminders, reducing accidental shutdowns and avoiding the output of unreliable data when both sides are abnormal.

[0044] In another embodiment of this application, a back-of-ear (BTE) heart rate and oxygenation health monitoring system is proposed. This system can vary significantly due to differences in configuration or performance, and may include one or more processors (e.g., one or more processors) and memory, and one or more storage media for storing applications or data. The memory and storage media can be temporary or persistent storage. The program stored in the storage media may include one or more modules, each module including a series of instruction operations on the BTE heart rate and oxygenation health monitoring system. Furthermore, the processor may be configured to communicate with the storage media and execute the series of instruction operations in the storage media on the BTE heart rate and oxygenation health monitoring system to implement the steps of the aforementioned BTE heart rate and oxygenation health monitoring method.

[0045] The present invention also provides a storage medium, which can be a non-volatile storage medium or a volatile storage medium, wherein the storage medium stores instructions that, when executed on a computer, cause the computer to perform the steps of the ear-back heart rate and blood oxygen health monitoring method.

[0046] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A behind-the-ear heart rate blood oxygen health monitoring method, characterized in that, The method comprises the following steps: acquiring photoelectric plethysmogram signals of left and right ears respectively within a preset time window, and performing unilateral availability determination on the left and right ears respectively; when the left and right ears both pass the unilateral availability determination, calculating heart rate parameters and blood oxygen saturation parameters of the left and right ears respectively, and comparing the difference of the heart rate parameters and the difference of the blood oxygen saturation parameters of the left and right ears; when the difference of the heart rate parameters and the difference of the blood oxygen saturation parameters are both within respective preset consistent ranges, outputting heart rate and blood oxygen monitoring results based on the left and right ears; when the difference of the heart rate parameters or the difference of the blood oxygen saturation parameters exceeds the corresponding preset consistent range, and the side of the difference exceeding the corresponding preset consistent range meets a preset signal abnormality condition, taking the heart rate and blood oxygen monitoring result of the other side as the effective output; when only one side passes the unilateral availability determination, taking the heart rate and blood oxygen monitoring result of the determined side as the effective output; when the left and right ears both fail to pass the unilateral availability determination, marking the monitoring result of the current time window as unavailable.

2. The ear back heart rate blood oxygen health monitoring method of claim 1, wherein, The method of acquiring photoelectric plethysmogram signals of left and right ears respectively and performing unilateral availability determination on the left and right ears respectively comprises the following steps: acquiring photoelectric plethysmogram signals of at least two different wavelengths of the left and right ears respectively; extracting direct current components and alternating current components of each wavelength channel of each ear side, and calculating alternating current to direct current ratios of each wavelength channel; when the alternating current to direct current ratios of each wavelength channel of the same ear side all meet a preset amplitude available condition, determining that the ear side meets the amplitude available condition.

3. The ear back heart rate blood oxygen health monitoring method of claim 2, wherein, When the amplitude available condition is met at each ear side, performing pulsation feature consistency determination on the photoelectric plethysmogram signals of different wavelengths; wherein, the pulsation feature consistency determination comprises judging whether the pulse periods of the photoelectric plethysmogram signals of different wavelengths of the same ear side within the preset time window are consistent, and whether the occurrence timing of the wave peaks and wave troughs of each wavelength channel is consistent, when the pulse periods are consistent and the occurrence timing is consistent, determining that the ear side meets the pulsation feature consistency determination; when the same ear side meets both the amplitude available condition and the pulsation feature consistency determination, determining that the ear side passes the unilateral availability determination, otherwise, determining that the ear side fails to pass the unilateral availability determination.

4. The ear back heart rate blood oxygen health monitoring method of claim 1, wherein, The preset signal abnormality condition comprises: on the side of the difference exceeding the corresponding preset consistent range, the direct current component of the photoelectric plethysmogram signal of the ear side drifts beyond a preset change range relative to the previous time window or multiple continuous time windows, or the alternating current to direct current ratio of the ear side is lower than a preset lower threshold.

5. The ear back heart rate blood oxygen health monitoring method of claim 1, wherein, The method of outputting heart rate and blood oxygen monitoring results based on the left and right ears comprises the following steps: determining corresponding fusion weights according to the alternating current to direct current ratios of the left and right ears respectively, and outputting the heart rate parameters and blood oxygen saturation parameters of the left and right ears after weighted fusion; or comparing the alternating current to direct current ratios of the left and right ears, and taking the heart rate parameters and blood oxygen saturation parameters of the ear side with higher alternating current to direct current ratio as the output result.

6. The behind-the-ear heart rate blood oxygen health monitoring method of claim 1, wherein, When one side fails the single-side availability determination, a self-check sequence is performed on the side, the self-check sequence comprising at least one adjustment to the light emission intensity or receiving gain of the side, and after the adjustment, re-determining whether the DC component of the side is restored to within the preset available range and the AC / DC ratio is restored to above the preset available threshold; If restored, the abnormal flag of the side is removed and the side is re-included in the cross-ear comparison; if not restored, the side is isolated from the output link and only the heart rate and blood oxygen monitoring results of the other side are continuously output.

7. The ear back heart rate blood oxygen health monitoring method of claim 6, wherein, After the ear side is isolated, the self-check sequence is continuously performed on the side at a preset interval period; if the side is restored in the self-check sequence, the isolation is removed and the side is re-included in the cross-ear comparison; If the other side also fails the single-side availability determination during the isolation, a prompt is issued to the user.

8. An ear behind the heart rate blood oxygen health monitoring system, characterized in that, The ear back heart rate and blood oxygen health monitoring method comprises a left ear ring and a right ear ring; the left ear ring and the right ear ring are communicatively connected; at least one of the left ear ring and the right ear ring comprises a memory and at least one processor; the memory stores instructions; the memory and the at least one processor are interconnected by a circuit; the at least one processor invokes the instructions in the memory to perform the steps of the ear back heart rate and blood oxygen health monitoring method according to any one of claims 1 to 7.

9. A storage medium having stored thereon instructions, the instructions comprising: The instructions are executed by the processor to implement the steps of the ear back heart rate and blood oxygen health monitoring method according to any one of claims 1 to 7.

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