CN108742644B

CN108742644B - Fetal blood oxygen saturation signal processing method, light receiving device and detection device

Info

Publication number: CN108742644B
Application number: CN201810169917.2A
Authority: CN
Inventors: 黄汶; 王义向
Original assignee: Beijing Weitexing Technology Co ltd
Current assignee: Beijing Weitexing Technology Co ltd
Priority date: 2018-02-28
Filing date: 2018-02-28
Publication date: 2021-02-19
Anticipated expiration: 2038-02-28
Also published as: CN108742644A

Abstract

The invention provides a method for processing a fetal blood oxygen saturation detection signal without wound outside the abdomen, which synthesizes a plurality of received optical signals related to the fetal blood oxygen saturation into an optical signal sum and comprises the following steps: respectively carrying out correlation analysis on a plurality of received optical signals related to the fetal blood oxygen saturation and a fetal heart rate signal to obtain correlation coefficients of the optical signals; and B: obtaining a weighting coefficient corresponding to each optical signal based on the correlation coefficient; and C: superposing the plurality of optical signals according to respective weighting coefficients to obtain an optical signal sum related to the fetal blood oxygen saturation so as to improve the intensity of the received optical signals related to the fetal blood oxygen saturation, remove noise signal interference and improve the signal-to-noise ratio; the invention also provides a light receiving device and an extraabdominal noninvasive fetal blood oxygen saturation detection device which adopt the signal processing method.

Description

Fetal blood oxygen saturation signal processing method, light receiving device and detection device

Technical Field

The invention relates to the technical field of oxyhemoglobin saturation detection in medical equipment, in particular to an extraabdominal noninvasive fetal oxyhemoglobin saturation signal processing method, an optical receiving device and an extraabdominal noninvasive fetal oxyhemoglobin saturation detection device.

Background

Late pregnancy, as well as the temporary and productive phase, can be a dangerous time period for the pregnant woman and the fetus. If the umbilical cord of the fetus becomes twisted in an unfavorable position, the placenta separates prematurely, or some diseases of the pregnant woman and fetus may result in insufficient oxygen in the blood of the fetus, which may lead to brain damage or death of the fetus. Pulse oximetry (SaO) for clinical medicine₂) This physiological parameter is used to indirectly monitor the oxygen content of the human body, including the blood of the fetus.

Currently, fetal heart rate and heart sound monitors are widely used for monitoring the physiological status of a fetus. Since the oxygen supply of the fetus is not obtained by the respiration of the fetus but is transferred from the placenta by the mother, the blood oxygen saturation of the fetus can more accurately reflect the oxygen concentration in the blood, and thus is a physiological index which more directly reflects the life state of the fetus. Detecting SaO of a fetus₂Has the clinical significance of directly reflecting the oxygenation condition of the fetus, so as to determine the life state of the fetus in the mother body and reduce the death rate of the perinatalDisability rate in newborn infants. In 2000, an instrument for measuring the blood oxygen saturation degree of a fetus is produced by American companies, and medical staff needs to put the instrument into the uterus of a pregnant woman and directly take blood from the surface of the fetus to obtain the blood oxygen saturation degree index of the fetus. The methods and the instruments are not suitable for detecting the blood oxygen saturation of the fetus continuously for a long time, and are not suitable for perinatal monitoring of the fetus. Because there is no instrument or equipment for detecting the blood oxygen saturation of the fetus in an effective non-invasive manner, medical staff often only can rely on a fetal heart rate monitoring instrument. The fetal heart monitoring widely used at present can sensitively detect the asphyxia of the fetus, but has low specificity and cannot reflect the precursor of the asphyxia in advance. Because the specificity of fetal heart monitoring is low, doctors lack sufficient knowledge of the whole state of the fetus, such as whether to carry out caesarean section or not, when to start the caesarean section, and urgent medical decisions must be made without sufficient knowledge, so that on one hand, the doctors can make wrong diagnoses and delay the time for taking necessary measures; on the other hand, doctors are often too cautious, resulting in an increase of many unnecessary caesarean section surgical interventions, not only increasing the surgical risk and the complications of childbirth of pregnant women, but also the associated unnecessarily high medical costs and increasing the economic burden on society and families.

The inventor of the present invention provides a detection system and a method for monitoring the fetal pulse blood oxygen saturation in a non-invasive way in Chinese patent ZL201310182965.2 (fetal blood oxygen saturation detection system and method), firstly adopts a fetal pulse blood oxygen saturation photoelectric sensor placed outside a pregnant woman body, does not need any operation deep into the abdomen of the pregnant woman in the detection process, does not need to apply the photoelectric sensor to a specific part of the fetus, thereby really realizing the non-invasive fetal blood oxygen saturation detection outside the abdomen, and can simultaneously provide two important fetal physiological parameters of the heart rate of the fetus and the fetal blood oxygen saturation to medical care personnel, and the detection system and the detection method have very high practical significance to the fetus, the pregnant woman and the society. The present invention is a new invention further developed in the process of implementing specific products according to the above patent development. The applicant has found that the position of the fetus in the mother's uterus is a result ofThe fetal position (fetal position) has great uncertainty, the fetal positions of different pregnant women are different, the fetal positions of the same pregnant woman in different gestational stages are greatly changed, the postures of the fetus in the uterus can be changed at any time, and the blood oxygen saturation levels of different parts of the fetus are different, so when the fetus SaO of the Chinese patent ZL201310182965.2 is adopted₂When the photoelectric sensor of the detection system is applied to a specific part outside the abdomen of the pregnant woman, the photoelectric sensor senses the SaO of the fetus₂There is a large uncertainty in the relevant photoelectric signal, which directly affects the specificity of the detection result, i.e. when the detection result shows positive (blood oxygen saturation is low), the actual Sa02 of the fetus is normal. As a result of this situation, unnecessary human and even surgical interventions may be involved, which may lead to increased medical costs and risks, as well as increased mother-to-baby pain. Therefore, the non-invasive fetal blood oxygen saturation detection outside the abdomen is realized by solving the problem that the uncertainty of fetal position affects the detection result, and the other problem is the light attenuation problem, the light signal received by the light receiver needs to be the light with a specific wavelength which is irradiated from the outside of the abdomen of the pregnant woman to the fetus in the abdominal cavity of the pregnant woman and then returned from the fetus to the outside of the abdomen of the pregnant woman through the abdominal cavity of the pregnant woman, the light needs to pass through a long optical path from emitting to receiving, and the light attenuation is in direct proportion to the square of the optical path. In addition, the optical signal related to the blood oxygen saturation level of the fetus received by the optical receiver is extremely weak light after complex processes such as absorption, reflection, scattering and the like of tissues of the fetus and tissues of a pregnant woman (such as skin, fat, uterus, amniotic fluid and the like), and the weak degree is enough to threaten the success of detection and the practicability of non-invasive fetus blood oxygen saturation level detection outside the abdomen. Therefore, the noninvasive blood oxygen saturation detection device for abdominal and external infants has to solve the problems of signal intensity related to fetal blood flow received by the light receiving device and signal interference, improve the signal intensity, remove noise interference and improve the signal-to-noise ratio. Therefore, to develop a successful noninvasive oximetry device for abdominal and external infants, the two problems must be solved at the same time, and therefore, the problem that the light-emitting and light-receiving devices receive the signal intensity related to the blood flow of the fetus becomes the key to solve the two problems.

The applicant also found in the research that the abdominal and external noninvasive blood oxygen saturation monitoring system must have enough light to irradiate the abdomen of the pregnant woman to ensure that the light receiver receives effective light signals related to the fetus, however, if the light emitting power of the light source is increased, the light emitting area is small based on the currently used light emitting elements (such as LED and laser), and the light emitting elements are usually tightly attached to the skin of the pregnant woman, so that the skin of the pregnant woman feels uncomfortable or can be burnt during use. According to the International Commission on non-Ionizing Radiation Protection (ICNIRP) 2000 published document, it is known that the light power of several milliwatts for LED light waves with the wavelength ranging from 400nm to 1400nm lasts for 100 seconds, which can cause skin burns. Therefore, it is also necessary to eliminate the risk of damage caused by the locally burnt optical radiation to improve the practicability and comfort of the detection device.

Disclosure of Invention

The invention aims to provide an extraabdominal noninvasive fetal blood oxygen saturation signal processing method for improving the intensity of a received optical signal related to fetal blood oxygen saturation, removing noise signal interference and having high signal-to-noise ratio, an optical receiving device adopting the extraabdominal noninvasive fetal blood oxygen saturation signal processing method and an extraabdominal noninvasive fetal blood oxygen saturation detection device.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for processing a signal for detecting the blood oxygen saturation of a fetus without wound outside the abdomen synthesizes a plurality of received optical signals related to the blood oxygen saturation of the fetus into an optical signal sum, and comprises the following steps:

step A: respectively carrying out correlation analysis on a plurality of received optical signals related to the fetal blood oxygen saturation and a fetal heart rate signal to obtain correlation coefficients of the optical signals;

and B: obtaining a weighting coefficient corresponding to each optical signal based on the correlation coefficient;

and C: and superposing the plurality of optical signals according to the respective weighting coefficients to obtain the optical signal sum related to the blood oxygen saturation of the fetus.

Further, step B includes: if the correlation coefficient of the optical signal is lower than a preset correlation threshold value, the weighting coefficient is 0; and if the correlation coefficient is higher than a preset correlation threshold value, obtaining a weighting coefficient according to the correlation coefficient, and superposing the plurality of optical signals according to the respective weighting coefficients to obtain an optical signal sum.

Further, step a comprises: and carrying out correlation analysis on each received optical signal related to the fetal blood oxygen saturation and the received fetal heart rate signal in a time domain to obtain a correlation coefficient of each optical signal.

Further, step a comprises: and converting each received optical signal related to the fetal blood oxygen saturation from a time domain to a frequency domain to obtain an optical signal spectrum, converting the received fetal heart rate signal from the time domain to the frequency domain to obtain a fetal frequency domain optical power spectrum, and performing correlation analysis on the optical signal spectrum in the frequency domain and the fetal frequency domain optical power spectrum to obtain a correlation coefficient of each optical signal.

Further, step a further comprises: and filtering out signal spectrum power except the fetal spectrum power from the optical signal spectrum to obtain a filtered optical signal spectrum, and restoring the filtered optical signal spectrum from a frequency domain to a time domain to obtain a filtered optical signal serving as a weighted and superposed optical signal.

Further, the method also comprises the step D: and analyzing and calculating the sum of the optical signals related to the blood oxygen saturation of the fetus and the acquired pregnant woman heart rate, and/or pregnant woman optical signals, and/or fetus heart rate signals to obtain the blood oxygen saturation of the fetus.

The invention also provides an optical receiving device for the extraabdominal noninvasive fetal blood oxygen saturation detection device, which comprises a plurality of optical receivers 204 and a signal primary processor 250 connected with the plurality of optical receivers 204, wherein the signal primary processor 250 comprises an interface for receiving a fetal heart rate signal, and the primary processor 250 synthesizes a plurality of received optical signals related to fetal blood oxygen saturation into an optical signal sum through the extraabdominal noninvasive fetal blood oxygen saturation detection signal processing method.

Further, the signal primary processor 250 includes a plurality of signal analyzers 252 and an adding selector 254 connected to the plurality of signal analyzers 252, the plurality of signal analyzers 252 analyze the correlation coefficients of the optical signals related to the fetal blood oxygen saturation and the fetal heart rate signal collected by the plurality of optical receivers 204, respectively, and the adding selector 254 weights and adds the plurality of paths of digital signals according to the analysis result of the signal analyzers 252 to synthesize an optical signal sum 256.

Further, the signal analyzer 252 is a time domain signal analyzer or a frequency domain signal analyzer.

Further, the adding selector 254 is a linear adder, and the linear adder linearly adds the multiple digital signals processed by the signal analyzer 252 to form a combined optical signal sum 256; alternatively, the addition selector 254 is an optical signal selector, and the optical signal selector selects one path from the multiple paths of digital signals processed by the signal analyzer 252 as the optical signal sum 256, or selects multiple paths of digital signals from the multiple paths of digital signals and superimposes the multiple paths of digital signals to form the optical signal sum 256.

Further, the signal primary processor 250 is a single chip microcomputer.

The invention also provides an extraabdominal noninvasive fetal blood oxygen saturation detection device, which comprises an extraabdominal fetal oximeter with a signal processing controller 11, a luminous light source device 92, a light receiving device 91 used for collecting optical signals related to fetal blood oxygen saturation from the extraabdominal of a pregnant woman, and a fetal heart collecting device used for collecting fetal heart rate signals, wherein the luminous light source device 92, the light receiving device 91 and the fetal heart collecting device are all connected with the signal processing controller 11, and the luminous light source device 92 irradiates two or more lights with different wavelengths into the abdomen of the pregnant woman; the light receiving device 91 comprises a plurality of light receivers 204, and a primary signal processor connected with the light receivers 204, wherein the primary signal processor is connected with the fetal heart collecting device, the primary signal processor synthesizes a plurality of received light signals related to the fetal blood oxygen saturation degree by using the extra-abdominal noninvasive fetal blood oxygen saturation detecting signal processing method of the invention to output the sum of the light signals to the signal processing controller 11, and the signal processing controller 11 calculates the fetal blood oxygen saturation degree according to the sum of the light signals output by the light receiving device 91 and the fetal heart rate signal collected by the fetal heart collecting device.

The method for processing the extra-abdominal noninvasive fetal blood oxygen saturation signal acquires a plurality of optical signals related to the fetal blood oxygen saturation through the plurality of optical receivers 204, superposes the optical signals to synthesize the sum of the optical signals so as to improve the intensity of the received optical signals, performs correlation analysis on the optical signals acquired by the plurality of optical receivers 204 and fetal heart rate signals acquired simultaneously so as to perform weighted superposition so as to reduce noise signal interference irrelevant to the fetal blood oxygen saturation in the optical signals, and improves the signal-to-noise ratio of the acquired optical signals so as to improve the accuracy and reliability of detection of the extra-abdominal noninvasive fetal blood oxygen saturation detection device. Particularly, when a plurality of received optical signals related to the fetal blood oxygen saturation are respectively subjected to correlation analysis with a fetal heart rate signal, the signals are converted from a time domain to a frequency domain for correlation analysis, and signal spectrum power except the fetal spectrum power is filtered from an optical signal spectrum, so that noise interference is greatly reduced, and the intensity of acquiring the optical signals related to the fetal blood oxygen saturation is improved. In addition, the invention has another improvement that the sensor on the abdomen of the pregnant woman and the fetal blood oxygen detector host are connected by using wireless communication.

Drawings

FIG. 1 is a block diagram of the non-invasive fetal blood oxygen saturation detection device outside the abdomen according to the present invention;

FIG. 2 is a schematic structural diagram of the non-invasive fetal blood oxygen saturation detection apparatus outside the abdomen of the present invention;

FIG. 3 is a schematic structural diagram of a fetal blood oxygen optical signal collecting device according to the present invention;

FIGS. 4-5 are block diagrams of two embodiments of the light receiving device of the present invention;

FIGS. 6-11 are schematic diagrams of the layout structures of a plurality of light receivers and a light source of the fetal blood oxygen optical signal collecting device according to six embodiments of the present invention;

FIGS. 12 to 14 are structural diagrams of three embodiments of the layout structures of the light emitting units of the light emitting source of the light receiving device of the present invention;

FIG. 15 is a schematic structural diagram of a luminescent light source device according to the present invention;

fig. 16 is a structural view of a further embodiment of a light-receiving device of the present invention;

FIG. 17 is a block diagram of one embodiment of a signal processing flow of primary processor 250 shown in FIG. 16;

FIG. 18 is a block diagram of another embodiment of the signal processing flow of primary processor 250 shown in FIG. 16;

FIG. 19 is a block diagram of yet another embodiment of the signal processing flow of primary processor 250 shown in FIG. 16;

fig. 20 is one embodiment of an addition selector of the light receiving device of fig. 16;

fig. 21 is another embodiment of the addition selector of the light receiving device of fig. 16.

Detailed Description

The following further describes an embodiment of the non-invasive fetal blood oxygen saturation detecting device outside the abdomen according to the present invention with reference to the embodiments shown in fig. 1 to 21.

As shown in fig. 1, the extra-abdominal noninvasive fetal blood oxygen saturation detection apparatus according to the present invention generally includes an extra-abdominal fetal oximeter and a signal detection module connected to the extra-abdominal fetal oximeter. The abdominal and external infant oximeter comprises a signal processing controller 11; the signal detection assembly comprises a light-emitting light source device 92 used for irradiating light with two or more different wavelengths into the abdomen of the pregnant woman, a light receiving device 91 used for collecting light signals related to the blood oxygen saturation degree of the fetus from the outside of the abdomen of the pregnant woman, and a reference signal detection device used for collecting any one or more signals of a heart rate signal of the fetus, a heart rate signal of the pregnant woman and a pulse blood oxygen saturation degree light signal of the pregnant woman. The reference signal detection device comprises a fetal heart acquisition device for acquiring fetal heart rate signals from the outside of the abdomen of a pregnant woman, and/or a pregnant woman heart rate acquisition device for acquiring pregnant woman heart rate signals, and/or a pregnant woman pulse oxyhemoglobin saturation acquisition device for acquiring pregnant woman pulse oxyhemoglobin saturation optical signals, wherein the light receiving device 91, the light emitting light source device 92, the fetal heart acquisition device, the pregnant woman heart rate acquisition device and the pregnant woman pulse oxyhemoglobin saturation acquisition device are all connected with the signal processing controller 11; the signal processing controller 11 calculates the fetal pulse oximetry based on one or more of the fetal heart rate signal, the maternal heart rate signal, and the maternal pulse oximetry optical signal from the collected optical signals related to the fetal blood oxygen saturation.

The invention relates to a detection technology for measuring the blood oxygen saturation of the blood flow of a fetus in vitro of a pregnant woman, which does not need any operation deep in the abdomen of the pregnant woman in the detection process, does not need to apply a photoelectric sensor to a specific part of the fetus, and creatively realizes noninvasive detection of the blood oxygen saturation of the fetus outside the abdomen, and the specific solution of the problem of how to convert and process signals is disclosed in the previous invention patent CN201310182965.2 of the inventor and is not repeated.

As shown in fig. 2-3, an embodiment of the extra-abdominal noninvasive fetal blood oxygen saturation detection apparatus of the present invention includes an extra-abdominal fetal oximeter and a fetal blood oxygen optical signal acquisition apparatus 9 connected to the extra-abdominal fetal oximeter; the abdominal and external infant oximeter comprises a signal processing controller 11, and a display module 12 and an operation module 13 which are connected with the signal processing controller 11; the fetal blood oxygen optical signal collecting device 9 comprises an optical sensor mounting mechanism 93, the optical sensor mounting mechanism 93 is integrally provided with a light-emitting light source device 92 and a light receiving device 91 comprising a plurality of light receivers 204, and the light-emitting light source device 92 and the light receiving device 91 are integrated together to form the collecting device for collecting the fetal blood oxygen optical signals. The fetal blood oxygen optical signal acquisition device 9 can tightly wrap the light-emitting light source device 92 and the light receiving device 91 on the abdominal body surface of the pregnant woman in a clinging manner, and can be adjusted according to the moving position of the fetus; preferably, the fetal blood oxygen optical signal collecting device 9 is a soft component which can be fixedly installed with the light emitting light source device 92 and the light receiving device 91 comprising a plurality of light receivers 204 and can be fixed on the abdomen of the pregnant woman to cover the abdomen of the pregnant woman. The optical sensor mounting mechanism 93 of the fetal blood oxygen optical signal collecting device 9 may be a belt attached to the abdomen of the pregnant woman, a wearable abdomen scarf, a bellyband or other devices that can mount the light emitting light source device 92 and the light receiving device 91 including the plurality of light receivers 204 and can be fixed to the abdomen of the pregnant woman. The fetal blood oxygen optical signal acquisition device 9 is connected with the abdominal and external infant oximeter through a communication link 14, and the communication link 14 may be a wired link or a wireless link. The wireless link may employ WIFI, bluetooth, and other wireless communication protocols. The display module 12 may be an LED screen, an LCD screen, or a touch screen, and the operation module 13 may be a keyboard.

Furthermore, the device for detecting the degree of blood oxygen saturation of the fetus without wound outside the abdomen further comprises a fetal heart acquisition device (not shown in the figure), the fetal blood oxygen optical signal acquisition device 9 and the fetal heart acquisition device are combined together to form an abdomen outer child blood oxygen probe, or the fetal heart acquisition device is also integrated on the optical sensor mounting mechanism 93 of the fetal blood oxygen optical signal acquisition device 9 to form the abdomen outer child blood oxygen probe, which is used for acquiring various signals required by the abdomen outer child blood oxygen oximeter, and the abdomen outer child blood oxygen probe is connected with the abdomen outer child blood oxygen oximeter 1 through the communication link 14. For example, an embodiment is that the fetal blood oxygen optical signal acquisition device 9 and the fetal heart acquisition device are two independent acquisition devices, which together form an abdomen-outer fetus blood oxygen probe, the fetal blood oxygen optical signal acquisition device 9 and the fetal heart acquisition device are respectively connected with the abdomen-outer fetus blood oxygen meter 1, the abdomen-outer fetus blood oxygen meter 1 is provided with an optical signal interface connected with the optical receiving device 91, a light-emitting source interface connected with the light-emitting source device 92, and a fetal heart rate detection interface connected with the fetal heart acquisition device, the light-emitting source device 92, the optical receiving device 91 and the fetal heart rate acquisition device are respectively connected with the optical signal interface, the light-emitting source interface and the fetal heart rate detection interface through an optical signal link, a light-emitting source link and a fetal heart rate signal link, which can be in a wired or wireless link manner, the wireless link may employ WIFI, bluetooth, and other wireless communication protocols. For example, another embodiment is that the light-emitting light source device 92 and the light-receiving device 91 of the fetal blood oxygen light signal collecting device 9, and the fetal heart collecting device are integrated on the light sensor mounting mechanism 93 to form an abdomen and outer fetus blood oxygen probe, the abdomen and outer fetus blood oxygen meter 1 is provided with a first wireless transmitting and receiving device, the light signal interface, the light-emitting light source interface, and the fetal heart rate detecting interface of the abdomen and outer fetus blood oxygen meter 1 are respectively connected with the first wireless transmitting and receiving device, the light sensor mounting mechanism 93 is provided with a second wireless transmitting and receiving device, the light-emitting light source device 92, the light-receiving device 91, and the fetal heart collecting device are respectively connected with the second wireless transmitting and receiving device, and are connected with the abdomen and outer fetus blood oxygen meter 1 through links of the second wireless transmitting and. Further, the abdomen-cover infant blood oxygen probe can also comprise a pregnant woman heart rate acquisition device and/or a pregnant woman pulse blood oxygen saturation acquisition device (not shown in the figure).

In one of the improvements of the present invention, the signal processing controller 11 controls the light source device 92 to irradiate two or more lights with different wavelengths into the abdomen of the pregnant woman, the light receiving device 91 includes a plurality of light receivers 204 respectively disposed at a plurality of different positions outside the abdomen of the pregnant woman, the light receiving device 91 collects a plurality of light signals related to the blood oxygen saturation level of the fetus scattered and reflected from the abdomen of the pregnant woman through the plurality of light receivers 204, and outputs the sum of the light signals related to the blood oxygen saturation level of the fetus to the signal processing controller 11 after being superimposed. The light receiving device 91 of the invention comprises a plurality of light receivers 204 respectively arranged at a plurality of different positions outside the abdomen of the pregnant woman, the light receiving device 91 collects a plurality of light signals which are returned from the abdomen of the pregnant woman and are related to the blood oxygen saturation of the fetus, and the light signals are superposed and converged to form a light signal sum which is transmitted to the signal processing controller 11; the signal processing controller 11 calculates the fetal blood oxygen saturation level according to the sum of the optical signals output by the light receiving device 91 and any one or more of the fetal heart rate signal, the maternal heart rate signal and the maternal pulse blood oxygen saturation level optical signal collected from the reference signal detecting device. The light receiving device 91 of the present invention collects a plurality of light signals related to the blood oxygen saturation level of the fetus through the plurality of light receivers 204, superimposes and summarizes the collected plurality of signals and transmits the superimposed and summarized signals to the signal processing controller 11, thereby effectively improving the intensity of the light signals related to the blood flow of the fetus in the received signals. The optical receiver 204 is a silicon photodiode, an avalanche photodiode, a photomultiplier tube or other photoelectric conversion devices; the light emitting module 12 includes at least two light sources with different wavelengths, which may be red light at 500 nm to infrared light at 1000 nm, preferably 660 nm, 740 nm, 880 nm, 940 nm, and the light emitting source is an LED or a laser or other light emitting sources.

As shown in fig. 4-5, the light receiving device 91 includes a plurality of light receivers 204 and an adder connected to the plurality of light receivers 204, and the adder is connected to the signal processing controller 11 of the abdominal-outer infant oximeter. Each optical receiver 204 receives the optical signal which is returned from the abdomen of the pregnant woman and related to the blood oxygen saturation of the fetus, and converts each optical signal into a plurality of paths of electric signals, the adder superposes the plurality of paths of electric signals and outputs the sum of the optical signals which are related to the blood oxygen saturation of the fetus to the signal processing controller 11, the optical receiving device 91 is realized through the plurality of optical receivers 204 and the adder, the structure is simple, the cost is low, and the existing abdomen and cover infant oximeter is not required to be improved.

As shown in fig. 4, in an embodiment of the light receiving device 91 of the present invention, the light receiving device 91 includes a plurality of light receivers 204, a plurality of amplifiers respectively connected to the plurality of light receivers 204, the plurality of amplifiers are connected to an adder, and the adder is connected to the signal processing controller 11 of the abdominal and external infant oximeter through a digital-to-analog converter. Each optical receiver 204 receives the optical signal related to the blood oxygen saturation level of the fetus returned from the abdomen of the pregnant woman, converts each optical signal into a plurality of paths of electrical signals, and the plurality of paths of electrical signals are added together by an adder after being amplified by an amplifier and then are output to the signal processing controller 11 after the sum of the optical signals of the digital-to-analog converter.

As shown in fig. 5, in another embodiment of the light receiving device 91 of the present invention, the light receiving device 91 comprises a plurality of light receivers 204, a plurality of amplifiers respectively connected to the plurality of light receivers 204, a plurality of digital-to-analog converters respectively connected to the plurality of amplifiers, the plurality of digital-to-analog converters being connected to an adder, the adder being connected to the signal processing controller 11 of the abdominal-outer infant oximeter. Each optical receiver 204 converts each optical signal into a plurality of electrical signals, and then amplifies the signals by an amplifier, converts the signals into digital signals by a digital-to-analog converter, and superimposes the digital signals into an optical signal sum by an adder, and outputs the optical signal sum to the signal processing controller 11.

In one of the improvements of the present invention, the fetal blood oxygen optical signal collecting device 9 integrates the light-emitting light source device 92 and the light receiving device 91 including a plurality of light receivers 204, so that not only is the usage thereof convenient, but also the arrangement of the light-emitting light source device 92 and the plurality of light receivers 204 is more reasonable, the paths of collecting scattering and reflection are closer, the light source can be reasonably utilized, and the signal intensity collected by the light receiving device 91 is improved.

Referring to fig. 6, in a preferred embodiment of the fetal blood oxygenation optical signal collecting device 9 of the present invention, the plurality of optical receivers 204 of the optical receiving device 91 and the light emitting source device 92 are mounted on the sensor mounting mechanism 93, and the plurality of optical receivers 204 of the optical receiving device 91 are disposed around the light emitting source 921 of the light emitting source device 92 to form a circle. Preferably, the optical sensor mounting mechanism 93 can form a circular arch to be buckled on the abdomen of the pregnant woman, the light source of the light source device 92 is positioned in the middle of the circular arch and positioned in the middle of the top side of the abdomen of the pregnant woman, the plurality of light receivers 204 of the light receiving device 91 are encircled into a circle on the lateral side of the abdomen of the pregnant woman, the light source and the plurality of light receivers 204 form a circular arch, the plurality of light receivers 204 of the light receiving device 91 and the light source 921 of the light source device 92 are reasonably arranged, the light source can be reasonably utilized, and the signal intensity collected by the light receiving device 91 is improved.

Referring to fig. 7, in another preferred embodiment of the fetal blood oxygenation optical signal collecting device 9 of the present invention, the plurality of light receivers 204 of the light receiving device 91 are disposed around the light emitting source 921 of the light emitting source device 92 to form a square.

As shown in fig. 8-11, in some embodiments, the light receivers 204 of the light receiving device 91 form an array of 1 i rows by j columns and are disposed on one side of the light emitting source 921 of the light emitting source device 92, where i and j are integers greater than 0; or the plurality of light receivers 204 of the light receiving device 91 form an array of 2 i rows by j columns and are respectively arranged at two sides of the light emitting source 921 of the light emitting source device 92, and i and j are integers greater than 0.

Further, in another preferred embodiment of the fetal blood oxygen optical signal collecting device 9 of the present invention, the fetal blood oxygen optical signal collecting device 9 further comprises a conducting switch controlled by a signal generated by a pulse timing sequence emitted by the light emitting source device 92, and the optical signal received by each optical receiver 204 of the light receiving device 91 is converted into an electrical signal and then passes through the conducting switch, so that the light emitting of the light emitting source device 92 and the optical signal received by the conducting switch are synchronized, and only the optical signal within a narrow pulse time synchronized with the light emitting of the light emitting source device 92 can be sent to the analog-to-digital converter of the light receiving device 91 to be converted into a digital signal for further processing.

In one of the improvements of the present invention, the light source device 92 of the present invention includes a light source 921 and a light source driver connected to the light source 921. The light source driver is connected with the signal processing controller, and the light source driver drives the light emitting light source 921 to emit pulsed light with frequency higher than 20Hz under the control of the signal processing controller, and the duty ratio of the pulse is less than 40%. The preferred frequency range of the pulsed light is 400Hz to 5000Hz, but does not include frequencies of 50Hz, 60Hz and their integer multiples. The light source device 92 of the invention adopts the pulse light signal with smaller duty ratio, so that the average light power received by the human body is greatly smaller than the instantaneous maximum light power, thereby ensuring the safety of the human body, improving the signal intensity and solving the problem that the pregnant woman and the fetus are possibly injured by the overlarge light power. The light source driver of the present embodiment may be used for the light emitting source 921 having a single first light emitting unit and a single second light emitting unit, and may also be used for the light emitting source 921 having a plurality of first light emitting units and a plurality of second light emitting units.

In one of the improvements of the present invention, the light source device of the present invention includes a light source 921 and a light source driver connected to the light source 921, where the light source 921 includes a plurality of first light emitting units and a plurality of second light emitting units, each of the plurality of first light emitting units is capable of emitting red light or infrared light of a first wavelength, each of the plurality of second light emitting units is capable of emitting red light or infrared light of a second wavelength, the first wavelength is different from the second wavelength, the number of the first light emitting units is the same as the number of the second light emitting units, the plurality of first light emitting units and the plurality of second light emitting units are arranged in a row light source array, and the plurality of first light emitting units and the plurality of second light emitting units are alternately turned on under the control of the light source driver. The first light-emitting units and the second light-emitting units in the row-column light source array may be equally spaced or unequally spaced, and preferably, the spacing of the light-emitting units in the row-column light source array is equal. The luminous light source device 92 of the invention adopts a plurality of first luminous units and a plurality of second luminous units, and the plurality of first luminous units and the plurality of second luminous units are arranged into a row-column light source array with equal intervals, so that a large-range multipath is realized to increase the luminous power of the light source, meanwhile, the illumination is not a little, the received optical signal related to the blood oxygen saturation of the fetus is greatly enhanced compared with the original device, but the received optical power of the abdominal skin unit area of the pregnant woman is very small or not increased. Preferably, the light source device 92 includes at least 2 first light emitting units and at least 2 second light emitting units. The first light emitting unit and the second light emitting unit are LEDs, lasers or other light sources capable of emitting red light or infrared light, preferably LEDs or lasers capable of emitting red light of 600 nm to infrared light of 950 nm, and if the first wavelength is red light, the second wavelength is infrared light, and if the first wavelength is infrared light, the second wavelength is red light. The first wavelengths of the red light or the infrared light emitted by the plurality of first light emitting units can be preferably identical, but are difficult to achieve in practice, and therefore, the first wavelengths of the red light or the infrared light emitted by the plurality of first light emitting units are substantially identical within a small deviation range, and all of them belong to the protection scope of the present application. Likewise, the second wavelength of the red or infrared light emitted by the plurality of second light emitting units is also similar.

As shown in fig. 12, the light emitting source 921 of the light emitting source device 92 includes a first row light source array in which a plurality of first light emitting cells are arranged at equal or unequal intervals to form m × n, a second row light source array in which a plurality of second light emitting cells are arranged at equal or unequal intervals to form m × n, n is an integer greater than 1, and m is an integer greater than or equal to 1. The first light emitting unit is a red light LED 102, R in the figure represents red light, the first row light source array is a red light LED array formed by red light LEDs, the second light emitting unit is an infrared light LED 104, IR in the figure represents infrared light, and the second row light source array is an infrared light LED array formed by infrared light LEDs.

As shown in fig. 13, the light source of the light source device includes a row and column light source array formed by arranging a plurality of first light emitting units and a plurality of second light emitting units at equal or unequal intervals, each row of the row and column light source array is a first light emitting unit array formed by the first light emitting units or a second light emitting unit array formed by the second light emitting units, the first light emitting unit array and the second light emitting unit array are alternately arranged, n is an integer greater than 1, m is an integer greater than or equal to 1, however, the light paths of the red light or the infrared light with two different wavelengths reaching the fetus through the abdomen of the pregnant woman are closer than the light paths in the manner of fig. 12. Obviously, the first light emitting units and the second light emitting units may be arranged in an alternating manner in rows, that is, the first light emitting units and the second light emitting units are arranged at equal intervals or at unequal intervals to form a row-column light source array of 2 × m rows and n columns, each row of the row-column light source array is a first light emitting unit row formed by the first light emitting units or a second light emitting unit row formed by the second light emitting units, the first light emitting unit row and the second light emitting unit row are arranged alternately, n is an integer greater than or equal to 1, and m is an integer greater than 1.

As shown in fig. 14, in the preferred embodiment of the light-emitting light source device of the present invention, in the row-column light source array formed by a plurality of first light-emitting units and a plurality of second light-emitting units, the first light-emitting units and the second light-emitting units are alternately arranged, so that the first light-emitting units and the second light-emitting units are alternately arranged in each row of the row-column light source array, and the first light-emitting units and the second light-emitting units are also alternately arranged in each column of the row-column light source array, so that the light paths of two red lights or infrared lights with different wavelengths reaching the fetus through the abdomen of the pregnant woman are closer than those in fig. 13, thereby greatly improving the intensity and accuracy of the signals collected.

Further, as shown in fig. 15, in the preferred embodiment of the luminescent light source device of the present invention, a light diffusing lens 922 for diffusing an irradiation area is provided outside a row-column light source array in which a plurality of first light emitting units and a plurality of second light emitting units of the luminescent light source 921 are arranged, so that light radiation per unit irradiation area is not increased when increasing the luminous power of the light emitting units. Preferably, the light diffusion lens 922 is a concave lens, and the distance between the concave lens and the first light emitting unit and the distance between the concave lens and the second light emitting unit are greater than 0; or, the light diffusion lens is a convex lens, and the distance between the concave lens and the first light emitting unit and the distance between the concave lens and the second light emitting unit are greater than 0 and less than or equal to the focal length of the convex lens.

Further, the preferred embodiment of the fetal blood oxygenation optical signal acquisition device of the present invention combines the optical receiver device 91 of the present invention, which includes a plurality of optical receivers 204, with the light emitting source device 92 of the row-column light source array layout. As a preferred mode, the light receiving device 91 and the light source device 92 are installed on the light sensor installation mechanism 93, the light source of the light source device 92 comprises a row light source array composed of a plurality of first light emitting units and a plurality of second light emitting units, the first light emitting units and the second light emitting units are alternately arranged in the row light source array, so that the first light emitting units and the second light emitting units are alternately arranged in each row of the row light source array and the first light emitting units and the second light emitting units are also alternately arranged in each column of the row light source array, and the plurality of light receivers 204 of the light receiving device 91 are arranged around the light source device 92 to form a circle, the light sensor installation mechanism 93 can form a circular arch to be buckled on the abdomen of the pregnant woman, the light source of the light source device 92 is located in the middle of the top side of the abdomen of the pregnant woman, the plurality of light receivers 204 of the light receiving device 91 are encircled into a circle on the side of the abdomen of the pregnant woman, the light emitting source and the plurality of light receivers 204 form a dome shape. The illumination of the light source and the collection of the light receiver 204 are both multipoint and do not require one-to-one correspondence, so that the unit area is enlarged, and the light paths of the red light or the infrared light with two different wavelengths reaching the fetus through the abdomen of the pregnant woman are close, so that the intensity of the light signals related to the blood flow of the fetus in the received signals is greatly improved.

As shown in fig. 16, according to another improvement of the present invention, the light receiving device 91 of the present invention includes a plurality of light receivers 204, a primary signal processor 250 connected to the plurality of light receivers 204, the primary signal processor 250 includes an interface for receiving a fetal heart rate signal, and is connected to the fetal heart rate collecting device, the primary signal processor 250 receives a plurality of light signals related to the fetal blood oxygen saturation through the plurality of light receivers 204, and obtains the fetal heart rate signal collected simultaneously through the fetal heart rate collecting device, and the primary signal processor 250 performs correlation analysis on the received plurality of light signals related to the fetal blood oxygen saturation and the fetal heart rate signal respectively to obtain correlation coefficients of the light signals; obtaining a weighting coefficient corresponding to each optical signal based on the correlation coefficient; and superposing the plurality of optical signals according to respective weighting coefficients to obtain an optical signal sum.

The invention also provides a signal processing method for detecting fetal blood oxygen saturation without wound outside the abdomen, which synthesizes a plurality of received optical signals containing fetal blood oxygen saturation information into an optical signal sum to improve the intensity of the optical signals related to the fetal blood oxygen saturation and remove noise interference to improve the signal-to-noise ratio, and can be used for an optical receiving device 91, and the method comprises the following steps:

respectively carrying out correlation analysis on a plurality of received optical signals related to the fetal blood oxygen saturation and a fetal heart rate signal to obtain correlation coefficients of the optical signals; obtaining a weighting coefficient corresponding to each optical signal based on the correlation coefficient; and superposing the plurality of optical signals according to respective weighting coefficients to obtain an optical signal sum. Wherein, the step of obtaining the weighting coefficient corresponding to each optical signal based on the correlation coefficient is: if the correlation coefficient of the optical signal is lower than a preset correlation threshold value, discarding the optical signal, namely, the weighting coefficient is 0; if the correlation coefficient is higher than a preset correlation threshold, obtaining a weighting coefficient according to the correlation coefficient, wherein the greater the correlation coefficient is, the greater the weighting coefficient is, and the weighting coefficient is greater than 0 and less than 1; then, the plurality of optical signals are superimposed according to the respective weighting coefficients to obtain an optical signal sum, for example, the plurality of optical signals are multiplied by the respective weighting coefficients and then superimposed to obtain an optical signal sum. The method for processing the extra-abdominal noninvasive fetal blood oxygen saturation signal acquires a plurality of optical signals related to the fetal blood oxygen saturation through the plurality of optical receivers 204, superposes the optical signals to synthesize the sum of the optical signals so as to improve the intensity of the received optical signals, performs correlation analysis on the optical signals acquired by the plurality of optical receivers 204 and fetal heart rate signals acquired simultaneously so as to perform weighted superposition to remove noise signal interference irrelevant to the fetal blood oxygen saturation in the optical signals, and improves the signal-to-noise ratio of the acquired optical signals so as to improve the accuracy and reliability of detection of the extra-abdominal noninvasive fetal blood oxygen saturation detection device.

The method for processing the extraabdominal noninvasive fetal blood oxygen saturation detection signal can be used on an optical receiving device 91 of the extraabdominal noninvasive fetal blood oxygen saturation detection device, a plurality of received optical signals related to the fetal blood oxygen saturation are selected and superposed to obtain an optical signal sum, noise interference is removed, the signal to noise ratio is improved, the optical signal sum related to the fetal blood oxygen saturation is sent to a signal processing controller 11 of an extraabdominal fetal oximeter 1, and the optical signal sum and a fetal heart rate signal are analyzed and calculated by the signal processing controller 11 to obtain the fetal blood oxygen saturation. Of course, the signal processing controller 11 may further perform analysis and calculation based on the sum of the optical signals and the collected maternal heart rate, and/or the maternal optical signal, and/or the fetal heart rate signal to obtain the blood oxygen saturation level of the fetus, and the calculation method of the blood oxygen saturation level of the fetus is described in another patent CN201310182965.2 of the inventor, and is not described herein again. It should be noted that the signal processing method for detecting the blood oxygen saturation level of the fetus without wound outside the abdomen of the invention can also be processed by the signal processing controller 11, and the signal processing controller 11 receives a plurality of optical signals and then synthesizes a summation of the optical signals, but this will greatly increase the complexity of the system.

As shown in fig. 16, the light receiving device 91 of the present invention includes a plurality of light receivers 204, a plurality of amplifiers respectively connected to the plurality of light receivers 204, a plurality of digital-to-analog converters respectively connected to the plurality of amplifiers, and a signal primary processor 250 connected to the plurality of digital-to-analog converters, the signal primary processor 250 being connected to an output terminal of the fetal heart collecting device. Each optical receiver 204 receives optical signals from the abdomen of the pregnant woman and converts the optical signals into a plurality of paths of electric signals, the electric signals are processed into a plurality of paths of digital signals by an amplifier and an analog-to-digital converter, and the digital signals are synthesized into a received optical signal sum 256 after being processed by a signal primary processor 250.

One embodiment of the signal primary processor 250 is shown in fig. 16 and includes a plurality of signal analyzers 252 and an addition selector 254 connected to the plurality of signal analyzers 252, wherein the plurality of signal analyzers 252 perform correlation analysis and the addition selector 254 performs selective superposition of signals. Certainly, the signal primary processor 250 may be a single chip microcomputer, the signal processing method for detecting the blood oxygen saturation level of the non-invasive fetus outside the abdomen of the present invention is implemented by software, the corresponding functions of the signal analyzer 252 and the addition selector 254 are implemented by software, and the single chip microcomputer executes the corresponding software to analyze, process and superimpose a plurality of optical signals to realize the synthesis of the sum of the optical signals. The fetal heart rate sensor of the fetal heart acquisition device can be a Doppler ultrasonic fetal heart sound sensor or a fetal electrocardio sensor consisting of electrodes or other fetal heart rate sensors. As another embodiment, the signal primary processor 250 may be a single chip microcomputer, instead of the adder shown in fig. 4 to 5, to implement the embodiment shown in fig. 4 to 5, and directly perform signal superposition through software.

Fig. 17 shows an example of a process of signal analysis in the time domain by the signal analyzer 252, where the signal analyzer 252 is a time domain signal analyzer, and performs correlation analysis on each received optical signal related to the fetal blood oxygen saturation and the received fetal heart rate signal in the time domain to obtain a correlation coefficient of each optical signal. Referring to fig. 17 in detail, the process of synthesizing the received light signal sum 256 by superimposing the digital signal weights of the multiple optical signals in the extra-abdominal noninvasive fetal blood oxygen saturation detection signal processing method of the present invention includes the following steps:

(620) acquiring an optical signal received by an optical receiver, converting the optical signal received by the optical receiver into an electrical signal, processing the electrical signal by an amplifier and a digital-to-analog converter, and converting the electrical signal into a digital signal to obtain an optical signal related to the blood oxygen saturation of the fetus;

(630) in parallel with step (620), acquiring a fetal heart rate signal received by a fetal heart rate acquisition device;

(622) the correlation analysis of the optical signals and the fetal heart rate signals is carried out in a time domain, the algorithm of the correlation analysis belongs to the prior art, and is recorded in a general mathematical manual, and is not repeated;

(624) calculating a correlation coefficient A through correlation analysis;

(626) judging whether the correlation coefficient A exceeds a preset threshold value X, if so, going to a step 628, and if not, going to a step 632;

(628) obtaining a weighting coefficient M according to the correlation coefficient A, wherein the weighting coefficient M is more than 0 and less than 1, and then turning to the step 634 below;

(632) setting the weighting factor M to 0, and then proceeding to step 634 below;

(634) the weighted data E is sent to the addition selector 254 by multiplying the optical signal related to the fetal blood oxygen saturation level by the weighting coefficient M.

Fig. 18 is an example of a process of performing signal analysis in the frequency domain by the signal analyzer 252, where the signal analyzer 252 is a frequency domain signal analyzer, and converts each received optical signal related to the fetal blood oxygen saturation from the time domain to the frequency domain to obtain an optical signal spectrum, and converts each received fetal heart rate signal from the time domain to the frequency domain to obtain a fetal frequency domain optical power spectrum, and performs correlation analysis on the optical signal spectrum in the frequency domain and the fetal frequency domain optical power spectrum to obtain a correlation coefficient of each optical signal. Referring to fig. 18 in detail, the process of synthesizing the received light signal sum 256 by weighting and superimposing the multiple paths of digital signals in the extra-abdominal noninvasive fetal blood oxygen saturation detection signal processing method of the present invention includes the following steps:

(720) acquiring an optical signal received by the optical receiver, converting the optical signal received by the optical receiver into an electrical signal, processing the electrical signal by the amplifier and the digital-to-analog converter, converting the electrical signal into a digital signal to obtain an optical signal related to the blood oxygen saturation of the fetus, and then turning to step 722 below;

(722) converting the optical signal related to the fetal blood oxygen saturation from the time domain to the frequency domain to obtain an optical signal spectrum, and then, converting to step 724;

(740) in parallel with step 720, acquiring a fetal heart rate signal received by the fetal heart rate acquisition device, and then proceeding to step 742 below;

(742) converting the input fetal heart rate signal from the time domain to the frequency domain to obtain a fetal frequency domain optical power spectrum, and then converting to step 724 below the fetal frequency domain optical power spectrum;

(724) carrying out correlation analysis on the optical signal spectrum related to the fetal blood oxygen saturation in a frequency domain and a fetal frequency domain optical power spectrum;

(726) calculating a relative value B of the optical signal spectrum and the optical power spectrum of the fetal frequency domain in a frequency domain through correlation analysis to serve as a correlation coefficient;

(728) judging whether the relative value B exceeds a preset threshold value Y, if so, turning to the next step 730, and if not, turning to the next step 744;

(730) restoring the optical signal spectrum from the frequency domain back to the time domain, and then proceeding to step 732 below;

(732) weighting according to the relative value B to obtain a weighting coefficient M, wherein the weighting coefficient M is more than 0 and less than 1, and then proceeding to a step 734 below;

(744) restoring the optical signal spectrum signal from the frequency domain back to the time domain, and then turning to the step 746 below, although the step 744 may also be omitted;

(746) setting the weighting factor M to 0, and proceeding to step 734 below;

(734) the optical signal relating to the fetal blood oxygen saturation level is weighted by a weighting coefficient M, and the weighted data F is sent to the addition selector 254.

Fig. 19 is another example of the process of signal analysis in the frequency domain by the signal analyzer 252, which converts each received optical signal related to the fetal blood oxygen saturation from the time domain to the frequency domain to obtain an optical signal spectrum, converts the received fetal heart rate signal from the time domain to the frequency domain to obtain a fetal frequency domain optical power spectrum, performs correlation analysis on the optical signal spectrum in the frequency domain and the fetal frequency domain optical power spectrum to obtain correlation coefficients of each optical signal, filters out signal spectrum power other than the fetal frequency spectrum power from the optical signal spectrum to obtain a filtered optical signal spectrum, so as to remove noise signal interference unrelated to the fetal blood oxygen saturation in the optical signal, and restores the filtered optical signal spectrum from the frequency domain back to the time domain to obtain a filtered optical signal as a weighted-superimposed optical signal. Specifically, referring to fig. 19, the process of synthesizing the received light signal sum 256 by overlapping the weights of the multiple digital signals in the method for processing the extraabdominal noninvasive fetal blood oxygen saturation detection signal according to the present invention includes the following steps:

(722) converting the optical signal related to the blood oxygen saturation level of the fetus from the time domain to the frequency domain to obtain an optical signal spectrum, and then, converting to the following step 724;

(724) carrying out correlation analysis and comparison on the optical signal spectrum related to the blood oxygen saturation of the fetus in a frequency domain and the optical power spectrum of the fetus frequency domain;

(728) judging whether the relative value B exceeds a preset threshold value Y, if so, turning to the next step 750, and if not, turning to the next step 744;

(750) filtering out the signal spectrum power except the fetal frequency domain optical power spectrum from the optical signal spectrum to obtain a filtered optical signal spectrum, which can be implemented by a frequency domain filter or a software mode, and then proceeding to step 730 below

(730) Restoring the spectrum of the filtered optical signal from the frequency domain back to the time domain to obtain a filtered optical signal as a weighted and superimposed optical signal, and then proceeding to step 734 below;

(744) restoring the optical signal spectrum from the frequency domain back to the time domain, and then proceeding to step 746 below;

(746) multiply the weighting factor M to 0 and then go to step 734 below;

(734) the filtered optical signal relating to the fetal blood oxygen saturation level is weighted by a weighting coefficient M, and the weighted data F is sent to the addition selector 254.

Fig. 18 differs from fig. 19 in that, after the frequency domain signal is determined to exceed the preset threshold value Y at step 728, fig. 18 directly performs inverse conversion to restore the time domain signal at step 730. Fig. 19 shows that the signal irrelevant to the optical power spectrum of the fetal frequency domain is filtered and then input to step 730 to perform inverse transformation to restore the time domain signal.

In fig. 18 and 19, a fast fourier transform formula or a Z transform formula may be used as a mathematical transform formula for converting the signal from the time domain to the frequency domain in step 722, and in addition, laplace transform may also be used for converting the signal from the time domain to the frequency domain, and a manner of converting the time domain to the frequency domain belongs to the prior art and is not described in detail.

The mathematical transform formula for converting the signal from the frequency domain back to the time domain in step 730 in fig. 18 and 19 may correspondingly adopt a fast inverse fourier transform formula and an inverse Z transform formula or an inverse laplace transform, and the way of converting the frequency domain back to the time domain belongs to the prior art and is not described in detail.

Referring to fig. 16, 20-21, signal primary processor 250 also includes a time-frequency converter for converting the digital signal from the time domain to the frequency domain and/or a time-frequency inverse converter for restoring the digital signal from the frequency domain to the time domain. The signal analyzer 252 of the signal primary processor 250 labels weighting coefficients for each path of digital signals respectively based on the correlation between the fetal heart rate signal and the digital signals in the frequency domain or the time domain, the addition selector 254 performs the superposition processing according to the weighting coefficients, and the addition selector 254 may be a linear adder or an optical signal selector.

Fig. 20 is a flowchart of an example of the addition selector 254 in fig. 16. The signal primary processor 250 includes an add selector 254, and the add selector 254 is a linear adder that linearly adds the plurality of digital signals output by the optical receiver 204 and analyzed and processed by the signal analyzer 252 to synthesize a received optical signal sum 256. Specifically, the

signals

802, 804, 806 produced by each signal analyzer 252 are combined into a linear combiner for linear combination to produce the received light signal sum 256. The received light signal sum 256 will be sent to the abdominal and external infant oximeter 1 via communication link 14. The input signal to the linear adder of the signal primary processor 250 is either data E generated by a time domain signal analyzer or data F generated by a frequency domain signal analyzer.

Fig. 21 is another example of the flow of the addition selector 254 in fig. 16. The signal primary processor 250 includes an addition selector 254, the addition selector 254 is an optical signal selector, and selects one path of the multiple paths of digital signals output from the optical receiver 204 and analyzed and processed by the signal analyzer 252 as a received light signal sum 256; or select multiple digital signals from them and add them to form a received light signal sum 256. Specifically, the

signals

802, 804, 806 produced by each signal analyzer are input into an optical signal selector for further screening and superposition. The optical signal selector 810 selects one or more signals to produce the received optical signal sum 256 based on a comparison of all

signals

802, 804, 806, knowledge of the location of each optical receiver 204 in fig. 6, 7, 16, and other knowledge related to the fetal blood oxygen saturation. The received light signal sum 256 will be sent to the abdominal and external infant oximeter 1 via communication link 14. The input signal of the optical signal selector of the primary signal processor 250 is data E generated by a time domain signal analyzer or data F generated by a frequency domain signal analyzer, and the optical signal selector selection condition of the primary signal processor 250 includes a blood oxygen saturation signal state and/or a position signal state.

The invention can be used for the fetus with poor hypoxia heart rate and the fetus with normal heart rate, can be detected in a hospital, and can also be transplanted and expanded to remote perinatal monitoring supported by mobile internet, such as remote detection at home. The invention can be combined with the prior Electronic Fetal Monitor (EFM) to realize the more comprehensive signal processing of the novel Fetal monitoring equipment.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.

Claims

1. A method for processing a fetal blood oxygen saturation detection signal without wound outside the abdomen is characterized in that a plurality of received optical signals related to the fetal blood oxygen saturation are synthesized into an optical signal sum, and the method comprises the following steps:

step A: respectively carrying out correlation analysis on a plurality of received optical signals related to the fetal blood oxygen saturation and collected by a plurality of optical receivers arranged at a plurality of different positions outside the abdomen of the pregnant woman and a fetal heart rate signal to obtain correlation coefficients of the optical signals;

2. The extra-abdominal noninvasive fetal blood oxygen saturation detection signal processing method according to claim 1, wherein step B comprises:

if the correlation coefficient of the optical signal is lower than a preset correlation threshold value, the weighting coefficient is 0; and if the correlation coefficient is higher than a preset correlation threshold value, obtaining a weighting coefficient according to the correlation coefficient, and superposing the plurality of optical signals according to the respective weighting coefficients to obtain an optical signal sum.

3. The extra-abdominal noninvasive fetal blood oxygen saturation detection signal processing method according to claim 1, wherein step a comprises: and carrying out correlation analysis on each received optical signal related to the fetal blood oxygen saturation and the received fetal heart rate signal in a time domain to obtain a correlation coefficient of each optical signal.

4. The extra-abdominal noninvasive fetal blood oxygen saturation detection signal processing method according to claim 1, wherein step a comprises:

and converting each received optical signal related to the fetal blood oxygen saturation from a time domain to a frequency domain to obtain an optical signal spectrum, converting the received fetal heart rate signal from the time domain to the frequency domain to obtain a fetal frequency domain optical power spectrum, and performing correlation analysis on the optical signal spectrum in the frequency domain and the fetal frequency domain optical power spectrum to obtain a correlation coefficient of each optical signal.

5. The extra-abdominal noninvasive fetal blood oxygen saturation detection signal processing method according to claim 4, wherein the step A further comprises:

and filtering out signal spectrum power except the fetal spectrum power from the optical signal spectrum to obtain a filtered optical signal spectrum, and restoring the filtered optical signal spectrum from a frequency domain to a time domain to obtain a filtered optical signal serving as a weighted and superposed optical signal.

6. The extra-abdominal noninvasive fetal blood oxygen saturation detection signal processing method according to any one of claims 1 to 5, characterized by further comprising the step D of: and analyzing and calculating the sum of the optical signals related to the blood oxygen saturation of the fetus and the acquired pregnant woman heart rate, and/or pregnant woman optical signals, and/or fetus heart rate signals to obtain the blood oxygen saturation of the fetus.

7. An optical receiving device for detecting the blood oxygen saturation of a fetus without wound outside the abdomen, which is characterized in that: the method comprises a plurality of light receivers, and a signal primary processor connected with the plurality of light receivers, wherein the signal primary processor comprises an interface for receiving a fetal heart rate signal, and synthesizes a plurality of received light signals related to the fetal blood oxygen saturation into a light signal sum through the extraabdominal noninvasive fetal blood oxygen saturation detection signal processing method of any one of claims 1 to 5.

8. The light receiving device according to claim 7, wherein: the signal primary processor comprises a plurality of signal analyzers and an addition selector connected with the signal analyzers, the signal analyzers respectively analyze the correlation coefficients of the optical signals related to the blood oxygen saturation of the fetus and the heart rate signals of the fetus, which are acquired by the plurality of optical receivers, and the addition selector superposes the weights of the plurality of paths of digital signals according to the analysis results of the signal analyzers to synthesize the sum of the optical signals.

9. The light receiving device according to claim 8, wherein: the signal analyzer is a time domain signal analyzer or a frequency domain signal analyzer.

10. The light receiving device according to claim 8, wherein: the addition selector is a linear adder, and the linear adder linearly adds the multi-channel digital signals processed by the signal analyzer into a synthesized optical signal sum; or, the addition selector is an optical signal selector, and the optical signal selector selects one path from the multiple paths of digital signals processed by the signal analyzer as an optical signal sum, or selects multiple paths of digital signals from the multiple paths of digital signals and superposes the multiple paths of digital signals to form the optical signal sum.

11. The light receiving device according to claim 7, wherein: the signal primary processor is a singlechip.

12. The utility model provides a there is not fetal oxyhemoglobin saturation detection device of wound outside abdomen, is including the outer child oximetry of abdomen that has signal processing controller, luminous light source device, be used for gathering the light signal's that is relevant with fetal oxyhemoglobin saturation light receiving arrangement outside the pregnant woman's abdomen for gather fetal heart rate signal's fetal heart collection system, luminous light source device, light receiving arrangement and fetal heart collection system all are connected its characterized in that with signal processing controller:

the light source device irradiates two or more than two lights with different wavelengths into the abdomen of the pregnant woman;

the light receiving device comprises a plurality of light receivers, a signal primary processor connected with the plurality of light receivers, the signal primary processor is connected with the fetal heart collecting device, the primary processor synthesizes a plurality of received light signals related to the fetal blood oxygen saturation degree into a light signal sum and outputs the sum to the signal processing controller by the extraabdominal noninvasive fetal blood oxygen saturation degree detection signal processing method as claimed in any one of claims 1-5,

the signal processing controller calculates the fetal blood oxygen saturation according to the sum of the optical signals output by the optical receiving device and the fetal heart rate signal acquired by the fetal heart rate acquisition device.