Blood oxygen detection method, blood oxygen detection device and computer readable storage medium

Abstract

Embodiments of the present application provide a blood oxygen detection method, a blood oxygen detection device and a computer readable storage medium, wherein the blood oxygen detection method comprises: determining a first blood perfusion index under common irradiation of a red light source and a green light source; and determining a second blood perfusion index under irradiation of an infrared light source; and determining a blood oxygen detection result according to the first blood perfusion index and the second blood perfusion index. In this way, the accuracy of blood oxygen detection can be improved.

Description

Technical Field

[0001] This application relates to the field of blood oxygen detection technology, specifically to a blood oxygen detection method, a blood oxygen detection device, and a computer-readable storage medium. Background Technology

[0002] Blood oxygen saturation characterizes the oxygen content in human blood, effectively reflecting the physiological state of the circulatory and respiratory systems, and plays a positive role in diagnosis and health monitoring. Currently, wearable non-invasive blood oxygenation methods are widely used. However, when PPG (photoplethysmograph) measurement technology is used for wearable blood oxygen measurement, it suffers from problems such as motion artifacts, tightness of the garment, environmental interference, and differences in skin surface characteristics, leading to low measurement accuracy and large errors. In particular, measurements under normoxic conditions are easily affected by pseudo-hypoxia. Summary of the Invention

[0003] This application provides a blood oxygen detection method, a blood oxygen detection device, and a computer-readable storage medium, which can improve the accuracy of blood oxygen detection.

[0004] This application provides a blood oxygen detection method, which includes: determining a first blood perfusion index under the combined illumination of a red light source and a green light source; determining a second blood perfusion index under the illumination of an infrared light source; and determining a blood oxygen detection result based on the first blood perfusion index and the second blood perfusion index.

[0005] In some embodiments, determining the first blood perfusion index under the combined illumination of a red light source and a green light source includes: driving the red light source and the green light source according to a current compensation coefficient; acquiring a first pulse wave signal under the combined illumination of the red light source and the green light source; and determining the first blood perfusion index based on the first pulse wave signal and the red light blood perfusion compensation parameter.

[0006] In some embodiments, driving a red light source and a green light source according to a current compensation coefficient includes: obtaining a first current parameter and a current compensation coefficient; compensating the first current parameter using the current compensation coefficient to obtain a second current parameter; driving the red light source based on the first current parameter and driving the green light source based on the second current parameter.

[0007] In some embodiments, determining a first blood flow perfusion index based on a first pulse wave signal and red light blood flow perfusion compensation parameters includes: acquiring red light blood flow perfusion compensation parameters; determining an initial blood flow perfusion index based on the first pulse wave signal; and compensating the initial blood flow perfusion index using the red light blood flow perfusion compensation parameters to obtain the first blood flow perfusion index.

[0008] In some embodiments, the method further includes: sequentially driving a red light source, a green light source, and an infrared light source; acquiring red pulse wave signals under red light source illumination, acquiring green pulse wave signals under green light source illumination, and acquiring infrared pulse wave signals under infrared light source illumination; determining a tension coefficient based on the green pulse wave signals and infrared pulse wave signals; determining a blood perfusion compensation ratio based on the tension coefficient; and determining a current compensation coefficient and a red blood perfusion compensation parameter based on the blood perfusion compensation ratio, the red pulse wave signals, and the green pulse wave signals.

[0009] In some embodiments, determining the tightness coefficient based on the green pulse wave signal and the infrared pulse wave signal includes: determining the green pulse wave perfusion index based on the green pulse wave signal and the infrared pulse wave perfusion index based on the infrared pulse wave signal; determining the theoretical value of green pulse wave perfusion based on the infrared pulse wave perfusion index; and determining the tightness coefficient based on the green pulse wave perfusion index and the theoretical value of green pulse wave perfusion.

[0010] In some embodiments, determining the blood perfusion compensation ratio based on the tension coefficient includes: determining the maximum blood perfusion compensation ratio corresponding to the maximum tension coefficient; and determining the current blood perfusion compensation ratio corresponding to the current tension coefficient; determining the current current compensation coefficient and the red blood perfusion compensation parameter based on the blood perfusion compensation ratio, the red pulse wave signal, and the green pulse wave signal includes: determining the red blood perfusion compensation parameter based on the maximum blood perfusion compensation ratio; and determining the current current compensation coefficient based on the maximum blood perfusion compensation ratio, the current blood perfusion compensation ratio, the red pulse wave signal, and the green pulse wave signal.

[0011] In some embodiments, determining the red light perfusion compensation parameter based on the maximum value of the perfusion compensation ratio includes: determining the red light perfusion compensation parameter using the following formula: PI R补偿 =PI 松佩戴 ×R 调整max Among them, PI R补偿 PI is the parameter for red light blood flow perfusion compensation. 松佩戴 R represents the red light perfusion index under loose wearing conditions. 调整max This represents the maximum blood perfusion compensation ratio.

[0012] In some embodiments, determining the current compensation coefficient based on the maximum blood perfusion compensation ratio, the current blood perfusion compensation ratio, the red pulse wave signal, and the green pulse wave signal includes: determining the red DC component based on the red pulse wave signal, and determining the green DC component and the green blood perfusion index based on the green pulse wave signal; determining the green blood perfusion compensation parameter based on the maximum blood perfusion compensation ratio and the current blood perfusion compensation ratio; determining the AC compensation parameter based on the red DC component and the green blood perfusion compensation parameter; and determining the current compensation coefficient based on the AC compensation parameter, the green DC component, and the green blood perfusion index.

[0013] In some embodiments, determining the green light blood perfusion compensation parameter based on the maximum value of the blood perfusion compensation ratio and the current value of the blood perfusion compensation ratio includes: determining the green light blood perfusion compensation parameter using the following formula: PI G补偿 =PI 松佩戴 ×(R 调整max -R 调整当前 ); where PI G补偿 PI is the parameter for green light blood flow perfusion compensation. 松佩戴 R represents the red light perfusion index under loose wearing conditions. 调整max R represents the maximum blood perfusion compensation ratio. 调整当前 This is the current value of the blood perfusion compensation ratio.

[0014] In some embodiments, determining the AC compensation parameters based on the red light DC component and the green light blood flow perfusion compensation parameters includes: determining the AC compensation parameters using the following formula: AC 补偿 =PI G补偿 ×DC R Among them, AC 补偿 To exchange compensation parameters, PI G补偿 For green light blood flow perfusion compensation parameters, DC R This is the DC component of red light.

[0015] In some embodiments, determining the current compensation coefficient based on AC compensation parameters, the DC component of green light, and the green light perfusion index includes: acquiring the red light driving current driving the red light source and acquiring the green light driving current driving the green light source; determining the green light current compensation value based on the AC compensation parameters, the green light perfusion index, the DC component of green light, and the green light driving current; and determining the current compensation coefficient based on the green light current compensation value and the red light driving current.

[0016] In some embodiments, determining the green light current compensation value based on AC compensation parameters, green light perfusion index, green light DC component, and green light driving current includes: determining the green light current compensation value using the following formula: I G补偿 =AC 补偿 / PIG / DC G ×I G Among them, I G补偿 This is the green photocurrent compensation value, AC 补偿 To exchange compensation parameters, PI G For green light blood flow perfusion index, DC G For the green light DC component, I G The current is driven by the green light.

[0017] In some embodiments, determining the current compensation coefficient based on the green light current compensation value and the red light driving current includes: determining the current compensation coefficient using the following formula: R 补偿 =I G补偿 / I R Among them, R 补偿 I is the current compensation coefficient. G补偿 I is the green photocurrent compensation value. R This is the current driven by the red light.

[0018] In some embodiments, the method further includes: detecting the wearing state; and determining a current compensation coefficient and a red light blood flow perfusion compensation parameter in response to a change in the wearing state.

[0019] In some embodiments, determining the blood oxygen detection result based on a first blood perfusion index and a second blood perfusion index includes: determining a blood perfusion ratio based on the first blood perfusion index and the second blood perfusion index; and determining the blood oxygen detection result based on the blood perfusion ratio.

[0020] This application also provides a blood oxygen detection device, which includes: a red light source, a green light source and an infrared light source; a light sensor; and a controller connected to the red light source, the green light source, the infrared light source and the light sensor, and the controller is used to perform the blood oxygen detection method as described above.

[0021] This application also provides a computer-readable storage medium storing program data, which, when executed by a processor, is used to implement the blood oxygen detection method described above.

[0022] The blood oxygen detection method provided in this application includes: determining a first blood perfusion index under the combined illumination of a red light source and a green light source; and determining a second blood perfusion index under the illumination of an infrared light source; and determining the blood oxygen detection result based on the first and second blood perfusion indices. Through this method, without increasing hardware costs, a blood oxygen measurement method is provided using three LEDs (red light, infrared light, and green light). By using direct optical path compensation, a certain proportion of green light is activated simultaneously with the red light, using the green light as a compensation component to automatically adjust and reduce the increase in venous components, thereby reducing the influence of false hypoxia signal components and improving measurement accuracy. Furthermore, since the red and green light are activated simultaneously, energy consumption can be reduced to a certain extent, increasing the battery life of wearable devices. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0024] Figure 1a This is a schematic diagram of the first depth detection in one embodiment;

[0025] Figure 1b This is a schematic diagram of the second depth detection in one embodiment;

[0026] Figure 2 This is a schematic flowchart of an embodiment of the blood oxygen detection method provided in this application;

[0027] Figure 3 yes Figure 2 A flowchart of an embodiment of step 21;

[0028] Figure 4 This is a schematic diagram of the structure of a wearable device in one embodiment;

[0029] Figure 5 This is a schematic flowchart of another embodiment of the blood oxygen detection method provided in this application;

[0030] Figure 6 yes Figure 5 A flowchart of an embodiment of step 53;

[0031] Figure 7 yes Figure 5 A flowchart of an embodiment of step 55;

[0032] Figure 8 This is a schematic flowchart of another embodiment of the blood oxygen detection method provided in this application;

[0033] Figure 9 This is a schematic diagram of an embodiment of the computer-readable storage medium provided in this application. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of this application.

[0035] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0036] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0037] The use of "applies to" or "configured to" in this application implies open and inclusive language, which does not exclude the applicability to or configuration to devices performing additional tasks or steps. Additionally, the use of "based on" implies openness and inclusivity, because processes, steps, calculations, or other actions "based on" one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0038] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0039] Understandably, the PGG signal comprises two parts: an AC value that modulates changes in arterial blood volume, and a stable DC value that does not modulate changes in arterial blood volume. Analyzing the ratio of AC to DC values ​​in red and infrared light can yield the SpO2 blood oxygen saturation level.

[0040] Ideally, the pulsating portion of arterial blood only contains the main components: oxyhemoglobin HbO2 and deoxyhemoglobin Hb. Calculating the proportion of HbO2 in these two hemoglobins allows us to determine the blood oxygen saturation value (SpO2). However, in reality, veins also pulsate, and after oxygen exchange with tissues, deoxyhemoglobin Hb becomes the main component, as shown in the following formula:

[0041]

[0042] C Hb An increase in this component will lead to a lower calculated SpO2. The more of this component measured by the PPG signal, the lower the calculated SpO2 will be. When it falls below the accurate blood oxygen value measured by standard equipment by 3 RMSE, it will be considered a false reading, resulting in pseudo-hypoxia. False hypoxia refers to the phenomenon where the calculated SpO2 result is lower because the PPG signal contains too much of the pulsatile component of venous blood Hb.

[0043] Different LED lights have different wavelengths, resulting in varying detection depths on the skin. Common light sources used in PPG measurement technology include green, red, and infrared light. Green light has a shorter wavelength and a shallower detection depth, making it suitable for detecting superficial blood vessel signals. Red and infrared light have deeper detection depths, and the tightness of the garment has little impact on the number of vessels detected. Green light has a shallow detection depth, so the number of vessels detected by green light is highly sensitive to the tightness of the garment. Specifically, comparing... Figure 1a and Figure 1b , Figure 1a This is a schematic diagram of the first depth detection in one embodiment. Figure 1b This is a schematic diagram of the second depth detection in one embodiment, as shown below. Figure 1a As shown, during normal wear, the skin on the wrist experiences a certain degree of pressure, becoming more translucent. The light emitted by the LED is then modulated by numerous blood vessels before being detected by the PD. Figure 1b As shown, when the wrist is worn loosely, the skin pressure decreases, the skin is less permeable, and fewer blood vessels are detected. Consequently, the AC amplitude of the green PPG signal decreases, and the PI is lower than when worn normally, even with minimal change in DC component. Based on this, this solution compensates for the detection of deeper red and infrared signals by utilizing the correlation between green light signal intensity and wearing tightness, thereby mitigating or even eliminating the pseudo-hypoxia effect when worn loosely.

[0044] Based on the above principles, the blood oxygen detection method of this application will be described through the following embodiments.

[0045] See Figure 2 , Figure 2 This is a flowchart illustrating an embodiment of the blood oxygen detection method provided in this application. The method includes:

[0046] Step 21: Determine the first blood perfusion index under the combined illumination of red and green light sources.

[0047] The perfusion index (PI) is the ratio of the AC value (pulsating component / alternating current component) to the DC value (steady component / direct current component). The AC and DC values ​​can be determined by the PPG signal.

[0048] Specifically, the light emitted by the red, green, or infrared light source is reflected or transmitted through human tissue, then collected by a photosensitive sensor and converted into an electrical signal (PPG signal). The PPG signal is then analyzed to determine the corresponding AC and DC values. Optionally, the red, green, or infrared light source can be an LED light source, and the photosensitive sensor can be a PD sensor.

[0049] Understandably, the light received by a PD sensor contains two components: a pulsating component (i.e., alternating current signal AC), which is the alternating component caused by the light absorption of pulsating arterial blood, and a stable component (i.e., direct current signal DC), which reflects the magnitude of light absorption caused by various non-pulsating tissues (such as epidermis, muscle, bone, and veins). Only the ratio of the amplitudes of the two wavelengths of the AC signal can reflect changes in blood oxygen saturation, while the two wavelengths of the DC signal can be used to calibrate the AC signal. Because the concentrations of HbO2 (oxygenated hemoglobin) and Hb (deoxygenated hemoglobin) in the blood change periodically with blood pulsation, their light absorption also changes pulsatingly, causing the intensity of the electrical signal output by the PD sensor to change periodically with blood pulsation.

[0050] Understandably, the PI value reflects pulsatile blood flow, that is, blood perfusion capacity. The greater the pulsatile blood flow, the more pulsatile components there are, and the larger the PI value. Therefore, the measurement site (skin, nails, bones, etc.) and the patient's own blood perfusion (arterial blood flow) will both affect the PI value. Since the sympathetic nervous system affects heart rate and arterial blood pressure (affecting pulsed arterial blood flow), the body's nervous regulatory system or mental state can also indirectly affect the PI value.

[0051] Alternatively, in one embodiment, as Figure 3 As shown, Figure 3 yes Figure 2A flowchart of an embodiment of step 21 is shown. Step 21 may specifically include:

[0052] Step 211: Drive the red and green light sources according to the current compensation coefficient.

[0053] Optionally, the method of this embodiment can be applied to wearable devices, such as... Figure 3 As shown, Figure 3 This is a schematic diagram of a wearable device 200 in one embodiment. The wearable device includes LEDs and a PD sensor, wherein the LEDs include red LEDs (R), green LEDs (G), and infrared LEDs (IR). In one embodiment, the red LEDs and infrared LEDs (IR) are arranged side by side with respect to the PD sensor, that is, the distances between the red LEDs and infrared LEDs and the PD sensor are approximately equal, while the green LEDs are closer to the PD sensor than the red LEDs.

[0054] The current compensation coefficient is obtained through prior measurement.

[0055] Optionally, in one embodiment, step 211 may include: obtaining a first current parameter and a current compensation coefficient; compensating the first current parameter using the current compensation coefficient to obtain a second current parameter; driving a red light source based on the first current parameter and driving a green light source based on the second current parameter.

[0056] Wherein, the first current parameter I R That is, the driving current value used to drive the red light source, the second current parameter I G That is, the driving current value used to drive the green light source, the first current parameter I R Second current parameter I G The following relationship must be satisfied:

[0057] I G =I R ×R 补偿

[0058] Among them, R 补偿 The current compensation coefficient (R) 补偿 The calculation method will be described in subsequent embodiments.

[0059] In this embodiment, when using the first current parameter I R While driving the red light source to turn on, it also uses the second current parameter I. G Turn on the green light source to allow the red and green light sources to work together.

[0060] Step 212: Collect the first pulse wave signal under the combined illumination of red and green light sources.

[0061] Among them, the first pulse wave signal PGG1 under the combined illumination of red and green light sources was collected.

[0062] Step 213: Determine the first blood flow perfusion index based on the first pulse wave signal and the red light blood flow perfusion compensation parameters.

[0063] Among them, the red light blood flow perfusion compensation parameters were obtained through pre-measurement.

[0064] Optionally, in one embodiment, step 113 may include: acquiring red light blood flow perfusion compensation parameters; determining an initial blood flow perfusion index based on a first pulse wave signal; and compensating the initial blood flow perfusion index using the red light blood flow perfusion compensation parameters to obtain a first blood flow perfusion index.

[0065] Specifically, the corresponding first pulsating component AC1 and first stable component DC1 are determined based on the first pulse wave signal PGG1, and then based on:

[0066]

[0067] Determine the initial blood perfusion index PI HUB Initial blood perfusion index PI HUB The perfusion index is calculated from the first pulse wave signal PGG1 acquired under simultaneous red and green light illumination, and then based on:

[0068] PI1 = PI HUB -PI 补偿

[0069] Determine the first blood perfusion index PI1, where PI 补偿 Red light perfusion compensation parameters (PI) 补偿 The calculation method will be introduced in subsequent embodiments. The first blood perfusion index PI1 is the initial blood perfusion index PI. HUB After red light blood perfusion compensation parameter PI 补偿 The revised blood perfusion index.

[0070] Step 22: Determine the second blood perfusion index under infrared light source irradiation.

[0071] Among them, based on the third current parameter I IR Driving the infrared light source, the third current parameter I IR The driving current value used to drive the infrared light source is used to collect the second pulse wave signal PGG2 under the illumination of the infrared light source, and the second blood perfusion index PI2 is determined based on the second pulse wave signal PGG2.

[0072] Specifically, the corresponding second pulsating component AC2 and second stable component DC2 are determined based on the second pulse wave signal PGG2, and then based on:

[0073]

[0074] The second blood flow perfusion index PI2 was determined. The second blood flow perfusion index PI2 is the blood flow perfusion index calculated from the second pulse wave signal PGG2 collected under infrared light source irradiation.

[0075] Understandably, this embodiment does not limit the execution order of steps 21 and 22.

[0076] Step 23: Determine the blood oxygen detection result based on the first blood perfusion index and the second blood perfusion index.

[0077] Step 23 may include: determining the blood perfusion ratio R based on the first blood perfusion index PI1 and the second blood perfusion index PI2; and then determining the blood oxygen detection result (such as the blood oxygen percentage value) based on the blood perfusion ratio R.

[0078] The blood oxygen detection method provided in this embodiment includes: determining a first blood perfusion index under the combined illumination of red and green light sources; and determining a second blood perfusion index under infrared light source illumination; and determining the blood oxygen detection result based on the first and second blood perfusion indices. Through this method, without increasing hardware costs, a blood oxygen measurement method is provided using three LEDs (red, infrared, and green). By using direct optical path compensation, a certain proportion of green light is activated simultaneously with the red light, using the green light as a compensation component to automatically adjust and reduce the increase in venous components, thereby reducing the influence of false hypoxia signals and improving measurement accuracy. Furthermore, since the red and green light are activated simultaneously, energy consumption can be reduced to a certain extent, increasing the battery life of wearable devices.

[0079] The above embodiments are mainly based on the characteristic that "green light is sensitive to the tightness of the garment." In addition, according to Lambert-Beer's law, the oxygenated hemoglobin capacity C... HbO2 Deoxyhemoglobin volume C Hb The absorption coefficients ∈ and the optical path length Δl of the two proteins are related to PI (perfusion rate) as follows:

[0080] PI = -(∈ HbO2 ×C HbO2 +∈ Hb ×C Hb )×Δl……(2)

[0081] Since the absorption coefficients of the two hemoglobins are different for different wavelengths of light, for example, if the wavelength of green light is 520nm, the wavelength of red light is 660nm, and the wavelength of infrared light is 940nm, the absorption coefficients of green light (520nm), red light (660nm), and infrared light (940nm) for HbO2 and Hb are shown in Table 1 below. Of course, the wavelengths of green light, red light, and infrared light can also be other values ​​within their corresponding wavelength ranges.

[0082] Table 1:

[0083] Absorption coefficient (L / (mol*cm)) Green light Red light Infrared HbO2 6 0.08 0.3 Hb 6 0.81 0.21

[0084] Table 1 shows that "the absorption coefficients of green light and infrared light for the two types of hemoglobin are similar." Utilizing this characteristic, combined with the aforementioned characteristic that "green light is sensitive to the tightness of the garment," the PI value of infrared light can be used to determine the optimal absorption coefficient. IR The theoretical value of PI for green light was derived. G理论 Based on the actual measured value of green light PI G and the theoretical value of PI G理论 The tightness or looseness of the relationship can then be measured.

[0085] The third characteristic is that infrared detection can penetrate deeper into tissues, and the density of tissue blood vessels can be assessed based on the infrared PI value, thus serving as a reference benchmark for the system's PI.

[0086] Based on these three characteristics, we can analyze the actual measured green light PI... G实际值 and theoretical PI G理论值 The ratio of the two values ​​is used to obtain the tightness coefficient R. 松紧 According to R 松紧 This allows us to determine the percentage of blood perfusion compensation R that will result from this level of tightness; based on the blood perfusion compensation ratio R and the current PI... R PI IR R can be obtained 调整 The ratio, thus obtaining PI 补偿 and PI 绿光补偿 .

[0087] The principle of green light compensation has been introduced above. The specific implementation methods are described below, such as... Figure 5 As shown, Figure 5 This is a flowchart illustrating another embodiment of the blood oxygen detection method provided in this application, the method comprising:

[0088] Step 51: Drive the red light source, green light source and infrared light source in sequence.

[0089] Understandably, the specific details of the red light source, green light source, and infrared light source in step 51 can be found in [reference needed]. Figure 4The diagram shows that the driving order of the red light source, green light source, and infrared light source is not restricted here.

[0090] Step 52: Collect red pulse wave signals under red light source illumination, green pulse wave signals under green light source illumination, and infrared pulse wave signals under infrared light source illumination.

[0091] The pulse wave signal is the PPG signal obtained by converting the optical signal collected by the PD sensor into an electrical signal. Specifically, the driving current of the red light source is I. R The corresponding red pulse wave signal is PPG. R Based on this PPG R The determined pulsation component is AC R The stable component is DC R The corresponding red light blood flow perfusion index is PI. R The driving current of the green light source is I. G The corresponding green pulse wave signal is PPG. G Based on this PPG G The determined pulsation component is AC G The stable component is DC G The corresponding green light blood flow perfusion index is PI. G The driving current of the infrared light source is I. IR The corresponding infrared pulse wave signal is PPG. IR Based on this PPG IR The determined pulsation component is AC IR The stable component is DC IR The corresponding infrared blood perfusion index is PI. IR .

[0092] Step 53: Determine the tightness coefficient based on the green light pulse wave signal and the infrared pulse wave signal.

[0093] Optionally, such as Figure 6 As shown, Figure 6 yes Figure 5 A flowchart illustrating an embodiment of step 53, which may include:

[0094] Step 531: Determine the green light blood flow perfusion index based on the green light pulse wave signal and the infrared blood flow perfusion index based on the infrared pulse wave signal.

[0095] Among them, the green light blood perfusion index is PI G The infrared blood perfusion index is PI IR .

[0096] Step 532: Determine the theoretical value of green light blood perfusion based on the infrared blood perfusion index.

[0097] The following table was obtained after consulting relevant materials:

[0098] Table 2:

[0099]

[0100]

[0101] Table 3:

[0102] hypoxia Arterial pulsation portion venous pulsation HbO2 content (umol) 350 0 Hb content (umol) 175 150 Percentage of venous pulsation component (%) 22

[0103] Table 4:

[0104] Ascorbic Includes venous pulsation (1 / 10000) Excluding venous pulsation (1 / 10000) PI change rate (%) Green light PI 243 189 22 Red light PI 15.267 5.061 67 Infrared PI 15.687 13.041 17

[0105] Table 5:

[0106] hypoxia Includes venous pulsation (1 / 10000) Excluding venous pulsation (1 / 10000) PI change rate (%) Green light PI 243 189 22 Red light PI 24.465 14.259 42 Infrared PI 14.553 11.907 18

[0107] As shown in Tables 2-5 above, under normoxic or hypoxic conditions, the PI change rate of green and red light follows the change in the proportion of venous pulsation, and the magnitudes of change are similar. Taking normoxic conditions as an example, when the proportion of venous pulsation is 22%, the PI change rate of green light is also 22%, while that of infrared light is slightly lower at 17% (from the perspective of absorption spectrum, the absorption coefficient of the two types of hemoglobin differs due to the selected wavelength of 940nm; if a wavelength of 805nm were selected, the change would be consistent). In other words, with a fixed total blood volume, changes in the ratio of oxygenated to deoxygenated hemoglobin in the blood do not affect the PI value of green light. G PI value for infrared IR The impact is also relatively small, with the infrared PI value being relatively small. IR It can characterize the change in blood volume at the test site and can be based on the PI of infrared radiation. IR Calculate the PI of a well-fitting device G理论 .

[0108] For example, substituting the absorption coefficients of green light and infrared light for hemoglobin and deoxyhemoglobin as 6, 6, 0.3, and 0.21, and the optical path lengths of the two structure-related light sources as 0.6 and 0.84, we can see that the absorption coefficients and optical path lengths are merely examples and can be obtained from the actual structural parameters required. The default deoxyhemoglobin to oxyhemoglobin volume ratio is 1:99, which can be calculated using the following formula for PI. G理论 :

[0109]

[0110]

[0111]

[0112] Among them, according to the infrared blood perfusion index PI IR Determine the theoretical value PI of green light blood perfusion G理论 Understandably, based on the green light compensation principle described above, the light absorption coefficients of green light and infrared light are close. Therefore, the infrared blood perfusion index PI can be considered... IR Theoretical value of green light blood perfusion PI G理论 The infrared perfusion index (PI) shows a linear relationship and does not require differentiation of hypoxia. IR Theoretical value of green light blood perfusion PI G理论 The correspondence can be tabulated based on the experimental data, and the specific relationship can be determined by looking up the table. Alternatively, the above formula (5) can also be used:

[0113]

[0114] The theoretical value PI of green light blood flow perfusion was calculated. G理论 This will not be elaborated upon here.

[0115] Step 533: Determine the tightness coefficient based on the green light blood flow perfusion index and the theoretical value of green light blood flow perfusion.

[0116] Specifically, the above formula (5) can be used:

[0117]

[0118] The tightness coefficient R is calculated. 松紧 .

[0119] Step 54: Determine the blood perfusion compensation ratio based on the tightness coefficient.

[0120] Combining this with Tables 4 and 5 above, the same 22% increase in venous pulsation was observed in red light PI under both normoxic and hypoxic conditions. R The proportion of impact varies, meaning the compensation ratio should also be inconsistent. Under normal oxygen conditions, the impact ratio is 67%, while under hypoxia, it decreases to 42%. The proportion of red light compensation needed needs to be calculated based on the blood perfusion compensation ratio caused by the tightness of the bandage and the current blood oxygenation status.

[0121] For example, red light takes ∈ HbO2 =0.08, ∈ Hb =0.81; where, ∈ HbO2 and ∈ Hb Related to the wavelength of the LED, it can be adjusted according to the wavelength of the selected LED. Let the HbO2 and Hb contents under good wear conditions be C1 and C2 respectively, and the perfusion rate be PI. 佩戴良好Let r1 be the proportion of Hb. With a loose fit, the total blood volume (C1+C2) is increased by venous pulsation, and the proportion of pulsation to the total (C1+C2) is denoted as R (perfusion compensation ratio). Let S1 be the HbO2 content and S2 be the Hb content under loose fit conditions, and PI be the perfusion rate. 松佩戴 ,but:

[0122]

[0123] Furthermore, we can obtain:

[0124]

[0125] The proportion of blood perfusion compensation R caused by the tightness of the garment will result in a corresponding proportion of PI that needs to be compensated. 调整 for:

[0126]

[0127] Furthermore, the formula for calculating blood oxygen and infrared PI are known. R The distribution density of blood vessels is characterized as being relatively insensitive to changes in Hb content. The following formulas can be used to obtain the blood perfusion compensation ratio R caused by the tightness of the garment and the compensation R required for existing red light PI measurements. 调整 Relationship:

[0128]

[0129] This allows us to obtain the required adjustment ratio R. 调整 The relationship between the blood perfusion compensation ratio R and the blood flow compensation ratio is as follows:

[0130]

[0131] The error originates from the PI above. IR松佩戴 and PI IR佩戴良好 Error and R 松紧 Is the correlation between the coefficient and the actual tightness causing the blood perfusion compensation ratio R accurate? The following discussion focuses on PI. IR松佩戴 Transformation to PI IR佩戴良好 The error caused by this.

[0132] Here, r1 and r2 represent the percentages of Hb worn well and loosely, respectively. PI 佩戴良好 and PI 松佩戴 Let PI values ​​be for a properly worn and loosely worn garment, respectively. Then:

[0133]

[0134]

[0135] As can be seen through PI松佩戴 PI is directly calculated from the blood perfusion compensation ratio R. 佩戴良好 =PI 松佩戴 / (1+R) ignores the influence of r2 and r1, resulting in errors. However, because the absorption coefficients of infrared HbO2 and Hb are similar, the error caused by their different absorption coefficients can be controlled within 3% by introducing a correction coefficient related to the tightness of the fit (the looser the fit, the larger the error). This is much smaller than the influence of fit on the red light PI value. Therefore, to simplify the calculation, it can be used to... IR松佩戴 PI is approximately obtained IR佩戴良好 The value of is obtained by fitting the relationship between the change of R and (30-9r2) / (30-9r1), resulting in (30-9r2) / (30-9r1)≈

[0136] The adjusted ratio R after correction (1-0.167R) 调整 The relationship between the tightness of the garment and the blood perfusion compensation ratio R is as follows:

[0137]

[0138] And R 松紧 There is a one-to-one correspondence between the blood perfusion compensation ratio R caused by venous pulsation due to tightness of the garment and the ratio R, which can be obtained from experimental data. There exists a maximum blood perfusion compensation ratio R. max (The value can be determined based on experimental data; 0.15 is used here.) Based on this ratio, R can be obtained. 调整max Based on the current blood perfusion compensation ratio R under the current R tension / relaxation conditions. 当前 R can be calculated 调整当前 Thus, the maximum PI compensation for red light is obtained as PI. 补偿 and PI used for green light compensation G补偿 (Used to calculate the driving current of the green light source to compensate for the red light):

[0139]

[0140] Understandably, based on the green light compensation principle described above, the tightness coefficient R... 松紧 There is a one-to-one correspondence between the blood perfusion compensation ratio R and the experimental data, which can be obtained by looking up a table to determine the maximum value of the blood perfusion compensation ratio R. max Maximum blood perfusion compensation ratio R max The maximum blood perfusion compensation ratio R can be obtained by looking up experimental data in a table. In one embodiment, the maximum value of R is... max A value of 0.15 can be used. Then, based on the maximum value R of the blood perfusion compensation ratio... max Determine the blood perfusion compensation ratio.

[0141] Optionally, the blood perfusion compensation ratio includes the maximum blood perfusion compensation ratio R. 调整max Current value of blood perfusion compensation ratio R 调整当前 Specifically, the above formula (13) can be used:

[0142]

[0143] Step 55: Determine the current compensation coefficient and red light blood perfusion compensation parameters based on the blood perfusion compensation ratio, red light pulse wave signal, and green light pulse wave signal.

[0144] Optionally, step 55 may include:

[0145] Red light blood perfusion compensation parameter PI R补偿 Calculation: The red light blood perfusion compensation parameters are determined based on the maximum blood perfusion compensation ratio.

[0146] Alternatively, the specific result can be calculated using the formula (14) above:

[0147] PI R补偿 =PI 松佩戴 ×R 调整max

[0148] Among them, PI R补偿 PI is the parameter for red light blood flow perfusion compensation. 松佩戴 R represents the red light perfusion index under loose wearing conditions. 调整max This represents the maximum blood perfusion compensation ratio.

[0149] Current compensation coefficient AC 补偿 The calculation is as follows: The current compensation coefficient is determined based on the maximum value of the blood perfusion compensation ratio, the current value of the blood perfusion compensation ratio, the red pulse wave signal, and the green pulse wave signal.

[0150] like Figure 7 As shown, Figure 7 yes Figure 5 A flowchart illustrating an embodiment of step 55, which may include:

[0151] Step 551: Determine the red light DC component based on the red light pulse wave signal, and determine the green light DC component and green light blood flow perfusion index based on the green light pulse wave signal.

[0152] Among them, according to the red pulse wave signal PPG R Determine the DC component of red light R According to the green pulse wave signal PPG G Determine the DC component of green light G and green light DC perfusion index PI G .

[0153] Step 552: Determine the green light blood perfusion compensation parameters based on the maximum value of the blood perfusion compensation ratio and the current value of the blood perfusion compensation ratio.

[0154] Alternatively, the specific result can be calculated using the formula (14) above:

[0155] PI G补偿 =PI 松佩戴 ×(R 调整max -R 调整当前 )

[0156] Among them, PI R补偿 PI is the parameter for green light blood flow perfusion compensation. 松佩戴 R represents the red light perfusion index under loose wearing conditions. 调整max R represents the maximum blood perfusion compensation ratio. 调整当前 This is the current value of the blood perfusion compensation ratio.

[0157] Step 553: Determine the AC compensation parameters based on the red light DC component and the green light blood flow perfusion compensation parameters.

[0158] The AC compensation parameters are determined using the following formula:

[0159] AC 补偿 =PI G补偿 ×DC R ;

[0160] Among them, AC 补偿 To exchange compensation parameters, PI G补偿 For green light blood flow perfusion compensation parameters, DC R This is the DC component of red light.

[0161] Step 554: Determine the current compensation coefficient based on the AC compensation parameters, the DC component of green light, and the green light blood flow perfusion index.

[0162] Optionally, step 554 may specifically include: obtaining the red light driving current I for driving the red light source. R And to obtain the green light driving current I that drives the green light source. G According to AC compensation parameters 补偿 Green light blood perfusion index (PI) G Green light DC component G and green light driving current I G Determine the green photocurrent compensation value I G补偿 The details are as follows:

[0163] The green photocurrent compensation value is determined using the following formula:

[0164] I G补偿 =AC 补偿 / PI G / DC G ×I G ;

[0165] Among them, I G补偿 This is the green photocurrent compensation value, AC 补偿 To exchange compensation parameters, PI G For green light blood flow perfusion index, DC G For the green light DC component, I G The current is driven by the green light.

[0166] Then, based on the green light current compensation value and the red light driving current, the current compensation coefficient is determined as follows:

[0167] R 补偿 =I G补偿 / I R ;

[0168] Among them, R 补偿 I is the current compensation coefficient. G补偿 I is the green photocurrent compensation value. R This is the current driven by the red light.

[0169] Understandably, Figures 5-7 The principles of each formula and calculation logic in the embodiments can be obtained from the green light compensation principle described above, and will not be repeated here.

[0170] See Figure 8 , Figure 8 This is a flowchart illustrating the third embodiment of the blood oxygen detection method provided in this application. The method includes:

[0171] Step 81: Detect the wearing status.

[0172] Step 82: In response to changes in the wearing status, determine the current compensation coefficient and the red light blood flow perfusion compensation parameters.

[0173] Optionally, in one embodiment, the blood oxygen detection device used in this blood oxygen detection method is a wearable device, such as a watch, and the wearing state refers to the watch's wearing status. Specifically, changes in the watch's wearability can be detected using built-in motion sensors (such as gravity sensors and accelerometers) and light sensors (such as infrared sensors). For example, the infrared sensor detects the distance between the watch and the human body (wrist surface). When this distance changes by more than a set distance threshold, it can be considered that the watch has fallen off, indicating a change in the wearing state, and requiring a re-determination of the current compensation coefficient and red light blood flow perfusion compensation parameters.

[0174] Understandably, in step 82, if it is determined that the wearing status has changed, the current compensation coefficient and the red light blood flow perfusion compensation parameter are determined, and then step 83 is executed; if it is determined that the wearing status has not changed, step 83 is executed directly.

[0175] Step 83: Drive the red and green light sources according to the current compensation coefficient.

[0176] Step 84: Collect the first pulse wave signal under the combined illumination of red and green light sources.

[0177] Step 85: Determine the first blood flow perfusion index based on the first pulse wave signal and the red light blood flow perfusion compensation parameters.

[0178] Step 86: Determine the second blood perfusion index under infrared light source irradiation.

[0179] Step 87: Determine the blood oxygen detection result based on the first blood perfusion index and the second blood perfusion index.

[0180] Steps 83-87 are similar to those in the above embodiments and will not be repeated here.

[0181] The blood oxygen detection method provided in this application includes: determining a first blood perfusion index under combined red and green light source illumination; and determining a second blood perfusion index under infrared light source illumination; and determining the blood oxygen detection result based on the first and second blood perfusion indices. Through this method, without increasing hardware costs, a blood oxygen measurement method is provided using three LEDs (red, infrared, and green). By employing direct optical path compensation, a certain proportion of green light is activated simultaneously with the red light, using the green light as a compensation component to automatically adjust and reduce the increase in venous components, thereby reducing the influence of false hypoxia signals and improving measurement accuracy. Furthermore, the current compensation coefficient and red light blood perfusion compensation parameters are remeasured in real time based on the wearer's status, ensuring data accuracy.

[0182] See Figure 9 , Figure 9 This is a schematic diagram of an embodiment of a computer-readable storage medium provided in this application. The computer-readable storage medium 900 stores program data 901, which, when executed by a processor, is used to implement the steps of the blood oxygen detection method in any of the above embodiments of the blood oxygen detection method.

[0183] The computer-readable storage medium 900 may be embodied in the form of a processing chip or a storage chip as described in the above embodiments, or it may be RAM or ROM integrated in the chip or in the chip's peripheral circuitry.

[0184] In the several embodiments provided in this application, it should be understood that the disclosed methods and devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of modules or units is merely 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 coefficient, or some features may be ignored or not executed.

[0185] 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, depending on actual needs.

[0186] 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.

[0187] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method of blood oxygen detection, the method comprising: The blood oxygen detection method comprises: determining a first blood perfusion index under irradiation of a red light source and a green light source together; and determining a second blood perfusion index under irradiation of an infrared light source; determining a blood oxygen detection result according to the first blood perfusion index and the second blood perfusion index; The method further comprises: sequentially driving the red light source, the green light source and the infrared light source; acquiring a red light pulse wave signal under irradiation of the red light source, acquiring a green light pulse wave signal under irradiation of the green light source, and acquiring an infrared pulse wave signal under irradiation of the infrared light source; determining a tightness coefficient according to the green light pulse wave signal and the infrared pulse wave signal; determining a blood perfusion compensation ratio according to the tightness coefficient; determining the current compensation coefficient and the red light blood perfusion compensation parameter according to the blood perfusion compensation ratio, the red light pulse wave signal and the green light pulse wave signal.

2. The blood oxygen detection method according to claim 1, wherein the driving of the red light source and the green light source according to the current compensation coefficient comprises: obtaining a first current parameter and a current compensation coefficient; compensating the first current parameter by using the current compensation coefficient to obtain a second current parameter; driving the red light source based on the first current parameter and driving the green light source based on the second current parameter.

3. The blood oxygen detection method according to claim 1, wherein the determining of the first blood perfusion index according to the first pulse wave signal and the red light blood perfusion compensation parameter comprises: obtaining a red light blood perfusion compensation parameter; determining an initial blood perfusion index according to the first pulse wave signal; compensating the initial blood perfusion index by using the red light blood perfusion compensation parameter to obtain the first blood perfusion index.

4. The blood oxygen detection method according to claim 1, wherein the determining of the tightness coefficient according to the green light pulse wave signal and the infrared pulse wave signal comprises: determining a green light blood perfusion index according to the green light pulse wave signal and determining an infrared blood perfusion index according to the infrared pulse wave signal; determining a green light blood perfusion theoretical value according to the infrared blood perfusion index; determining the tightness coefficient according to the green light blood perfusion index and the green light blood perfusion theoretical value.

5. The blood oxygen detection method according to claim 1, wherein the determining of the blood perfusion compensation ratio according to the tightness coefficient comprises: determining a blood perfusion compensation ratio maximum value corresponding to a tightness coefficient maximum value; and determining a blood perfusion compensation ratio current value corresponding to a tightness coefficient current value; the determining of the current compensation coefficient and the red light blood perfusion compensation parameter according to the blood perfusion compensation ratio, the red light pulse wave signal and the green light pulse wave signal comprises: ​ ​ ​ ​ determine a red blood perfusion compensation parameter according to the maximum blood perfusion compensation ratio; determine the current compensation coefficient according to the maximum blood perfusion compensation ratio, the current blood perfusion compensation ratio, the red pulse wave signal and the green pulse wave signal. 6.The blood oxygen detection method of claim 5, wherein determining the red blood perfusion compensation parameter according to the maximum blood perfusion compensation ratio comprises: determining the red blood perfusion compensation parameter according to the following formula: ； wherein, is a red light perfusion compensation parameter, is a red light perfusion index in the case of loose wearing, is a perfusion compensation ratio maximum value. 7.The blood oxygen detection method of claim 5, wherein determining the current compensation coefficient according to the maximum blood perfusion compensation ratio, the current blood perfusion compensation ratio, the red pulse wave signal and the green pulse wave signal comprises: determining a red direct current component according to the red pulse wave signal, and determining a green direct current component and a green blood perfusion index according to the green pulse wave signal; determining a green blood perfusion compensation parameter according to the maximum blood perfusion compensation ratio and the current blood perfusion compensation ratio; determining an alternating current compensation parameter according to the red direct current component and the green blood perfusion compensation parameter; determining the current compensation coefficient according to the alternating current compensation parameter, the green direct current component and the green blood perfusion index. 8.The blood oxygen detection method of claim 7, wherein determining the green blood perfusion compensation parameter according to the maximum blood perfusion compensation ratio and the current blood perfusion compensation ratio comprises: determining the green blood perfusion compensation parameter according to the following formula: ； wherein, is a green light perfusion compensation parameter, is a red light perfusion index in case of loose wearing, is a perfusion compensation ratio maximum value, is a perfusion compensation ratio current value. 9.The blood oxygen detection method of claim 7, wherein determining the alternating current compensation parameter according to the red direct current component and the green blood perfusion compensation parameter comprises: determining the alternating current compensation parameter according to the following formula: ； wherein, is an AC compensation parameter, is a green light perfusion compensation parameter, is a red light direct current component. 10.The blood oxygen detection method of claim 7, wherein determining the current compensation coefficient according to the alternating current compensation parameter, the green direct current component and the green blood perfusion index comprises: obtaining a red driving current for driving the red light source, and obtaining a green driving current for driving the green light source; determining a green current compensation value according to the alternating current compensation parameter, the green blood perfusion index, the green direct current component and the green driving current; determining the current compensation coefficient according to the green current compensation value and the red driving current. 11.The blood oxygen detection method of claim 10, wherein determining the green current compensation value according to the alternating current compensation parameter, the green blood perfusion index, the green direct current component and the green driving current comprises: determining the green current compensation value according to the following formula: ； wherein, is a green light current compensation value, is an AC compensation parameter, is a green light blood perfusion index, is a green light DC component, is a green light drive current. 12.The blood oxygen detection method of claim 10, wherein determining the current compensation coefficient according to the green current compensation value and the red driving current comprises: determining the current compensation coefficient according to the following formula: ； wherein, is a current compensation factor, is a green light current compensation value, is a red light drive current. 13.The blood oxygen detection method of claim 1, wherein the method further comprises: detect a wearing state; in response to a change in the wearing state, determine the current compensation coefficient and the red light blood perfusion compensation parameter.

14. The blood oxygen detection method according to claim 1, wherein the determining a blood oxygen detection result according to the first blood perfusion index and the second blood perfusion index comprises: determining a blood perfusion ratio according to the first blood perfusion index and the second blood perfusion index; determining the blood oxygen detection result according to the blood perfusion ratio. The blood oxygen detection device comprises:

15. A blood oxygen detection apparatus, characterized by comprising: a red light source, a green light source and an infrared light source; a light sensor; a controller connected to the red light source, the green light source, the infrared light source and the light sensor, the controller being configured to execute the blood oxygen detection method according to any one of claims 1-14. The computer readable storage medium stores program data, and the program data, when executed by the processor, is configured to implement the blood oxygen detection method according to any one of claims 1-14.

16. A computer-readable storage medium, characterized in that, ​

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