Smart ring-based ppg signal enhancement method, device and storage medium

Abstract

The application discloses a PPG signal enhancement method and device based on a smart ring and a storage medium, and is used for improving the collection intensity of a PPG signal of the smart ring. The method comprises the following steps: acquiring an LED-PD horizontal interval on a PCB, wherein the LED-PD horizontal interval is the distance between an LED module and a PD module on the PCB; after the PCB is installed on the smart ring, generating a curvature tilt angle according to size data of the smart ring and the LED-PD horizontal interval, wherein the curvature tilt angle is a natural tilt angle caused by the curvature formed by the LED module and the PD module; generating an emission tilt angle and a collection tilt angle for the LED module and the PD module respectively according to the curvature tilt angle; and performing tilt processing on the LED module and the PD module respectively according to the emission tilt angle and the collection tilt angle.

Description

Technical Field

[0001] This application relates to the field of smart rings, and more particularly to a PPG signal enhancement method, apparatus, and storage medium based on a smart ring. Background Technology

[0002] With the continuous maturation of vital sign detection technology, the analysis of human condition using vital signs collected by various devices is becoming increasingly sophisticated. Heart rate monitoring is currently one of the most important vital sign monitoring indicators, and signal collection is typically achieved by wearing a smart monitoring bracelet on the wrist or a smart monitoring ring on the finger. Smart rings, with their advantages of small size, low contact loss rate, non-intrusive monitoring, and resistance to impacts, coupled with the rich blood vessels in the fingertips, are gradually being widely used in daily vital sign monitoring.

[0003] Current smart ring PPG signal sensors primarily use LED and PD modules. These modules are typically mounted parallel to each other on a PCB board, with both the light emission and reception directions perpendicular to the finger's skin surface. This parallel arrangement presents several problems. First, when the LED module emits light perpendicular to the skin surface, most of the light energy is concentrated in the superficial layers (epidermis and dermis, 0-1mm deep), resulting in insufficient light energy reaching the finger's arterial layer (1.5-3mm deep). This leads to a weak AC component from arterial pulsation in the PPG signal, resulting in insufficient optical path depth. Second, when the PD module receives light perpendicular to the skin, it mainly collects light scattered from the superficial layers, resulting in low efficiency in collecting deep arterial pulsation signals; in other words, the PD module has low reception efficiency. To solve the above problems, the acquisition angle of the LED module and PD module can be adjusted. However, the conventional adjustment method also has problems. The inner ring of the smart ring is fitted to the curved surface of the finger. This means that the parallel installation of the LED module and PD module and the adjustment of the acquisition angle do not take into account the cylindrical geometric features of the finger. That is, the PPG signal detection optical path does not take into account the influence of the finger curvature, which leads to the insufficient acquisition intensity of the PPG signal of the smart ring. Summary of the Invention

[0004] This application discloses a PPG signal enhancement method, apparatus, and storage medium based on a smart ring, used to improve the acquisition strength of the PPG signal from the smart ring.

[0005] In a first aspect, this application provides a PPG signal enhancement method based on a smart ring, comprising: Obtain the horizontal spacing between LEDs and PDs on the PCB board. The horizontal spacing between LEDs and PDs is the distance between the LED modules and PD modules on the PCB board. After the PCB board is installed on the smart ring, the curvature tilt angle is generated based on the size data of the smart ring and the horizontal spacing between the LED and PD modules. The curvature tilt angle is the natural tilt angle caused by the curvature formed by the LED module and the PD module. Based on the curvature tilt angle, emission tilt angle and acquisition tilt angle are generated for the LED module and PD module, respectively; The LED module and PD module are tilted according to the emission tilt angle and the acquisition tilt angle, respectively.

[0006] Optionally, the steps of tilting the LED module and the PD module according to the emission tilt angle and the acquisition tilt angle respectively specifically include: The LED module is tilted according to the emission tilt angle so that the main light-emitting axis of the LED module is deflected from the direction perpendicular to the skin to the direction away from the PD module; The PD module is tilted according to the acquisition tilt angle so that the receiving main axis of the PD module is deflected from the direction perpendicular to the skin to the direction closer to the LED module.

[0007] Optionally, after the step of tilting the LED module and PD module according to the transmission tilt angle and acquisition tilt angle respectively, the PPG signal enhancement method further includes: When the target user wears the smart ring, the emission angle of the LED module, the receiving angle of the PD module, and the LED-PD line spacing between the LED module and the PD module are obtained. The maximum acquisition distance is calculated based on the transmission angle, reception angle, and size data. The smart ring collects pressure values ​​and finger skin characteristics; Calculate the equivalent thickness for PPG signal acquisition based on finger skin characteristics; The effective signal strength is generated based on the transmission angle, reception angle, LED-PD linear spacing, PPG signal acquisition equivalent thickness, and extrusion pressure value. When the effective signal strength does not reach the preset threshold, the tilt of the LED module and PD module is adjusted.

[0008] Optionally, the step of generating the effective signal strength based on the transmission angle, reception angle, LED-PD linear spacing, PPG signal acquisition equivalent thickness, and extrusion pressure value specifically includes: The average penetration index is calculated based on the LED-PD linear spacing, emission angle, reception angle, and PPG signal acquisition equivalent thickness. The average penetration index represents the simulated expected LED signal depth under the current default angle. Attenuation coefficients are generated based on equivalent thickness, extrusion pressure, and average penetration index acquired from PPG signals. The effective signal strength is generated based on the LED emitted light intensity, attenuation coefficient, and maximum acquisition distance during PPG signal acquisition.

[0009] Optionally, when the effective signal strength does not reach the preset threshold, the steps for adjusting the tilt of the LED module and PD module specifically include: When the effective signal strength does not reach the preset threshold, the signal strength difference is calculated based on the effective signal strength and the LED emitted light intensity when the PPG signal is acquired. The tilt of the LED module and PD module is adjusted based on the signal strength difference to reduce the maximum acquisition distance.

[0010] Optional, finger skin characteristics include skin surface thickness and melanin concentration index; The specific steps involved in collecting pressure values ​​and finger skin characteristics using a smart ring include: The squeezing pressure value is collected by a pressure sensor on the smart ring; The LED module emits a light signal of a preset wavelength at the current emission angle, and the PD module collects the reflected light intensity. The light signal of the preset wavelength includes at least a light signal for initial thickness detection and a light signal for melanin detection. The relative reflectivity is calculated based on the reflected light intensity and the calibration value, where the calibration value is the reference reflected light intensity obtained by pre-calibrating using a white reflective surface. The skin surface thickness and melanin concentration index are calculated based on the relative reflectance.

[0011] Optionally, the step of calculating the equivalent thickness of PPG signal acquisition based on finger skin characteristics specifically includes: Melanin concentration is determined based on the melanin concentration index; The equivalent thickness of melanin is calculated by the melanin concentration, the light signal used for melanin detection, and the corresponding reflected light intensity. The equivalent thickness of PPG signal acquisition is calculated based on the equivalent thickness of melanin and the thickness of the skin surface.

[0012] Secondly, this application provides a PPG signal enhancement device based on a smart ring, comprising: The horizontal spacing acquisition unit is used to acquire the horizontal spacing between LEDs and PDs on the PCB board. The horizontal spacing between LEDs and PDs is the distance between the LED modules and PD modules on the PCB board. The curvature tilt angle generation unit is used to generate the curvature tilt angle based on the size data of the smart ring and the horizontal spacing between the LED and PD after the PCB board is installed on the smart ring. The curvature tilt angle is the natural tilt angle caused by the curvature formed by the LED module and the PD module. The transmit / acquisition tilt angle generation unit is used to generate transmit tilt angle and acquisition tilt angle for the LED module and PD module respectively based on the curvature tilt angle. The tilt processing unit is used to tilt the LED module and the PD module according to the emission tilt angle and the acquisition tilt angle, respectively.

[0013] Optionally, the tilt processing unit specifically includes: The LED module is tilted according to the emission tilt angle so that the main light-emitting axis of the LED module is deflected from the direction perpendicular to the skin to the direction away from the PD module; The PD module is tilted according to the acquisition tilt angle so that the receiving main axis of the PD module is deflected from the direction perpendicular to the skin to the direction closer to the LED module.

[0014] Optionally, after the tilt processing unit, the PPG signal enhancement device further includes: The structural parameter acquisition unit is used to acquire the emission angle of the LED module, the receiving angle of the PD module, and the LED-PD straight-line spacing between the LED module and the PD module when the target user wears the smart ring. The maximum acquisition distance calculation unit is used to calculate the maximum acquisition distance based on the transmission angle, reception angle, and size data. The extrusion pressure value and finger skin feature acquisition unit is used to acquire extrusion pressure value and finger skin feature through the smart ring; The PPG signal acquisition equivalent thickness calculation unit is used to calculate the PPG signal acquisition equivalent thickness based on the characteristics of finger skin. An effective signal strength generation unit is used to generate an effective signal strength based on the transmission angle, reception angle, LED-PD linear spacing, PPG signal acquisition equivalent thickness, and extrusion pressure value. The tilt adjustment processing unit is used to adjust the tilt of the LED module and PD module when the effective signal strength does not reach the preset threshold.

[0015] Optionally, the effective signal strength generation unit specifically includes: The average penetration index is calculated based on the LED-PD linear spacing, emission angle, reception angle, and PPG signal acquisition equivalent thickness. The average penetration index represents the simulated expected LED signal depth under the current default angle. Attenuation coefficients are generated based on equivalent thickness, extrusion pressure, and average penetration index acquired from PPG signals. The effective signal strength is generated based on the LED emitted light intensity, attenuation coefficient, and maximum acquisition distance during PPG signal acquisition.

[0016] Optionally, the tilt adjustment processing unit specifically includes: When the effective signal strength does not reach the preset threshold, the signal strength difference is calculated based on the effective signal strength and the LED emitted light intensity when the PPG signal is acquired. The tilt of the LED module and PD module is adjusted based on the signal strength difference to reduce the maximum acquisition distance.

[0017] Optional, finger skin characteristics include skin surface thickness and melanin concentration index; The pressure value and finger skin feature acquisition unit specifically includes: The squeezing pressure value is collected by a pressure sensor on the smart ring; The LED module emits a light signal of a preset wavelength at the current emission angle, and the PD module collects the reflected light intensity. The light signal of the preset wavelength includes at least a light signal for initial thickness detection and a light signal for melanin detection. The relative reflectivity is calculated based on the reflected light intensity and the calibration value, where the calibration value is the reference reflected light intensity obtained by pre-calibrating using a white reflective surface. The skin surface thickness and melanin concentration index are calculated based on the relative reflectance.

[0018] Optionally, the PPG signal acquisition equivalent thickness calculation unit specifically includes: Melanin concentration is determined based on the melanin concentration index; The equivalent thickness of melanin is calculated by the melanin concentration, the light signal used for melanin detection, and the corresponding reflected light intensity. The equivalent thickness of PPG signal acquisition is calculated based on the equivalent thickness of melanin and the thickness of the skin surface.

[0019] Thirdly, this application provides a PPG signal enhancement device based on a smart ring, comprising: Processor, memory, input / output units, and bus; The processor is connected to memory, input / output units, and a bus; The memory stores a program, which the processor calls to execute, such as the first aspect and any optional PPG signal enhancement method of the first aspect.

[0020] Fourthly, this application provides a computer-readable storage medium storing a program that, when executed on a computer, performs the PPG signal enhancement method as described in the first aspect and any optional method of the first aspect.

[0021] As can be seen from the above technical solutions, this application has the following advantages: First, the horizontal spacing between the LED and PD modules on the PCB board is obtained, where the horizontal spacing is the distance between the LED module and the PD module on the PCB board. After the PCB board is installed on the smart ring, a curvature tilt angle is generated based on the size data of the smart ring and the horizontal spacing between the LED and PD modules. The curvature tilt angle is the natural tilt angle caused by the curvature formed by the LED module and the PD module, thus simulating the effect of finger curvature. Based on the curvature tilt angle, emission tilt angle and acquisition tilt angle are generated for the LED module and the PD module respectively. Finally, the LED module and the PD module are tilted according to the emission tilt angle and the acquisition tilt angle respectively. By giving the LED module and the PD module a emission angle and a reception angle, and considering the cylindrical geometry of the finger, the emission angle and reception angle are adjusted to improve the acquisition strength of the PPG signal of the smart ring. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the PPG signal enhancement method based on a smart ring according to this application; Figure 2 This is a schematic diagram of the method for tilting the LED module and PD module according to this application; Figure 3 This is a schematic diagram illustrating the method for adjusting the tilt of the LED module and PD module according to this application; Figure 4 A schematic diagram of a method for generating effective signal strength for this application; Figure 5 This is a schematic diagram of the tilt adjustment method of this application; Figure 6 This is a schematic diagram illustrating the method for collecting pressure values ​​and finger skin characteristics according to this application; Figure 7 This is a schematic diagram of the method for calculating the equivalent thickness of PPG signal acquisition in this application; Figure 8 This is a schematic diagram of the PPG signal enhancement device based on a smart ring according to this application; Figure 9 This is another schematic diagram of the PPG signal enhancement device based on a smart ring according to this application. Detailed Implementation

[0024] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0025] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0026] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0027] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0028] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0029] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0030] This application discloses a PPG signal enhancement method, apparatus, and storage medium based on a smart ring, used to improve the acquisition strength of the PPG signal from the smart ring.

[0031] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0032] The method described in this application can be applied to servers, devices, terminals, or other devices with logical processing capabilities; therefore, this application does not limit its application. For ease of description, the following description uses a terminal as the executing entity.

[0033] Please see Figure 1 This application provides an embodiment of a PPG signal enhancement method based on a smart ring, comprising: 101. Obtain the horizontal spacing between LEDs and PDs on the PCB board. The horizontal spacing between LEDs and PDs is the distance between the LED modules and PD modules on the PCB board. In this embodiment, in order to fully consider the cylindrical geometric features of the finger, the horizontal distance between the LED and the PD module needs to be obtained before the PCB board is installed on the smart ring. The horizontal distance between the LED and the PD module is the straight-line distance between the LED module and the PD module when the PCB board is not bent.

[0034] 102. After the PCB board is installed on the smart ring, the curvature tilt angle is generated based on the size data of the smart ring and the horizontal spacing between the LED and PD modules. The curvature tilt angle is the natural tilt angle caused by the curvature formed by the LED module and the PD module. After obtaining the straight-line distance between the LED module and the PD module in the unbent state of the PCB board, the PCB board is mounted onto the surface of the inner cavity of the smart ring, specifically close to the surface of the inner cavity, causing the PCB board to bend. At this point, the LED module and the PD module are aligned with the emission port and the acquisition port on the smart ring. Then, based on the size data of the smart ring and the horizontal spacing between the LED and PD, a curvature tilt angle is generated. That is, the horizontal spacing between the LED and PD becomes part of the inner circumference of the smart ring. The curvature tilt angle is calculated using the circumference information in the size data and the horizontal spacing between the LED and PD, and this curvature tilt angle is the central angle occupied by the horizontal spacing between the LED and PD.

[0035] 103. Generate the emission tilt angle and acquisition tilt angle for the LED module and PD module respectively based on the curvature tilt angle; At this point, the terminal generates emission tilt angles and acquisition tilt angles for the LED module and PD module respectively, based on the curvature tilt angle. Specifically, it first determines the initial tilt angles of the LED module and PD module, which are pre-designed target optical tilt angles. Then, it performs finger curvature compensation on the target optical tilt angle, that is, it adjusts the target optical tilt angle using the curvature tilt angle. A specific example is given below: The inner ring of the ring is cylindrical. The tilt angles of the LED and PD modules need to be compensated for by the curvature of the finger. For a ring with an inner diameter of 18mm, the horizontal spacing between the LED and PD corresponds to a curvature tilt angle of approximately 19°. The natural curvature tilt angle is approximately 19° / 4≈4.75°, which gives the following formula: Actual PCB mounting tilt angle = Target optical tilt angle - Curvature natural tilt angle The actual PCB mounting tilt angle is the same as the emission tilt angle and the acquisition tilt angle. Assuming the target α = 10° and the curvature compensation is 4.75°, the actual tilt of the LED on the PCB module is 5.25°, and the emission tilt angle can be deduced accordingly.

[0036] 104. Tilt the LED module and PD module according to the transmission tilt angle and the acquisition tilt angle respectively.

[0037] After the terminal calculates the transmission tilt angle and the acquisition tilt angle, it can then tilt the LED module and the PD module according to these angles. The specific tilting methods will be described in detail in subsequent embodiments.

[0038] Experiments showed that when the target optical tilt angle of the LED module was 10°, after curvature compensation, the number of photons reaching a depth of 2mm increased by 40%–60% compared to perpendicular incidence. When the target optical tilt angle of the PD module was 10°, after compensation, the probability of scattered photons from a depth of 2mm being captured by the PD module increased by 25%–35%. When the LED and PD modules were tilted together, the PPG AC signal amplitude increased by 50%–80%, the DC baseline change was <10%, and the net PI increased by 45%–70%.

[0039] First, the horizontal spacing between the LED and PD modules on the PCB board is obtained, where the horizontal spacing is the distance between the LED module and the PD module on the PCB board. After the PCB board is installed on the smart ring, a curvature tilt angle is generated based on the size data of the smart ring and the horizontal spacing between the LED and PD modules. The curvature tilt angle is the natural tilt angle caused by the curvature formed by the LED module and the PD module, thus simulating the effect of finger curvature. Based on the curvature tilt angle, emission tilt angle and acquisition tilt angle are generated for the LED module and the PD module respectively. Finally, the LED module and the PD module are tilted according to the emission tilt angle and the acquisition tilt angle respectively. By giving the LED module and the PD module a emission angle and a reception angle, and considering the cylindrical geometry of the finger, the emission angle and reception angle are adjusted to improve the acquisition strength of the PPG signal of the smart ring.

[0040] Please see Figure 2 This application provides an embodiment of a method for tilting LED modules and PD modules, comprising: 201. Tilt the LED module according to the emission tilt angle so that the main light-emitting axis of the LED module deflects from the direction perpendicular to the skin to the direction away from the PD module; 202. The PD module is tilted according to the acquisition tilt angle so that the receiving main axis of the PD module is deflected from the direction perpendicular to the skin to the direction closer to the LED module.

[0041] In this embodiment, the LED module needs to be installed at an outward tilt. The mounting surface of the LED module is tilted outward at an angle α relative to the inner tangent of the smart ring, which is the target optical tilt angle of the LED module. The target optical tilt angle α ranges from 5-15°, preferably 8-12°. The light-emitting main axis of the LED module is deflected from the direction perpendicular to the skin towards the direction away from the PD module.

[0042] The detection light signal emitted by the LED enters the skin at a larger incident angle. According to Snell's law, it is refracted at a larger angle at the skin-tissue interface, and the light path is deflected to the deeper layers, increasing the light energy reaching the digital artery layer.

[0043] The target's natural tilt angle is related to the linear spacing between the LEDs and the PDs. When the spacing is 3mm, the target's natural tilt angle α_opt≈10°, and when the spacing is 4mm, the target's natural tilt angle α_opt≈8°.

[0044] The PD module is installed at an inward tilt, with the mounting surface of the PD module tilted inward at an angle β relative to the inner tangent of the smart ring. This angle β is the target optical tilt angle of the PD module, which ranges from 5-15°, preferably 8-12°. The receiving axis of the PD module is deflected from a direction perpendicular to the skin towards the LED. At this time, the receiving cone of the PD module covers more of the light scattered back from deep tissues, improving the acquisition efficiency of arterial pulsation signals.

[0045] Please see Figure 3 This application provides an embodiment of a method for tilt adjustment of LED modules and PD modules, comprising: 301. When the target user wears the smart ring, obtain the emission angle of the LED module, the receiving angle of the PD module, and the LED-PD straight-line distance between the LED module and the PD module; Besides the cylindrical geometry of the fingers, the finger characteristics of each smart ring wearer remain a key factor affecting the quality of PPG signal acquisition, especially the thickness and melanin concentration of the finger skin. These two finger characteristics have a stronger absorption effect on shallow light signals. Furthermore, the pressure exerted on the fingers by the smart ring during wear also affects the final effective light signal acquired. In this embodiment, the emission angle is adjusted based on the user's finger skin characteristics and cylindrical geometry to reduce light signal loss caused by skin thickness, melanin concentration, and ring pressure, achieving better acquisition results without adjusting light signal parameters.

[0046] Specifically, after tilting the LED module and PD module according to the emission tilt angle and the acquisition tilt angle respectively, the target user wears the smart ring, and the current emission angle of the LED module and PD module is recorded. (Relative to skin normal) and receiving angle (Relative to the skin normal), then calculate the LED-PD linear spacing d between the LED module and the PD module. The LED-PD linear spacing d can be calculated using the LED-PD horizontal spacing and the size data of the smart ring.

[0047] 302. Calculate the maximum acquisition distance based on the transmission angle, reception angle, and size data; Next, the terminal calculates the maximum acquisition distance based on the transmission angle, reception angle, and size data. That is, it determines the positions of the LED module and PD module on the smart ring based on the size data, and then draws the transmission ray segment and reflection line segment based on the transmission angle and reception angle. Combining the transmission line segment and the reflection line segment forms the maximum acquisition distance L.

[0048] 303. Collect squeezing pressure values ​​and finger skin characteristics through a smart ring; In this embodiment, the terminal collects the squeezing pressure value and finger skin characteristics through the sensor on the smart ring. The specific collection method will be described in detail in subsequent embodiments. The finger skin characteristics mainly include skin thickness and melanin concentration index.

[0049] 304. Calculate the equivalent thickness of PPG signal acquisition based on the characteristics of finger skin; In this embodiment, the terminal calculates the equivalent thickness of PPG signal acquisition based on finger skin characteristics (skin thickness and melanin concentration index). The specific calculation method will be described in detail in subsequent embodiments.

[0050] 305. Generate effective signal strength based on the transmission angle, reception angle, LED-PD linear spacing, PPG signal acquisition equivalent thickness, and extrusion pressure value; In this embodiment, the terminal generates an effective signal strength based on the transmission angle, reception angle, LED-PD linear spacing, PPG signal acquisition equivalent thickness, and extrusion pressure value. The specific calculation method will be described in detail in subsequent embodiments.

[0051] 306. When the effective signal strength does not reach the preset threshold, the tilt of the LED module and PD module is adjusted.

[0052] When the terminal determines that the effective signal strength has not reached the threshold, it adaptively adjusts the transmission and reception angles of the LED module and PD module based on parameters such as the current effective signal strength, so that the acquisition depth is within the preset range. At the same time, it adjusts the maximum acquisition distance appropriately by adjusting the transmission and reception angles to improve the effective signal strength.

[0053] Please see Figure 4 This application provides an embodiment of a method for generating effective signal strength, comprising: 401. Calculate the average penetration index based on the LED-PD linear spacing, emission angle, reception angle, and PPG signal acquisition equivalent thickness. The average penetration index represents the simulated expected LED signal depth under the current default angle. In this embodiment, the terminal first calculates the average penetration index based on the LED-PD linear spacing, emission angle, reception angle, and PPG signal acquisition equivalent thickness. The average penetration index refers to the maximum detection depth that can be achieved under the current emission and reception angles, and the position between the LED module and the PD module. The formula is as follows:

[0054] in, Where is the equivalent thickness for PPG signal acquisition and D is the average penetration index. In this embodiment, the terminal uses the equivalent thickness for PPG signal acquisition to correct the ideal detection depth value, so that the subsequent effective signal strength is more accurate.

[0055] 402. Generate the attenuation coefficient based on the equivalent thickness, extrusion pressure value, and average penetration index acquired from the PPG signal; Next, the terminal generates an attenuation coefficient based on the equivalent thickness, extrusion pressure, and average penetration index acquired from the PPG signal. The formula is as follows:

[0056] in, The minimum reference compressive force that the smart ring can detect. This is a standard skin thickness reference value. and These are empirical calibration coefficients for extrusion pressure and skin thickness, respectively, obtained through experiments.

[0057] 403. Generate the effective signal strength based on the LED emitted light intensity, attenuation coefficient, and maximum acquisition distance during PPG signal acquisition.

[0058] After obtaining the average penetration index and attenuation coefficient, the terminal can generate the effective signal strength based on the LED emitted light intensity, attenuation coefficient, and maximum acquisition distance during PPG signal acquisition. The formula is as follows:

[0059] Where I represents the LED emitted light intensity during PPG signal acquisition, and L represents the maximum acquisition distance. The effective signal strength calculated in the above manner can be used for loss analysis based on the user's skin characteristics and the current PPG signal detection parameters. It can determine whether further adjustments to the transmission and reception angles are needed.

[0060] Please see Figure 5 This application provides an embodiment of a tilt adjustment processing method, comprising: 501. When the effective signal strength does not reach the preset threshold, calculate the signal strength difference based on the effective signal strength and the LED emitted light intensity when the PPG signal is acquired. 502. Adjust the tilt of the LED module and PD module according to the signal strength difference to reduce the maximum acquisition distance.

[0061] In this embodiment, when the effective signal strength does not reach the preset threshold, the signal strength difference between the effective signal strength and the LED emitted light intensity during PPG signal acquisition needs to be calculated. The angle is then adjusted based on this difference. The adjustment direction is as follows: the LED module's emitting axis deflects from the direction perpendicular to the skin towards the PD module, and the PD module's receiving axis deflects from the direction perpendicular to the skin away from the LED module, thereby reducing the maximum acquisition distance. In this embodiment, adjustment can be performed according to a preset angle step size, or a one-time adjustment can be made using the signal strength difference; this is not limited here.

[0062] Please see Figure 6 This application provides an embodiment of a method for collecting squeezing pressure values ​​and finger skin characteristics, wherein the finger skin characteristics include skin surface thickness values ​​and melanin concentration index, including: 601. The squeezing pressure value is collected through the pressure sensor on the smart ring; In this embodiment, a pressure sensor on the smart ring is used to collect the squeezing force of the finger on the smart ring, thereby generating a squeezing force value P.

[0063] 602. The LED module emits a light signal of a preset wavelength at the current emission angle, and the PD module collects the reflected light intensity. The light signal of the preset wavelength includes at least a light signal for initial thickness detection and a light signal for melanin detection. 603. Calculate the relative reflectivity based on the reflected light intensity and the calibration value, where the calibration value is the reference reflected light intensity obtained by pre-calibrating using a white reflective surface; 604. Calculate the skin surface thickness and melanin concentration index based on relative reflectance.

[0064] The terminal emits a light signal of a preset wavelength at the current emission angle through the LED module, wherein the light signal of the preset wavelength includes at least a light signal for initial thickness detection and a light signal for melanin detection.

[0065] Specifically, the LED module is equipped with LEDs of different short wavelengths for detecting the shallowest layer at 340nm and blue light at 470nm. These two short wavelengths are used for initial thickness detection. The terminal can calculate the relative reflectivity based on the reflected light intensity and the calibration value. The calibration value is the reference reflected light intensity obtained by pre-calibration using a white reflective surface, and the specific formula is as follows:

[0066]

[0067]

[0068] in, After wearing the smart ring, the PD module or other photodiodes will be in wavelength range. The light intensity measured below, To perform pre-calibration using a white reflective surface before wearing, the PD module or other photodiodes are at the wavelength... The calibrated light intensity value obtained from the measurement. and The values ​​are the relative reflectance at wavelengths of 340 nm and 470 nm, respectively. T is the skin surface thickness, and a and b are coefficients determined through optical simulation or tissue experiments, which are known values.

[0069] After calculating the skin surface thickness, the melanin concentration index uses short-wavelength LEDs of 425nm, 540nm, and 660nm, as shown in the following formula:

[0070]

[0071] in, The relative reflectance at a wavelength of 405 nm. The baseline relative reflectance can be estimated from the reflectance at 540 nm and 660 nm. Calculations using these two wavelengths avoid the strong absorption peak of melanin. M is the melanin concentration index, k is a scaling factor determined through experimental calibration, and m is an offset constant. Together with the scaling factor k, the ratio is linearly transformed to a specified range of melanin concentration index M values.

[0072] Please see Figure 7 This application provides an embodiment of a method for calculating the equivalent thickness of PPG signal acquisition, comprising: 701. Determine melanin concentration based on the melanin concentration index; 702. Calculate the equivalent thickness of melanin using melanin concentration, the light signal used for melanin detection, and the corresponding reflected light intensity; 703. Calculate the equivalent thickness of PPG signal acquisition based on the melanin equivalent thickness and the skin surface thickness value.

[0073] When the terminal determines the user's melanin concentration from the experimental database based on the calculated melanin concentration index, it calculates the equivalent melanin thickness using the melanin concentration, the light signal used for melanin detection, and the corresponding reflected light intensity. The specific formula is as follows:

[0074] Where C represents the melanin concentration in the user's finger. Equivalent thickness of melanin To ensure the optical signal used for melanin detection passes through the dermis, blood vessels, and other tissues in the absence of additional melanin absorption, the basic fixed optical path length is determined using a standard skin color test and is a known parameter. is the molar extinction coefficient of melanin, representing the absorption capacity of a unit concentration of melanin for light at a wavelength of 405 nm per unit optical path length. The light intensity emitted by the LED module of the smart ring when detecting melanin. The light intensity received when the PD module of the smart ring performs melanin detection.

[0075] Finally, the terminal is based on the melanin equivalent thickness. The equivalent thickness of PPG signal acquisition is calculated using the skin surface thickness value T. The formula is as follows:

[0076] Please see Figure 8 This application provides an embodiment of a PPG signal enhancement device based on a smart ring, comprising: The horizontal spacing acquisition unit 801 is used to acquire the horizontal spacing between LEDs and PDs on the PCB board. The horizontal spacing between LEDs and PDs is the distance between the LED modules and PD modules on the PCB board. The curvature tilt angle generation unit 802 is used to generate the curvature tilt angle based on the size data of the smart ring and the horizontal spacing between the LED and PD after the PCB board is installed on the smart ring. The curvature tilt angle is the natural tilt angle caused by the curvature formed by the LED module and the PD module. The transmit / acquisition tilt angle generation unit 803 is used to generate transmit tilt angle and acquisition tilt angle for LED module and PD module respectively according to curvature tilt angle; The tilt processing unit 804 is used to tilt the LED module and the PD module according to the emission tilt angle and the acquisition tilt angle, respectively.

[0077] Optionally, the tilt processing unit 804 specifically includes: The LED module is tilted according to the emission tilt angle so that the main light-emitting axis of the LED module is deflected from the direction perpendicular to the skin to the direction away from the PD module; The PD module is tilted according to the acquisition tilt angle so that the receiving main axis of the PD module is deflected from the direction perpendicular to the skin to the direction closer to the LED module.

[0078] Optionally, after the tilt processing unit, the PPG signal enhancement device further includes: The structural parameter acquisition unit is used to acquire the emission angle of the LED module, the receiving angle of the PD module, and the LED-PD straight-line spacing between the LED module and the PD module when the target user wears the smart ring. The maximum acquisition distance calculation unit is used to calculate the maximum acquisition distance based on the transmission angle, reception angle, and size data. The extrusion pressure value and finger skin feature acquisition unit is used to acquire extrusion pressure value and finger skin feature through the smart ring; The PPG signal acquisition equivalent thickness calculation unit is used to calculate the PPG signal acquisition equivalent thickness based on the characteristics of finger skin. An effective signal strength generation unit is used to generate an effective signal strength based on the transmission angle, reception angle, LED-PD linear spacing, PPG signal acquisition equivalent thickness, and extrusion pressure value. The tilt adjustment processing unit is used to adjust the tilt of the LED module and PD module when the effective signal strength does not reach the preset threshold.

[0079] Optionally, the effective signal strength generation unit specifically includes: The average penetration index is calculated based on the LED-PD linear spacing, emission angle, reception angle, and PPG signal acquisition equivalent thickness. The average penetration index represents the simulated expected LED signal depth under the current default angle. Attenuation coefficients are generated based on equivalent thickness, extrusion pressure, and average penetration index acquired from PPG signals. The effective signal strength is generated based on the LED emitted light intensity, attenuation coefficient, and maximum acquisition distance during PPG signal acquisition.

[0080] Optionally, the tilt adjustment processing unit specifically includes: When the effective signal strength does not reach the preset threshold, the signal strength difference is calculated based on the effective signal strength and the LED emitted light intensity when the PPG signal is acquired. The tilt of the LED module and PD module is adjusted based on the signal strength difference to reduce the maximum acquisition distance.

[0081] Optional, finger skin characteristics include skin surface thickness and melanin concentration index; The pressure value and finger skin feature acquisition unit specifically includes: The squeezing pressure value is collected by a pressure sensor on the smart ring; The LED module emits a light signal of a preset wavelength at the current emission angle, and the PD module collects the reflected light intensity. The light signal of the preset wavelength includes at least a light signal for initial thickness detection and a light signal for melanin detection. The relative reflectivity is calculated based on the reflected light intensity and the calibration value, where the calibration value is the reference reflected light intensity obtained by pre-calibrating using a white reflective surface. The skin surface thickness and melanin concentration index are calculated based on the relative reflectance.

[0082] Optionally, the PPG signal acquisition equivalent thickness calculation unit specifically includes: Melanin concentration is determined based on the melanin concentration index; The equivalent thickness of melanin is calculated by the melanin concentration, the light signal used for melanin detection, and the corresponding reflected light intensity. The equivalent thickness of PPG signal acquisition is calculated based on the equivalent thickness of melanin and the thickness of the skin surface.

[0083] Please see Figure 9 This application provides a PPG signal enhancement device based on a smart ring, comprising: Processor 901, memory 902, input / output unit 903, and bus 904.

[0084] The processor 901 is connected to the memory 902, the input / output unit 903, and the bus 904.

[0085] The memory 902 stores a program, and the processor 901 calls the program to execute it, such as... Figure 1 , Figure 2 and Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 PPG signal enhancement method in [the context of the text].

[0086] This application provides a computer-readable storage medium on which a program is stored, and when the program is executed on a computer, it performs the following actions: Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 PPG signal enhancement method in [the context of the text].

[0087] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0088] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0089] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0090] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0091] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A PPG signal enhancement method based on a smart ring, characterized in that, include: Obtain the horizontal spacing between LEDs and PDs on the PCB board, where the horizontal spacing between LEDs and PDs is the distance between the LED modules and PD modules on the PCB board; After the PCB board is installed on the smart ring, a curvature tilt angle is generated based on the size data of the smart ring and the horizontal spacing between the LED and PD modules. The curvature tilt angle is the natural tilt angle caused by the curvature formed by the LED module and the PD module. Based on the curvature tilt angle, emission tilt angle and acquisition tilt angle are generated for the LED module and the PD module, respectively; The LED module and the PD module are tilted according to the emission tilt angle and the acquisition tilt angle, respectively.

2. The PPG signal enhancement method according to claim 1, characterized in that, The step of tilting the LED module and the PD module according to the emission tilt angle and the acquisition tilt angle respectively specifically includes: The LED module is tilted according to the emission tilt angle so that the main light-emitting axis of the LED module is deflected from the direction perpendicular to the skin to the direction away from the PD module; The PD module is tilted according to the acquisition tilt angle so that the receiving axis of the PD module is deflected from the direction perpendicular to the skin to the direction closer to the LED module.

3. The PPG signal enhancement method according to any one of claims 1 to 2, characterized in that, After the step of tilting the LED module and the PD module according to the emission tilt angle and the acquisition tilt angle respectively, the PPG signal enhancement method further includes: When the target user wears the smart ring, the emission angle of the LED module, the receiving angle of the PD module, and the LED-PD straight-line distance between the LED module and the PD module are obtained. The maximum acquisition distance is calculated based on the transmission angle, the reception angle, and the size data; The smart ring collects pressure values ​​and finger skin characteristics. The equivalent thickness for PPG signal acquisition is calculated based on the described finger skin characteristics; An effective signal strength is generated based on the emission angle, the reception angle, the LED-PD linear spacing, the PPG signal acquisition equivalent thickness, and the extrusion pressure value. When the effective signal strength does not reach the preset threshold, the tilt of the LED module and the PD module is adjusted.

4. The PPG signal enhancement method according to claim 3, characterized in that, The step of generating an effective signal strength based on the emission angle, the reception angle, the LED-PD linear spacing, the PPG signal acquisition equivalent thickness, and the extrusion pressure value specifically includes: The average penetration index is calculated based on the LED-PD linear spacing, the emission angle, the reception angle, and the equivalent thickness of the PPG signal acquisition. The average penetration index represents the simulated expected LED signal depth under the current default angle. An attenuation coefficient is generated based on the equivalent thickness acquired from the PPG signal, the extrusion pressure value, and the average penetration index. The effective signal strength is generated based on the LED emitted light intensity during PPG signal acquisition, the attenuation coefficient, and the maximum acquisition distance.

5. The PPG signal enhancement method according to claim 4, characterized in that, The step of adjusting the tilt of the LED module and the PD module when the effective signal strength does not reach the preset threshold specifically includes: When the effective signal strength does not reach the preset threshold, the signal strength difference is calculated based on the effective signal strength and the LED emitted light intensity when the PPG signal is acquired. The tilt of the LED module and the PD module is adjusted based on the signal strength difference to reduce the maximum acquisition distance.

6. The PPG signal enhancement method according to claim 3, characterized in that, The finger skin characteristics include skin surface thickness and melanin concentration index; The steps of collecting the pressure value and finger skin characteristics through the smart ring specifically include: The pressure value is collected by a pressure sensor on the smart ring; The LED module emits a light signal of a preset wavelength at the current emission angle, and the PD module collects the reflected light intensity. The light signal of the preset wavelength includes at least a light signal for initial thickness detection and a light signal for melanin detection. The relative reflectivity is calculated based on the reflected light intensity and the calibration value, wherein the calibration value is a reference reflected light intensity obtained by pre-calibration using a white reflective surface. The skin surface thickness and melanin concentration index are calculated based on the relative reflectance.

7. The PPG signal enhancement method according to claim 6, characterized in that, The step of calculating the equivalent thickness of PPG signal acquisition based on the finger skin characteristics specifically includes: Melanin concentration is determined based on the melanin concentration index; The equivalent thickness of melanin is calculated using the melanin concentration, the light signal used for melanin detection, and the corresponding reflected light intensity. The equivalent thickness of PPG signal acquisition is calculated based on the equivalent thickness of melanin and the thickness of the skin surface.

8. A PPG signal enhancement method based on a smart ring, characterized in that, include: A horizontal spacing acquisition unit is used to acquire the horizontal spacing between LEDs and PDs on a PCB board, wherein the horizontal spacing between LEDs and PDs is the distance between the LED modules and PD modules on the PCB board; A curvature tilt angle generation unit is used to generate a curvature tilt angle based on the size data of the smart ring and the horizontal spacing between the LED and PD after the PCB board is installed on the smart ring. The curvature tilt angle is the natural tilt angle caused by the curvature formed by the LED module and the PD module. The transmit / acquisition tilt angle generation unit is used to generate transmit tilt angle and acquisition tilt angle for the LED module and the PD module respectively according to the curvature tilt angle; The tilt processing unit is used to tilt the LED module and the PD module according to the emission tilt angle and the acquisition tilt angle, respectively.

9. A PPG signal enhancement device based on a smart ring, characterized in that, The device includes: Processor, memory, input / output units, and bus; The processor is connected to memory, input / output units, and a bus; The memory stores a program, which the processor calls to execute the PPG signal enhancement method as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a program stored thereon, which, when executed on a computer, performs the PPG signal enhancement method as claimed in any one of claims 1 to 7.

Images