CN105997104B - It is a kind of based on multi fiber beam in body noninvasive physiological parameter acquisition method and device in real time - Google Patents

Abstract

The present invention provides an in-vivo real-time non-invasive physiological parameter acquisition method and device based on multi-fiber bundles, including an optical module and an electrical module. Mechanical structure composition. Fiber optic bundles capture reflected and transmitted light intensity for physiological parameters. The electrical module includes a dual-channel preamplifier unit, a dual-channel filter unit, a dual-channel numerical control amplifying unit, a processor unit, a display and input unit, a voltage follower unit, an analog selection unit, and a voltage-current conversion unit. The processor unit calculates the number of physiological parameter measurement wavelengths and the change of the ratio of transmitted and reflected light intensity over time to extract characteristic parameter values from the signal, and determines the total number of acquired characteristic parameter values. According to the partial least squares method and the high-precision reference voltage The unit calculates the expression of the physiological parameter, the present invention can effectively improve the measurement accuracy of the physiological parameter of the human body, and is non-invasive to the human body, with high measurement accuracy and convenient use.

Description

A method and device for in vivo real-time non-invasive physiological parameter acquisition based on multi-fiber bundles

technical field

The patent of the present invention relates to the field of biomedical signal processing, in particular to a method and device for in-vivo real-time non-invasive physiological parameter acquisition based on multi-fiber bundles.

Background technique

At present, there have been many instruments or devices that use optical methods to achieve non-invasive acquisition of physiological parameters. For example, the blood oxygen saturation meter uses two single-wavelength lights with wavelengths of 940nm and 660nm to irradiate the fingertips in turn, and calculates the corresponding blood oxygen saturation value by detecting the change of light intensity after transmission, but the two The light path of the irradiation wavelength through the finger is different, so the measurement accuracy will be affected; in addition, this method cannot measure the reflected light intensity. If the reflected light intensity can be measured, the measurement accuracy will be increased. There is also the measurement of photoelectric volume wave, which is generally irradiated by infrared light to ensure that the light intensity of the irradiation light is basically unchanged, and the light intensity after passing through the finger or earlobe is measured. Similarly, if the reflected light can be measured, a part of the incident light can be eliminated by means of the reflected light. The effect of optical instability on volumetric waves. Therefore, the present invention proposes an in-vivo real-time non-invasive physiological parameter acquisition method and device based on a multi-fiber bundle, which can well overcome the above shortcomings.

SUMMARY OF THE INVENTION

The present invention proposes an in-vivo real-time non-invasive physiological parameter acquisition method based on multi-fiber bundles, comprising the following steps:

The first step: determine the wavelength and number of detection waves of various physiological parameters;

Step 2: Measure a certain part of the human body for many times, measure the body temperature of the measured person through the temperature sensor, and measure the value of the corresponding physiological parameter through other equipment. According to the wavelength and number of detection waves determined in the first step, for the same parameter , in the case of different wavelengths, obtain the ratio of transmitted light intensity to reflected light intensity and the change of time, and record the total number N of wavelengths used in the actual measurement;

The third step: using the above ratio of transmitted light intensity to reflected light intensity and the change with time, calculate the average value of the maximum value and the average value of the minimum value of the ratio of the transmitted and reflected light intensity within the set pulsation period, And extract the characteristic parameter value from the change signal of the ratio of transmitted and reflected light intensity with time, and determine the total number M of characteristic parameter values obtained;

Step 4: Use personalized fitting for each measured physiological parameter, and set a certain physiological parameter to be measured as y*, then its expression is expressed as:

In formula (1), M is the total number of acquired characteristic parameter values, N is the total number of wavelengths used in actual measurement, c ₀ represents the fitting calculation coefficient, and c _2i-1 represents the calculation coefficient of the i-th characteristic parameter , R _i represents the value of the ith characteristic parameter, R _maxi and R _mini represent the average value of the maximum value and the average value of the minimum value of the ratio of transmitted light and reflected light at the ith wavelength in the pulsation period, respectively, k _{2i -1} , k _2i , l _2i-1 , and l _2i represent the calculation coefficients of the first power and the second power of R _maxi and R _mini respectively, T _b indicates the body temperature during measurement, c _Tb indicates the first power of the above body temperature T _b The calculation coefficient of , c _Tb ′ represents the calculation coefficient of the quadratic power of the above-mentioned body temperature T _b , and each of the above-mentioned coefficients is obtained by the partial least squares method.

Further, the first step of the step also includes: using an ultraviolet-visible-near-infrared spectrophotometer to scan human whole blood, and according to the absorption peaks of each group, functional group or molecule in the chemistry, it can be determined that the physiological needs to be measured are determined. Parameter-related and irrelevant wavelengths or wavelength ranges; for the above wavelengths or wavelength ranges, select 1 to 4, respectively, to determine the number of detection wavelengths.

Further, in the fourth step of the step, the partial least squares method is used to obtain the coefficients of the y* expression of the physiological parameter value to be measured, and the specific method is as follows: let x ₀ =1, x _2i-1 =R _i , x _2i =(R _i ) ² , x _2i-1+2M =R _maxi , x _2i+2M =R _maxi ² , x _2i-1+2(M+N) =R _mini , x _{2i+2(M+ N)} =R _mini ² , x _2(M+2N)+1 =T _b , x _2(M+2N)+2 =T _b ² , the former corresponding coefficients are represented by a _i in turn, then formula (1) can be replaced with:

Let _L=2(M+2N) , then formula (2) can be further abbreviated as: The corresponding physiological parameter value measured by equipment or method is represented by y, and the same person has been measured K times, and K>L, and y _m is used to represent the mth value of the corresponding parameter measured by other equipment or method, y _m * represents The fitted value of the mth data, then its difference δ _m = |y _m -y _m *|, according to formula (3), y _m * can be expressed as:

According to the principle of partial least squares, to make minimum, i.e. minimum. Then there are:

Arranging formula (5), we get: According to formula (6), the coefficients a _i in formula (2) can be solved, and a _i is brought into formula (1) to obtain a complete expression of the physiological parameter value to be measured as y*.

An in-vivo real-time non-invasive physiological parameter acquisition device based on multi-fiber bundles, comprising an optical module and an electrical module, the optical module comprising an optical fiber bundle group, a monochromatic light source group that provides corresponding light wavelengths and required illumination light intensity for measurement, A photoelectric sensor that converts the changing optical signal into an electrical signal, the optical fiber bundle group gathers various monochromatic light in a small area, acquires reflected and transmitted light from a small area, and transmits the light through the photoelectric sensor. Converted into electrical signals and sent to the electrical module for processing; the electrical module includes a dual-channel preamplifier unit that converts the changes in the transmitted light intensity and reflected light intensity acquired by the photoelectric sensor into voltages proportional to the respective light intensities , converts the voltage converted from the change of transmitted light intensity and reflected light intensity into corresponding digital values, provides a high-precision reference voltage to the outside, and a processor unit that controls other units of the device, and converts the high-precision voltage into current. input to the voltage-current conversion unit of the monochromatic light source group.

Further, the optical module further includes a mechanical structure for fixing the above-mentioned optical fiber bundle group, monochromatic light source group, and photoelectric sensor into one body.

Further, the monochromatic light source group is composed of LEDs with various monochromatic wavelengths.

Further, the electrical unit also includes a dual-channel filtering unit located between the dual-channel preamplifier unit and the processor unit, and is provided with a dual-channel filtering unit that filters the voltage signal converted from the transmitted light intensity and the reflected light intensity change, and selects an appropriate multiple to perform the filtering. Amplified dual-channel digitally controlled amplifying unit; located between the voltage-current conversion unit and the processor unit, an analog selection unit controlled by the processor unit and capable of selecting the output of the corresponding channel, the analog selection unit and the processor A voltage follower unit is arranged between the units; the electrical unit further includes a display and input unit.

Further, the dual-channel preamplifier unit, dual-channel filter unit, dual-channel digitally controlled amplification unit, processor unit, display and input unit, voltage follower unit, analog selection unit, and voltage-current conversion unit are converted by DC-DC voltage. Unit is powered.

Further, the processor unit includes D/A conversion and A/D conversion; the processor unit is set with reference values and linear correction values under different magnifications.

Effective gain: The present invention proposes a new optical path structure that can simultaneously detect the reflected light intensity and the transmitted light intensity, which can effectively improve the measurement accuracy of human physiological parameters, and is non-invasive to the human body, with high measurement accuracy and convenient use. The optical module of the invention is designed with an optical fiber bundle group, which can effectively reduce the influence of stray light and is easy to assemble.

Description of drawings:

Fig. 1 is the hardware principle block diagram of the present invention;

FIG. 2 is a schematic diagram of real-time data acquisition of an optical module.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

The present invention proposes an in-vivo real-time non-invasive physiological parameter acquisition method based on multi-fiber bundles, comprising the following steps:

Step 1: Determine the wavelength and number of detection waves for each physiological parameter

Use UV-Vis-NIR spectrophotometer to scan human whole blood in the range of 185nm-3300nm, and analyze the absorption peaks and relatively flat wavelengths of the whole blood, and compare the various groups, functional groups or Analyze the absorption peaks of molecules, etc., analyze the reasons for the appearance of each absorption peak, determine the wavelength or wavelength range that is closely related to the physiological parameters to be measured, and determine the wavelength or wavelength that does not change much or does not change with the physiological parameters to be measured. scope. In this embodiment, if the correlation with the wavelength or wavelength range to be measured is less than 5%, it is regarded as a wavelength or wavelength range that does not change much from the physiological parameter to be measured.

Determine the number of measurement wavelengths according to the acquired data and the number of physiological parameters to be measured. The specific principle is: ensure that 1 to 4 wavelengths are selected from each wavelength or wavelength range that is closely related to each physiological parameter to be measured, and 1 to 4 are selected from the wavelength or wavelength range that has little or no change with each physiological parameter to be measured. The same wavelength can be selected as far as possible for different physiological parameters, so as to reduce the total number of selected wavelengths.

The second step is to measure a certain part of the human body multiple times, measure the body temperature of the measured person through the temperature sensor, and measure the value of the corresponding physiological parameter through other equipment. According to the wavelength and number of detection waves determined in the first step, for the same parameter , in the case of different wavelengths, obtain the ratio of transmitted light intensity to reflected light intensity and the change of time, and determine the total number N of wavelengths used for actual measurement. The principle of determination is to ensure the measurement accuracy of each physiological parameter to be measured. On the premise, use as few wavelengths as possible.

The third step: using the above ratio of transmitted light intensity to reflected light intensity and the change with time, calculate the average value of the maximum value and the average value of the minimum value of the ratio of the transmitted and reflected light intensity within the set pulsation period, The characteristic parameter values are extracted from the time-varying signal of the ratio of transmitted and reflected light intensity to determine the total number M of characteristic parameter values obtained. In this embodiment, 2 to 100 pulse periods can be selected.

Step 4: Use personalized fitting for each measured physiological parameter, and perform data fitting using the data obtained above and the partial least squares method. The specific method is:

Assuming that a certain physiological parameter value to be measured is y*, its expression is expressed as:

In formula (1), M is the total number of acquired characteristic parameter values, N is the total number of wavelengths used in actual measurement, c ₀ represents the fitting calculation coefficient, and c _2i-1 represents the calculation coefficient of the i-th characteristic parameter , R _i represents the value of the ith characteristic parameter, R _maxi and R _mini represent the average value of the maximum value and the average value of the minimum value of the ratio of transmitted light and reflected light at the ith wavelength in the pulsation period, respectively, k _{2i -1} , k _2i , l _2i-1 , and l _2i represent the calculation coefficients of the first power and the second power of R _maxi and R _mini respectively, T _b indicates the body temperature during measurement, c _Tb indicates the first power of the above body temperature T _b The calculation coefficient of , c _Tb ' represents the calculation coefficient of the quadratic power of the above-mentioned body temperature T _b .

The partial least squares method is used to obtain the coefficients of the expression of the physiological parameter value y* to be measured. The specific method is: let x ₀ =1, x _2i-1 =R _i , x _2i =(R _i ) ² , x _2i-1+2M =R _maxi , x _2i+2M =R _maxi ² , x _2i-1+2(M+N) =R _mini , x _2i+2(M+N) =R _mini ² , x _{2( M+2N)+1} =T _b , x _2(M+2N)+2 =T _b ² , the former corresponding coefficients are represented by a _i in turn, then formula (1) can be replaced by:

Let L=2(M+2N), then formula (2) can be further abbreviated as:

Assume that the corresponding physiological parameter values measured by other equipment or methods are represented by y, and the same person has been measured K times, and K>L, and y _m is used to represent the mth value of the corresponding parameter measured by other equipment or methods, y _m * represents the fitted value of the mth data, then its difference δ _m = |y _m -y _m *|, according to formula (3), y _m * can be expressed as:

According to the principle of partial least squares, to make minimum, i.e. minimum. Then there are:

Arranging formula (5), we can get:

After arranging formula (6), we have:

where (k=0,...,L) (7)

because So formula (7) can be organized as:

where (k=0,...,L) formula (8) can also be written as:

The same physiological parameter data measured by N other devices, and the data of the expression y* measured in the method of the present invention, are brought into the L+1 equations in the formula (9) to solve _{a 0 , a 1 , . _} ² , x _2i-1+2M =R _maxi , x _2i+2M =R _maxi ² , x _2i-1+2(M+N) =R _mini , x _2i+2(M+N) =R _mini ² , x _2(M+2N)+1 =T _b , x _2(M+2N)+2 =T _b ² , and entering formula (1), a complete y* expression can be obtained.

An in vivo real-time non-invasive physiological parameter acquisition device based on multi-fiber bundles, as shown in Figure 1, includes an optical module and an electrical module. The core part of the electrical module is a processor unit, and in this embodiment, the processor unit is 32 bits. On the one hand, the electrical module provides a high-precision reference voltage through the D/A conversion in the 32-bit processor unit, and after the voltage follower unit, under the control of the 32-bit processor unit, select the corresponding voltage through the analog selection unit. The output of the channel is converted into a high-precision current by the subsequent voltage-current conversion unit and input to the monochromatic light source group in the optical module, so that the electrical module can realize the high-precision control of the LED brightness that constitutes the monochromatic light source group; another On the one hand, the double-channel pre-amplifier unit is used to convert the changes of the transmitted light intensity and reflected light intensity acquired by the photoelectric sensor in the optical module into a voltage proportional to the respective light intensities, and the double-channel filter unit filters out various interference signals. Then, under the control of the 32-bit microprocessor unit, select the appropriate magnification through the dual-channel numerical control amplifying unit and then send it to the 12-bit A/D conversion in the 32-bit microprocessor unit to realize the voltage conversion. It is the corresponding digital value, and at the same time, the A/D-converted value of the voltage provided by the external high-precision reference voltage unit is used, and 32 is the reference value and linear correction value under different magnifications set by the microprocessor unit to further improve the voltage. The measurement accuracy is to improve the accuracy of the transmitted light intensity and the reflected light intensity, and at the same time, the corresponding values of the physiological parameters to be measured are obtained through corresponding calculations, and displayed through the display and input unit. The DC-DC voltage conversion unit mainly provides the learned power for each unit of the device.

The optical module is mainly composed of a fiber bundle group, a monochromatic light source group, a photoelectric sensor and a mechanical structure. When the optical module collects real-time data, as shown in Figure 2, place a finger or earlobe on the optical module. The optical fiber bundle group gathers various monochromatic lights in a small area, and obtains reflected and transmitted light from a small area, and converts the light into electrical signals through the photoelectric sensor and sends it to the electrical module for processing. It can evenly illuminate the corresponding parts of the measurement to improve the overall measurement accuracy. The practical fiber bundle group can also effectively reduce the influence of stray light, and the assembly is convenient. The monochromatic light source group is mainly composed of LEDs with various monochromatic wavelengths, which provide corresponding light wavelengths and required illumination light intensity for measurement. The photoelectric sensor mainly converts the changing optical signal into an electrical signal and transmits it to the electrical module. The mechanical structure mainly fixes the above-mentioned optical fiber bundle group, monochromatic light source group, and photoelectric sensor in one, so as to facilitate the measurement of human physiological parameters.

The technical solutions provided by the embodiments of the present invention are described in detail above, and the principles and implementations of the embodiments of the present invention are described in this paper by using specific examples. At the same time, for those of ordinary skill in the art, according to the embodiments of the present invention, there will be changes in the specific implementation and application scope. To sum up, the content of this specification should not be construed as a limitation of the present invention.

Claims (7)

1. an in vivo real-time non-invasive physiological parameter acquisition method based on a multi-fiber bundle, is characterized in that, comprises the following steps: The first step: determine the wavelength and number of detection waves of various physiological parameters; Step 2: Measure a certain part of the human body for many times, measure the body temperature of the measured person through the temperature sensor, and measure the value of the corresponding physiological parameter through other equipment. According to the wavelength and number of detection waves determined in the first step, for the same parameter , in the case of different wavelengths, obtain the ratio of transmitted light intensity to reflected light intensity and the change of time, and record the total number N of wavelengths used in the actual measurement; The third step: using the above ratio of transmitted light intensity to reflected light intensity and the change with time, calculate the average value of the maximum value and the average value of the minimum value of the ratio of the transmitted and reflected light intensity within the set pulsation period, And extract the characteristic parameter value from the change signal of the ratio of transmitted and reflected light intensity with time, and determine the total number M of characteristic parameter values obtained; Step 4: Use personalized fitting for each measured physiological parameter, and set a certain physiological parameter to be measured as y*, then its expression is expressed as: In formula (1), M is the total number of acquired characteristic parameter values, N is the total number of wavelengths used in actual measurement, c ₀ represents the fitting calculation coefficient, and c _2i-1 represents the calculation coefficient of the i-th characteristic parameter , R _i represents the value of the ith characteristic parameter, R _maxi and R _mini represent the average value of the maximum value and the average value of the minimum value of the ratio of transmitted light and reflected light at the ith wavelength in the pulsation period, respectively, k _{2i -1} , k _2i , l _2i-1 , and l _2i represent the calculation coefficients of the first power and the second power of R _maxi and R _mini respectively, T _b indicates the body temperature during measurement, c _Tb indicates the first power of the above body temperature T _b The calculation coefficient of , c _Tb ' represents the calculation coefficient of the quadratic power to the above-mentioned body temperature T _b , and the above-mentioned coefficients are obtained by the partial least squares method; The partial least squares method is used to obtain the coefficients of the y* expression of the physiological parameter to be measured. The specific method is as follows: let x ₀ =1, x _2i-1 =R _i , x _2i =(R _i ) ² , x _2i-1+2M =R _maxi , x _2i+2M =R _maxi ² , x _2i-1+2(M+N) =R _mini , x _2i+2(M+N) =R _mini ² , x _{2( M+2N)+1} =T _b , x _2(M+2N)+2 =T _b ² , and the corresponding coefficients are represented by a _i in turn, then formula (1) can be replaced by: Let L=2(M+2N), then formula (2) can be further abbreviated as: The corresponding physiological parameter value measured by equipment or method is represented by y, and the same person has been measured K times, and K>L, and y _m is used to represent the mth value of the corresponding parameter measured by other equipment or method, y _m * represents The fitted value of the mth data, then its difference δ _m = |y _m -y _m *|, according to formula (3), y _m * can be expressed as: According to the principle of partial least squares, to make minimum, i.e. Minimum, then there are: Arranging formula (5), we get: According to formula (6), the coefficients a _i in formula (2) can be solved, and a _i is brought into formula (1) to obtain a complete expression of the physiological parameter value to be measured as y*. 2 . The method for collecting real-time non-invasive physiological parameters in vivo based on a multi-fiber bundle according to claim 1 , wherein the first step of the step further comprises: using an ultraviolet-visible-near infrared spectrophotometer to detect the Whole blood is scanned, and according to the absorption peaks of each group, functional group or molecule in the chemistry, the relevant and irrelevant wavelengths or wavelength ranges to be measured physiological parameters are determined; The number of detection wavelengths. 3. A device utilizing the multi-fiber bundle-based in-vivo real-time non-invasive physiological parameter acquisition method according to claim 1, characterized in that it comprises an optical module and an electrical module, and the optical module comprises a A monochromatic light source group corresponding to the light wavelength and the required illumination intensity, a photoelectric sensor that converts the changing light signal into an electrical signal, the fiber bundle group gathers various monochromatic light in a small range, and from a small The reflected and transmitted light are acquired within the range, and the light is converted into an electrical signal by the photoelectric sensor and sent to the electrical module for processing; the electrical module includes converting the transmitted light intensity and reflected light intensity acquired by the photoelectric sensor into A dual-channel preamplifier unit with a voltage proportional to the respective light intensity, converts the voltage converted from the change of the transmitted light intensity and the reflected light intensity into a corresponding digital value, provides a high-precision reference voltage to the outside, and controls other units of the device an active processor unit, which converts the high-precision voltage into a current and inputs it to the voltage-current conversion unit of the monochromatic light source group; The electrical unit also includes a dual-channel filter unit located between the dual-channel preamplifier unit and the processor unit, which is provided with a dual-channel filter unit for filtering the voltage signal converted from the transmitted light intensity and the reflected light intensity change, and a dual-channel filter unit that selects an appropriate multiple for amplification. A channel digitally controlled amplifying unit; located between the voltage-current conversion unit and the processor unit, an analog selection unit controlled by the processor unit that can select the output of the corresponding channel, and is set between the analog selection unit and the processor unit There is a voltage follower unit; the electrical unit also includes a display and input unit. 4 . The multi-fiber bundle-based in-vivo real-time non-invasive physiological parameter acquisition device according to claim 3 , wherein the optical module further comprises fixing the above-mentioned optical fiber bundle group, monochromatic light source group, and photoelectric sensor. 5 . integrated mechanical structure. 5 . The multi-fiber bundle-based real-time non-invasive physiological parameter acquisition device in vivo according to claim 3 , wherein the monochromatic light source group is composed of LEDs with various monochromatic wavelengths. 6 . 6 . The in-vivo real-time non-invasive physiological parameter acquisition device based on a multi-fiber bundle according to claim 3 , wherein the dual-channel preamplifier unit, the dual-channel filter unit, the dual-channel numerical control amplifying unit, the processing The controller unit, the display and input unit, the voltage follower unit, the analog selection unit, and the voltage-current conversion unit are powered by the DC-DC voltage conversion unit. 7 . The multi-fiber bundle-based in vivo real-time non-invasive physiological parameter acquisition device according to claim 3 , wherein the processor unit includes D/A conversion and A/D conversion; the processor The unit is set with reference values and linear correction values under different magnifications.