Patent Description:
Blood oxygen saturation (oxygen saturation, SpO2) is a concentration of blood oxygen in blood. The blood oxygen saturation is an important physiological parameter of respiratory circulation and describes an ability of the blood to carry and deliver oxygen. A metabolism process of a human body is a biological oxidation process, and oxygen required in the metabolism process enters the blood of the human body through a respiratory system. The oxygen entering the blood of the human body and deoxyhemoglobin (hemoglobin, Hb) in red blood cells are combined to form oxyhemoglobin HbO2, and then the oxyhemoglobin is delivered to cells of various parts of the human body. SpO2 is a percentage of HbO2 in the blood to a total hemoglobin capacity. In other words, SpO2 = HbO2/(HbO2 + Hb) x <NUM>%. Usually, the percentage is about <NUM>%.

Currently, in some pulse blood oxygen detection, because blood vessels are sparsely distributed on a wrist, and on a surface layer, many veins are distributed and a pulse blood oxygen signal is relatively weak, interference caused by the veins cannot be ignored in data collected by using a single red light channel and an infrared light channel. Consequently, a signal-to-noise ratio of the data is relatively low. In addition, it is sensitive to a relative motion between skin and a sensor when one detection point is used for measurement. Therefore, this easily leads to interference caused by the motion.

<CIT> describes a blood oxygen measurement device which comprises a light emitting device, a light detecting device and a signal processing circuit, wherein the light emitting device is arranged on one side of an object to be detected and is used for emitting first wavelength light and second wavelength light, the light detecting device is arranged on the other side of the detected object relative to the light emitting device and comprises a first narrow-band light detector and a second narrow-band light detector, the first narrow-band light detector is used for receiving transmission light of the first wavelength light transmitting through the detected object and converting the transmission light into an electric signal corresponding to the first wavelength light, the second narrow-band light detector is used for receiving transmission light of the second wavelength light transmitting through the detected object and converting the transmission light into an electric signal corresponding to the second wavelength light, and the signal processing circuit is respectively coupled to an output end of the first narrow-band detector and an output end of a second narrow-band light detector and calculates oxyhemoglobin saturation. The blood oxygen measurement device effectively suppresses environment light, and meanwhile provides possibilities for improving capacities of the blood oxygen measurement device in terms of suppression of movement interference of a measured object.

<CIT> describes a detecting method, device and equipment. The detecting equipment comprises light source equipment, an optical detector and an acceleration sensor. The method comprises the steps that pulse oximeter signals obtained after a plurality of pieces of detection light emitted by the optical detector on the light source equipment pass through the detected tissue are acquired; heart rate detection waves carrying interference signals are subjected to filtering processing with acceleration signals as the standard; a dynamic heart rate value and a reference signal are obtained according to the heart rate detection waves; blood oxygen detection waves are subjected to effective section extraction according to the reference signal; the blood oxygen detection waves are calculated through a preset algorithm, and a ratio value R is obtained; the blood oxygen saturability is obtained according to the ratio value R. According to the detecting scheme, the interference signals introduced due to motion are filtered out to avoid the influence of motion on the detection result. The heat rate detection waves are adopted as the reference signal to carry out effective section extraction on the blood oxygen detection waves, and the defect that due to the fact that the blood oxygen detection waves are weak in interference resisting capacity, bad influence is caused to the detection result is avoided.

<CIT> describes a pulse oximeter device including a first light emitting element that emits red light, a second light emitting element that emits green light or IR light; and a sensor element that detects red and green (or IR) light and that outputs signals representing detected red and green (or IR) light. The pulse oximeter device further includes a flexible substrate, wherein the first light emitting element, the second light emitting element and the sensor element are formed on the flexible substrate. The sensor element is configured to detect the emitted red and green light transmitted through tissue containing blood, and in certain aspects, the sensor element is configured to detect the emitted red and green (or IR) light reflected by tissue containing blood. A signal processing element (e.g., a processor) receives and processes the signals representing detected red and green (or IR) light output by the sensor element to produce signals representing blood oxygenation content.

<CIT> describes a signal processor which acquires a first signal, including a first primary signal portion and a first secondary signal portion, and a second signal, including a second primary signal portion and a second secondary signal portion, wherein the first and second primary signal portions are correlated. The signals may be acquired by propagating energy through a medium and measuring an attenuated signal after transmission or reflection. Alternatively, the signals may be acquired by measuring energy generated by the medium. A processor generates a primary or secondary reference signal which is a combination, respectively, of only the primary or secondary signal portions. The secondary reference signal is then used to remove the secondary portion of each of the first and second measured signals via a correlation canceler, such as an adaptive noise canceler, preferably of the joint process estimator type. The primary reference signal is used to remove the primary portion of each of the first and second measured signals via a correlation canceler. The processor may be employed in conjunction with a correlation canceler in physiological monitors wherein the known properties of energy attenuation through a medium are used to determine physiological characteristics of the medium. Many physiological conditions, such as the pulse, or blood pressure of a patient or the concentration of a constituent in a medium, can be determined from the primary or secondary portions of the signal after other signal portion is removed.

<CIT> describes obtaining cardiovascular parameters using arterioles related transient time. In case the signal from larger blood vessels is measured geometrically relatively far from such a signal from smaller, arteriole-like blood vessels, said measured time difference may be evaluated by several ways in order to separate a PWTT component of time differences, obtained from said measured signals, from transient time component, including information about changes of diameter in arteriole-like vessels. It also may be effective defining more correctly the role of blood viscosity in monitored vascular condition of patient.

Embodiments of this application provide a blood oxygen detection method and apparatus. Alternating current/direct current decomposition is performed on red light signals and infrared signals collected at a plurality of collection points, an alternating current part is separated into a plurality of independent components by using an independent component analysis algorithm, and then correlation is performed between each independent component and a green light signal. In this way, interference of venous blood flows and capillaries can be effectively eliminated, a disadvantage of a low signal-to-noise ratio is made up, and an accuracy of a blood oxygen measurement on a wrist is increased.

According to a first aspect, a blood oxygen detection method is provided, as set out in claim <NUM>.

In a possible implementation, the determining red light direct current data and a component signal of a red light alternating current signal based on the at least two red light signals; and determining infrared direct current data and a component signal of an infrared alternating current signal based on the at least two infrared signals includes: determining at least two red light direct current signals and at least two red light alternating current signals based on the at least two red light signals; determining the red light direct current data based on the at least two red light direct current signals; determining at least two infrared direct current signals and at least two infrared alternating current signals based on the at least two infrared signals; determining the infrared direct current data based on the at least two infrared direct current signals; and determining the component signal of the red light alternating current signal based on the at least two red light alternating current signals, and determining the component signal of the infrared alternating current signal based on the at least two infrared alternating current signals.

In a possible implementation, the determining the component signal of the red light alternating current signal based on the at least two red light alternating current signals, and determining the component signal of the infrared alternating current signal based on the at least two infrared alternating current signals includes: separating at least one component signal of the at least two red light alternating current signals by using an independent component analysis algorithm or a principal component analysis algorithm, to obtain at least one component signal of the red light alternating current signal, where the at least one component signal of the red light alternating current signal includes an arterial signal; and separating at least one component signal of the at least two infrared alternating current signals by using the independent component analysis algorithm or the principal component analysis algorithm, to obtain at least one component signal of the infrared alternating current signal, where the at least one component signal of the infrared alternating current signal includes an arterial signal.

In a possible implementation, the determining red light alternating current data based on the component signal of the red light alternating current signal and the green light signal; and determining infrared alternating current data based on the component signal of the infrared alternating current signal and the green light signal includes: performing filtering processing on the green light signal; and determining the red light alternating current data based on the component signal of the red light alternating current signal and a green light signal obtained after the filtering processing, and determining the infrared alternating current data based on the component signal of the infrared alternating current signal and the green light signal obtained after the filtering processing.

In a possible implementation, the determining red light alternating current data based on the component signal of the red light alternating current signal and the green light signal; and determining infrared alternating current data based on the component signal of the infrared alternating current signal and the green light signal includes: performing comparison based on the at least one component signal of the red light alternating current signal and the green light signal, and determining that data corresponding to at least one component signal, of the red light alternating current signal, closest to the green light signal is the red light alternating current data; and performing comparison based on the at least one component signal of the infrared alternating current signal and the green light signal, and determining that data corresponding to at least one component signal, of the infrared alternating current signal, closest to the green light signal is the infrared alternating current data.

In a possible implementation, the red light direct current data is an average value, a maximum value, a minimum value, or a median of the at least two red light direct current signals; and the infrared direct current data is an average value, a maximum value, a minimum value, or a median of the at least two infrared direct current signals.

In a possible implementation, the determining blood oxygen saturation based on the red light direct current data, the red light alternating current data, the infrared direct current data, and the infrared alternating current data includes: determining pulse blood oxygen based on the red light direct current data, the red light alternating current data, the infrared direct current data, and the infrared alternating current data; and querying a pre-configured comparison table based on the pulse blood oxygen, to determine the blood oxygen saturation.

According to a second aspect, a blood oxygen detection apparatus is provided as set out in claim <NUM>.

In a possible implementation, the processor is further configured to: determine at least two red light direct current signals and at least two red light alternating current signals based on the at least two red light signals; determine the red light direct current data based on the at least two red light direct current signals; determine at least two infrared direct current signals and at least two infrared alternating current signals based on the at least two infrared signals; determine the infrared direct current data based on the at least two infrared direct current signals; determine the component signal of the red light alternating current signal based on the at least two red light alternating current signals; and determine the component signal of the infrared alternating current signal based on the at least two infrared alternating current signals.

In a possible implementation, the processor is further configured to: separate at least one component signal of the at least two red light alternating current signals by using an independent component analysis algorithm or a principal component analysis algorithm, to obtain at least one component signal of the red light alternating current signal, where the at least one component signal of the red light alternating current signal includes an arterial signal; and separate at least one component signal of the at least two infrared alternating current signals by using the independent component analysis algorithm or the principal component analysis algorithm, to obtain at least one component signal of the infrared alternating current signal, where the at least one component signal of the infrared alternating current signal includes an arterial signal.

In a possible implementation, the processor is further configured to: perform filtering processing on the green light signal; determine the red light alternating current data based on the component signal of the red light alternating current signal and a green light signal obtained after the filtering processing; and determine the infrared alternating current data based on the component signal of the infrared alternating current signal and the green light signal obtained after the filtering processing.

In a possible implementation, the processor is further configured to: perform comparison based on the at least one component signal of the red light alternating current signal and the green light signal, and determine that data corresponding to at least one component signal, of the red light alternating current signal, closest to the green light signal is the red light alternating current data; and perform comparison based on the at least one component signal of the infrared alternating current signal and the green light signal, and determine that data corresponding to at least one component signal, of the infrared alternating current signal, closest to the green light signal is the infrared alternating current data.

In a possible implementation, the red light direct current data is an average value, a maximum value, a minimum value, or a median of the at least two red light direct current signals. The infrared direct current data is an average value, a maximum value, a minimum value, or a median of the at least two infrared direct current signals.

In a possible implementation, the processor is further configured to: determine pulse blood oxygen based on the red light direct current data, the red light alternating current data, the infrared direct current data, and the infrared alternating current data; and query a pre-configured comparison table based on the pulse blood oxygen, to determine the blood oxygen saturation.

This application discloses a blood oxygen detection method and apparatus. More information is collected by using a plurality of measurement points, collected alternating current information is separated by using an independent component algorithm, and denoising is performed by using a green light signal, so that interference caused by venous blood flows, capillaries, and the like can be eliminated, a disadvantage of a low signal-to-noise ratio is made up, and accuracy of blood oxygen measurement on a wrist is increased.

This application is applied to wrist blood oxygen detection. Hemoglobin has different absorption rates for red light and infrared light. HbO2 absorbs more near-infrared light (infrared radiation, IR), and a wavelength of the IR is usually about <NUM>. Hb absorbs more red light, and a wavelength of the red light is usually about <NUM>. The red light and the infrared light are radiated into human tissue at the same time. Because blood flows of veins and other body tissue are relatively constant, absorption of light can be approximately considered as a fixed value. Arteries periodically expand with a pulse, and therefore a total blood volume per unit volume changes periodically. Therefore, absorption of the red light and infrared light by the arteries changes periodically with the pulse.

Some existing blood oxygen detection apparatuses use a finger clip type, and a finger of a measured person is put into a pulse oximeter of a finger clip type for measurement. As shown in <FIG>, in this solution, because the finger of the measured person needs to be clipped by the oximeter, the oximeter seriously interferes with a movement of the finger. In addition, it is more likely to cause discomfort when the finger is clipped for a long time. There are also some blood oxygen detection apparatuses using wrist-type single-channel measurement. A single-channel means that a signal is collected by using a single detection point. As shown in <FIG>, <NUM> is a red light sensor, and <NUM> is an infrared sensor. Pulse blood oxygen is detected by wearing the oximeter on the wrist. However, because blood vessels are sparsely distributed on the wrist and many veins are distributed on a surface layer, a pulse blood oxygen signal is relatively weak. Interference caused by the veins cannot be ignored in data collected by a single red light and infrared sensor. Consequently, a signal-to-noise ratio of the data is relatively low. In addition, it is sensitive to a relative motion between skin and a sensor when a single detection point is used for measurement. Therefore, this easily leads to interference caused by the motion.

To resolve the problem in the foregoing technology, in a detection method in this application, information about a plurality of detected parts is collected, and collected red light and infrared signals are divided into a red light alternating current signal, an infrared alternating current signal, a red light direct current signal, and an infrared direct current signal. Because signals collected by the sensor are a large quantity of original signals, data that can best reflect a current blood oxygen status needs to be extracted from the collected original signals. Therefore, in this application, red light alternating current data and infrared alternating current data are determined from the red light alternating current signal and the infrared alternating current signal through a correlation analysis with a green light signal. In addition, red light direct current data and infrared direct current data are determined by using the red light direct current signal and the infrared direct current signal. The red light direct current data in this application may be an average value, a maximum value, a minimum value, a median, or the like of a plurality of red light direct current signals. The infrared direct current data in this application may be an average value, a maximum value, a minimum value, a median, or the like of a plurality of infrared direct current signals. A green light signal is used to perform denoising on the red light alternating current data and the infrared alternating current data, so that interference caused by venous blood flows, capillaries, and the like can be eliminated. Finally, red light alternating current data, infrared alternating current data, red light direct current data, and infrared direct current data that are obtained after the denoising are used to calculate blood oxygen saturation. A disadvantage of a low signal-to-noise ratio is made up and accuracy of a blood oxygen measurement on the wrist is increased.

<FIG> is a flowchart of a blood oxygen detection method according to an embodiment of this application.

S201: Obtain at least two red light signals, at least two infrared signals, and a green light signal.

A signal of a measured user is collected by using at least two red light sensors, at least two infrared sensors, and a green light sensor. In an example, one detection point may include one red light sensor and one infrared sensor. In an embodiment, two detection points may be included, and each detection point obtains one red light signal and one infrared signal. In addition, a green light detection point is further included, and is configured to obtain a green light signal.

S202: Determine red light direct current data and a component signal of a red light alternating current signal based on the at least two red light signals; and determine infrared direct current data and a component signal of an infrared alternating current signal based on the at least two infrared signals, where the component signal includes an arterial signal.

Alternating current/direct current separation is performed on the at least two collected red light signals, to obtain the red light direct current data and the component signal of the red light alternating current signal. In addition, alternating current/direct current decomposition is performed on the at least two collected infrared signals, to obtain the infrared direct current data and the component signal of the infrared alternating current signal. In an example, the component signal includes the arterial signal. In another example, the component signal may alternatively include a capillary signal, another noise signal, or the like.

S203: Determine red light alternating current data based on the component signal of the red light alternating current signal and the green light signal, and determine infrared alternating current data based on the component signal of the infrared alternating current signal and the green light signal.

Compared with red light, green light can be absorbed by oxyhemoglobin and deoxyhemoglobin, a signal obtained by using the green light as a light source is better, and a signal-to-noise ratio is also better than that of another light source. Therefore, in this application, the green light is used for measurement, and is used as reference data of a pulse signal. In an example, there are a plurality of component signals, including a pulse signal. The green light signal is used to select the pulse signal from the plurality of component signals as alternating current data, so as to determine the red light alternating current data and the infrared alternating current data.

S204: Determine blood oxygen saturation based on the red light direct current data, the red light alternating current data, the infrared direct current data, and the infrared alternating current data.

In this application, more information is collected by using a plurality of measurement points, then collected alternating current information is separated by using an independent component analysis algorithm, and denoising is performed by using the green light signal, so that interference caused by venous blood flows, capillaries, and the like can be eliminated, a disadvantage of a low signal-to-noise ratio is made up, and accuracy of a blood oxygen measurement on a wrist is increased.

The following more specifically describes the technical solutions of this application with reference to embodiments. <FIG> is a flowchart of another blood oxygen detection method according to an embodiment of this application.

As shown in <FIG>, after S201, the method further includes the following steps.

S301: Determine at least two red light direct current signals and at least two red light alternating current signals based on the at least two red light signals.

Alternating current/direct current separation is performed on red light signals received by a plurality of detection points, to obtain a plurality of red light direct current signals and a plurality of red light alternating current signals. In an example, alternating current/direct current separation is performed on a red light signal received at each detection point, and a red light direct current signal and a red light alternating current signal are obtained at each detection point. In another example, detection may be further performed on each detection point a plurality of times. In each time of detection, alternating current/direct current separation is performed on a red light signal received at each detection point, and a red light direct current signal and a red light alternating current signal are obtained at each detection point.

S302: Determine red light direct current data based on the at least two red light direct current signals.

In an example, one piece of red light direct current data is determined based on a plurality of red light direct current signals determined by a plurality of detection points. In another example, one piece of red light direct current data may be determined based on a plurality of red light direct current signals determined through a plurality of times of measurement at each detection point. The red light direct current data may be an average value, a maximum value, a minimum value, a median, or the like of the plurality of red light direct current signals. A person skilled in the art should note that the direct current data reflects a status of deoxyhemoglobin in a venous blood vessel. Because a blood flow in the venous blood vessel is relatively constant, a plurality of direct current signals may be combined into the red light direct current data, and any equivalent variation or replacement shall fall within the protection scope of this application.

S303: Determine at least two infrared direct current signals and at least two infrared alternating current signals based on the at least two infrared signals.

Alternating current/direct current separation is performed on infrared signals received by a plurality of detection points, to obtain a plurality of infrared direct current signals and a plurality of infrared alternating current signals. In an example, alternating current/direct current separation is performed on an infrared signal received at each detection point, and an infrared direct current signal and an infrared alternating current signal are obtained at each detection point. In another example, detection may be performed on each detection point a plurality of times. In each time of detection, alternating current/direct current separation is performed on an infrared signal received at each detection point, and an infrared direct current signal and an infrared alternating current signal are obtained at each detection point.

S304: Determine the infrared direct current data based on the at least two infrared direct current signals.

In an example, one piece of infrared direct current data is determined based on a plurality of infrared direct current signals determined by a plurality of detection points. In another example, one piece of infrared direct current data may be determined based on a plurality of infrared direct current signals determined through a plurality of times of measurement at each detection point. The infrared direct current data may be an average value, a maximum value, a minimum value, a median, or the like of the plurality of infrared direct current signals. A person skilled in the art should note that the direct current data reflects a status of oxyhemoglobin in a venous blood vessel. Because a blood flow in the venous blood vessel is relatively constant, a plurality of direct current signals may be combined into the red light direct current data, and any equivalent variation or replacement shall fall within the protection scope of this application.

S305: Determine a component signal of the red light alternating current signal based on the at least two red light alternating current signals; and determine a component signal of the infrared alternating current signal based on the at least two infrared alternating current signals.

In an example, a plurality of component signals in the plurality of red light alternating current signals are separated by using the independent component analysis algorithm, to obtain the plurality of component signals of the red light alternating current signals, where the plurality of component signals of the red light alternating current signals include an arterial signal. In addition, a plurality of component signals of the plurality of infrared alternating current signals are separated by using the independent component analysis algorithm, to obtain the plurality of component signals of the infrared alternating current signals, where the plurality of component signals of the infrared alternating current signals include an arterial signal. The plurality of component signals are independent of each other. In other words, the plurality of component signals are irrelevant to each other. In an example, n may be set to a quantity of red light alternating current signals, where n is greater than or equal to <NUM>, and m is set to a quantity of component signals of the red light alternating current signals, where m is greater than or equal to <NUM>. In an embodiment, if n = m, it means that a quantity of red light alternating current signals is equal to a quantity of component signals separated from the red light alternating current signals. The component signals include an arterial signal. Similarly, component signals of the plurality of infrared alternating current signals may be determined. In another example, a plurality of component signals in the plurality of red light/infrared alternating current signals may be separated by using a principal component analysis algorithm, to obtain the plurality of component signals of the red light/infrared alternating current signals. A person skilled in the art should note that, for a method for separating a plurality of component signals from a plurality of alternating current signals, any other equivalent variation or replacement that can be easily figured out shall fall within the protection scope of this application.

S306: Determine red light alternating current data based on the component signal of the red light alternating current signal and a green light signal obtained after filtering processing, and determine infrared alternating current data based on the component signal of the infrared alternating current signal and the green light signal obtained after the filtering processing.

In an example, pre-processing of filtering and denoising is performed on the collected green light signal. Then, a green light signal obtained after the denoising is used as reference data of a pulse signal. The pulse signal is selected from the plurality of determined component signals of the red light alternating current signals, and the pulse signal is used as the red light alternating current data. In an example, linear correlation may be used to determine a correlation degree between the plurality of component signals of the red light alternating current signals and the green light signal obtained after the filtering processing. The correlation degree may be understood as a similarity degree. Then, a component signal that is of a red light alternating current signal and that is most closely correlated with the green light signal obtained after the filtering processing is determined as the red light alternating current data. Likewise, a component signal that is of an infrared alternating current signal and that is most closely correlated with the green light signal obtained after the filtering processing is determined as the infrared alternating current data.

S307: Determine pulse blood oxygen based on the red light direct current data, the red light alternating current data, the infrared direct current data, and the infrared alternating current data.

In an example, after the red light direct current data, the red light alternating current data, the infrared direct current data, and the infrared alternating current data are determined, the pulse blood oxygen may be determined according to a formula <MAT>. A value of R represents a concentration proportional relationship between Hb and HbO2 in blood, Redac is the red light alternating current data, Reddc is the red light direct current data, IRac is the infrared alternating current data, and IRdc is the infrared direct current data.

S308: Query a pre-configured comparison table based on the pulse blood oxygen to determine blood oxygen saturation.

An SpO2 value corresponding to a pulse blood oxygen value is queried based on the pre-configured comparison table of pulse blood oxygen and SpO2.

In this application, more information is collected by using a plurality of measurement points, then collected alternating current information is separated by using the independent component analysis algorithm, and denoising is performed by using the green light signal, so that interference caused by venous blood flows, capillaries, and the like can be eliminated, a disadvantage of a low signal-to-noise ratio is made up, and accuracy of a blood oxygen measurement on a wrist is increased.

<FIG> is a schematic diagram of a blood oxygen detection apparatus according to an embodiment of this application.

As shown in <FIG>, a blood oxygen detection apparatus <NUM> is provided. The apparatus <NUM> includes: a collection module <NUM>, configured to obtain at least two red light signals, at least two infrared signals, and a green light signal; an alternating current/direct current decomposition module <NUM>, configured to: determine red light direct current data and a component signal of a red light alternating current signal based on the at least two red light signals, and determine infrared direct current data and a component signal of an infrared alternating current signal based on the at least two infrared signals, where the component signal includes an arterial signal; a component analysis module <NUM>, configured to: determine red light alternating current data based on the component signal of the red light alternating current signal and the green light signal, and determine infrared alternating current data based on the component signal of the infrared alternating current signal and the green light signal; and a blood oxygen conversion module <NUM>, configured to determine blood oxygen saturation based on the red light direct current data, the red light alternating current data, the infrared direct current data, and the infrared alternating current data.

In a possible implementation, the alternating current/direct current decomposition module <NUM> is further configured to: determine at least two red light direct current signals and at least two red light alternating current signals based on the at least two red light signals; determine the red light direct current data based on the at least two red light direct current signals; determine at least two infrared direct current signals and at least two infrared alternating current signals based on the at least two infrared signals; determine the infrared direct current data based on the at least two infrared direct current signals; determine the component signal of the red light alternating current signal based on the at least two red light alternating current signals; and determine the component signal of the infrared alternating current signal based on the at least two infrared alternating current signals. In another example, a red light direct current component and an infrared direct current component may alternatively be determined in another independent module.

In a possible implementation, the component analysis module <NUM> is further configured to: separate at least one component signal of the at least two red light alternating current signals by using an independent component analysis algorithm or a principal component analysis algorithm, to obtain at least one component signal of the red light alternating current signal, where the at least one component signal of the red light alternating current signal includes an arterial signal; and separate at least one component signal of the at least two infrared alternating current signals by using the independent component analysis algorithm or the principal component analysis algorithm, to obtain at least one component signal of the infrared alternating current signal, where the at least one component signal of the infrared alternating current signal includes an arterial signal.

In a possible implementation, the apparatus <NUM> further includes a preprocessing module <NUM>. The preprocessing module <NUM> is configured to perform filtering processing on the green light signal. In an example, the preprocessing module may perform filtering processing on the green light signal by using a filter. A person skilled in the art should note that the filter is merely a possible implementation, and any equivalent replacement falls within the protection scope of this application. A specific filter to be used is not limited herein. The component analysis module <NUM> is further configured to: determine the red light alternating current data based on the component signal of the red light alternating current signal and the green light signal obtained after the filtering processing, and determine the infrared alternating current data based on the component signal of the infrared alternating current signal and the green light signal obtained after the filtering processing.

In a possible implementation, the component analysis module <NUM> is further configured to: perform comparison based on the at least one component signal of the red light alternating current signal and the green light signal, and determine that data corresponding to at least one component signal, of the red light alternating current signal, closest to the green light signal is the red light alternating current data; and perform comparison based on the at least one component signal of the infrared alternating current signal and the green light signal, and determine that data corresponding to at least one component signal, of the infrared alternating current signal, closest to the green light signal is the infrared alternating current data.

In a possible implementation, the blood oxygen conversion module <NUM> is further configured to: determine pulse blood oxygen based on the red light direct current data, the red light alternating current data, the infrared direct current data, and the infrared alternating current data; and query a pre-configured comparison table based on the pulse blood oxygen, to determine the blood oxygen saturation.

<FIG> is a schematic diagram of another blood oxygen detection apparatus according to an embodiment of this application.

As shown in <FIG>, a blood oxygen detection apparatus is provided. The apparatus includes at least two red light sensors, at least two infrared sensors, a green light sensor, and a processor. The at least two red light sensors are configured to obtain at least two red light signals, the at least two infrared sensors are configured to obtain at least two infrared signals, and the green light sensor is configured to obtain a green light signal. The processor is configured to: determine red light direct current data and a component signal of a red light alternating current signal based on the at least two red light signals; and determine infrared direct current data and a component signal of an infrared alternating current signal based on the at least two infrared signals. The component signal includes an arterial signal. The processor is further configured to: determine red light alternating current data based on the component signal of the red light alternating current signal and the green light signal; and determine infrared alternating current data based on the component signal of the infrared alternating current signal and the green light signal. The processor is further configured to determine blood oxygen saturation based on the red light direct current data, the red light alternating current data, the infrared direct current data, and the infrared alternating current data.

In an example, the processor is further configured to: determine at least two red light direct current signals and at least two red light alternating current signals based on the at least two red light signals; determine the red light direct current data based on the at least two red light direct current signals; determine at least two infrared direct current signals and at least two infrared alternating current signals based on the at least two infrared signals; determine the infrared direct current data based on the at least two infrared direct current signals; determine the component signal of the red light alternating current signal based on the at least two red light alternating current signals; and determine the component signal of the infrared alternating current signal based on the at least two infrared alternating current signals.

In an example, the processor is further configured to: separate at least one component signal of the at least two red light alternating current signals by using an independent component analysis algorithm or a principal component analysis algorithm, to obtain at least one component signal of the red light alternating current signal, where the at least one component signal of the red light alternating current signal includes an arterial signal; and separate at least one component signal of the at least two infrared alternating current signals by using the independent component analysis algorithm or the principal component analysis algorithm, to obtain at least one component signal of the infrared alternating current signal, where the at least one component signal of the infrared alternating current signal includes an arterial signal.

In an example, the processor is further configured to: perform filtering processing on the green light signal; determine the red light alternating current data based on the component signal of the red light alternating current signal and a green light signal obtained after the filtering processing; and determine the infrared alternating current data based on the component signal of the infrared alternating current signal and the green light signal obtained after the filtering processing.

In an example, the processor is further configured to: perform comparison based on the at least one component signal of the red light alternating current signal and the green light signal, and determine that data corresponding to at least one component signal, of a red light alternating current signal, closest to the green light signal is the red light alternating current data; and perform comparison based on the at least one component signal of the infrared alternating current signal and the green light signal, and determine that data corresponding to at least one component signal, of an infrared alternating current signal, closest to the green light signal is the infrared alternating current data.

In an example, the red light direct current data is an average value, a maximum value, a minimum value, or a median of the at least two red light direct current signals. The infrared direct current data is an average value, a maximum value, a minimum value, or a median of the at least two infrared direct current signals.

In an example, the processor is further configured to: determine pulse blood oxygen based on the red light direct current data, the red light alternating current data, the infrared direct current data, and the infrared alternating current data; and query a pre-configured comparison table based on the pulse blood oxygen, to determine the blood oxygen saturation.

In an example, the apparatus is a wearable intelligent device, and includes a watchband and an intelligent wearable device body. At least one red light sensor and at least one infrared sensor are disposed on the watchband. At least one red light sensor, at least one infrared sensor, and a processor are disposed on the intelligent wearable device body. A green light sensor is disposed on the watchband or the intelligent wearable device body.

In an example, at least two detection points are disposed on the blood oxygen detection apparatus. A red light sensor and an infrared sensor are disposed at each detection point. Arteries at a wrist are mostly distributed in a deep part of a human body, while veins are distributed near a surface of skin. A signal measured on the back of the wrist contains more venous compositions. On both sides of the wrist, arteries near ulna styloid process and radial styloid process are slightly near the skin, and data from these two positions contains less venous compositions. As shown in <FIG>, the blood oxygen detection apparatus may be in a form of a smart watch, and two detection points <NUM>/<NUM> and <NUM>/<NUM> may be disposed on the smart watch. The detection points <NUM>/<NUM> may be disposed on a back of a watch face of the smart watch. When the smart watch is worn, the detection point <NUM>/<NUM> is disposed on a back of a wrist of a user. The detection point <NUM>/<NUM> may be located within a <NUM> range of the ulna styloid process or radial styloid process. In other words, the detection point <NUM>/<NUM> may be disposed on the watchband. <NUM> and <NUM> are red light sensors, and <NUM> and <NUM> are infrared sensors. In addition, the apparatus is further provided with a photoplethysmography (photo plethysmo graphy, PPG) sensor, namely, the foregoing green light sensor, which is marked as <NUM> in <FIG>.

A person skilled in the art should note that a location of the detection point may be any location on the device. <FIG> is merely an optional implementation, and any equivalent replacement falls within the protection scope of this application. A specific location of the detection point is not limited herein. A person skilled in the art should further note that the red light sensor and the infrared sensor at the detection point may be separated, or may be integrated together. A person skilled in the art should further note that a location of the PPG sensor used to detect green light may also be any location on the device. <FIG> is merely an optional implementation, and any equivalent replacement falls within the protection scope of this application. A specific location of the PPG sensor is not limited herein.

In this application, more information is collected by using the plurality of measurement points, then a plurality of component signals are separated from collected alternating current information by using the independent component analysis algorithm or the principal component analysis algorithm, and denoising is performed by using the green light signal, so that interference caused by venous blood flows, capillaries, and the like can be eliminated, a disadvantage of a low signal-to-noise ratio can be made up and accuracy of a blood oxygen measurement on the wrist is increased.

An ordinary person in the art may be further aware that, in combination with the examples described in the embodiments disclosed in this specification, units and algorithm steps may be implemented by electronic hardware, computer software, or a combination thereof. To clearly describe the interchangeability between the hardware and the software, the foregoing has generally described compositions and steps of each example according to functions.

Claim 1:
A blood oxygen detection method performed by a wearable intelligent device that comprises: a watchband; an intelligent wearable device body; at least one red light sensor (<NUM>) and at least one infrared sensor (<NUM>) disposed on the watchband; at least one red light sensor (<NUM>), at least one infrared sensor (<NUM>), and a processor disposed on the intelligent wearable device body; and a green light sensor (<NUM>) disposed on the watchband or the intelligent wearable device body, wherein the method comprises:
obtaining (S201) at least two red light signals from the red light sensors (<NUM>, <NUM>), at least two infrared signals from the infrared sensors (<NUM>, <NUM>), and a green light signal from the green light sensor (<NUM>);
determining (S202) red light direct current data and a component signal of a red light alternating current signal based on the at least two red light signals; and determining infrared direct current data and a component signal of an infrared alternating current signal based on the at least two infrared signals, wherein the component signal comprises an arterial signal;
determining (S203) red light alternating current data based on the component signal of the red light alternating current signal and the green light signal; and determining infrared alternating current data based on the component signal of the infrared alternating current signal and the green light signal; and
determining (S204) blood oxygen saturation based on the red light direct current data, the red light alternating current data, the infrared direct current data, and the infrared alternating current data.