Frequency-domain near infrared spectrum measurement module and frequency-domain near infrared spectrum equipment

Abstract

The utility model relates to the technical field of brain imaging, in particular to a frequency-domain near-infrared spectrum measurement module and frequency-domain near-infrared spectroscopy device.The frequency-domain near-infrared spectrum measurement module comprises a detection unit and a processing unit, the detection unit is used for making direct contact with the head of a user, emitting detection light to detected tissue and receiving detection signals formed after being reflected by the detected tissue, and the processing unit is used for processing the detection signals; amplitude data and phase data of the detection signal are extracted, and the amplitude data and the phase data are sent to the processing unit after analog-to-digital conversion; and the processing unit is used for calculating optical parameters of the detected tissue based on the converted amplitude data and phase data, and wirelessly transmitting the optical parameters to the target main control unit. Amplitude and phase detection functions are completed by the front-end measurement module in advance, the use of a high-speed ADC and a mixer is avoided, the system complexity is reduced, signal transmission between the measurement module and the main control unit depends on wireless communication, excessive cable connection is not needed, and the brain activity monitoring system is suitable for brain activity monitoring requirements in a dynamic scene.

Description

Technical Field

[0001] This utility model relates to the field of brain imaging technology, and in particular to a frequency domain near-infrared spectroscopy measurement module and a frequency domain near-infrared spectroscopy device. Background Technology

[0002] In the field of brain imaging technology, functional near-infrared spectroscopy (fNIRS) is a technique that detects brain activity using near-infrared light. Its working principle is based on detecting changes in the characteristics of light emitted from a light source and the light reflected or transmitted by tissues to infer the concentration distribution of oxyhemoglobin (oxy-Hb) and deoxyhemoglobin (deoxy-Hb). More detailed analysis of the light signal can provide richer optical parameter data, thereby enabling more accurate detection of brain activity.

[0003] Depending on the measurement method, fNIRS can be divided into three modes:

[0004] Continuous wave (CW) equipment: It only measures changes in light intensity and can detect relative changes in blood oxygen concentration, but cannot provide absolute values;

[0005] Frequency domain (FD) devices: By measuring the amplitude attenuation and phase shift of modulated light, they can obtain the optical absorption and scattering coefficients of tissues, enabling the measurement of absolute blood oxygen concentration; (They can provide absolute values, but are not wearable).

[0006] Time-domain (TD) devices: By detecting the time distribution of photon arrival, the accuracy of optical parameter measurements is further improved.

[0007] CW-fNIRS demonstrates significant advantages in applications such as sports rehabilitation due to its lower cost and adaptability to wearable devices. However, a limitation of CW-fNIRS is that it can only provide relative changes in blood oxygen concentration, restricting its application in scenarios requiring high-precision data. In contrast, FD and TD devices can provide absolute parameter values ​​with higher accuracy, and are therefore considered an important direction for the development of fNIRS.

[0008] However, most existing FD-fNIRS (frequency-domain near-infrared spectroscopy) systems are built on benchtop devices, requiring large external benchtop equipment for core functional modules (such as signal modulation and signal analysis units). Although some designs attempt to make the light source and detection modules partially wearable, the overall system still cannot escape the dependence on benchtop equipment. For example, the modulation light source signal is usually provided by a signal generator, and signal processing relies on network analyzers or computers. This design results in bulky equipment, restricts user movement in dynamic scenes, and fails to meet practical application needs. Utility Model Content

[0009] The purpose of this invention is to provide at least one frequency-domain near-infrared spectroscopy measurement module and frequency-domain near-infrared spectroscopy device, which can at least solve the technical problem of the large size of FD-fNIRS devices and the limited activity of users in dynamic scenes, and at least achieve miniaturization, low power consumption and high integration of FD-fNIRS devices, thereby improving the situation of limited activity of users in dynamic scenes.

[0010] To address the aforementioned technical problems, at least one embodiment of this application provides a frequency-domain near-infrared spectroscopy measurement module, comprising: a detection unit and a processing unit.

[0011] The detection unit is used to make direct contact with the user's head, emit detection light to the tissue to be tested on the user's head, receive the detection signal formed after the detection light is reflected by the tissue to be tested, extract the amplitude data and phase data of the detection signal, and send the amplitude data and phase data to the processing unit after analog-to-digital conversion.

[0012] The processing unit is used to calculate the optical parameters of the tested tissue based on the amplitude data and phase data converted into digital signals, and to transmit the optical parameters to the target main control unit wirelessly.

[0013] In some optional embodiments, the detection unit includes an optical signal modulation circuit, an optical signal detection circuit, an electrical signal detection circuit, and an analog-to-digital conversion circuit.

[0014] The optical signal modulation circuit is used to generate a modulation signal, which is used to drive the light source to generate the detection light and is also used as a reference signal input to the electrical signal detection circuit.

[0015] The optical signal detection circuit is used to receive the detection signal and send the detection signal to the electrical signal detection circuit;

[0016] The electrical signal detection circuit is used to extract the phase data and amplitude data of the probe signal based on the reference signal, and send the amplitude data and phase data to the analog-to-digital conversion circuit;

[0017] The analog-to-digital converter circuit is used to convert the phase data and the amplitude data into digital signals and send them to the processing unit.

[0018] In some optional embodiments, the optical signal modulation circuit includes a modulation signal generation sub-circuit, a signal equalization circuit, and a light source driving sub-circuit:

[0019] The modulation signal generation sub-circuit is used to generate the modulation signal;

[0020] The signal equalization circuit is used to divide the modulated signal into a first modulated sub-signal and a second modulated sub-signal, and input the first modulated sub-signal to the light source driving sub-circuit, and input the second modulated sub-signal as the reference signal to the electrical signal detection circuit;

[0021] The light source driving sub-circuit is used to drive multiple light source elements to generate the probe light according to the first modulation sub-signal.

[0022] In some optional embodiments, the electrical signal detection circuit includes a power comparison sub-circuit and a phase detection sub-circuit:

[0023] The power comparator sub-circuit is used to extract the amplitude data of the probe signal;

[0024] The phase detection sub-circuit is used to receive the second modulation sub-signal, perform phase difference detection on the second modulation sub-signal and the detection signal, and obtain the phase data.

[0025] In some optional embodiments, the optical signal modulation circuit further includes:

[0026] A modulation signal amplification sub-circuit is used to amplify the modulation signal and input the amplified modulation signal to the signal equalization circuit.

[0027] The signal equalization circuit is used to divide the amplified modulation signal into a first modulation sub-signal and a second modulation sub-signal, and input the first modulation sub-signal to the light source driving sub-circuit, and input the second modulation sub-signal as the reference signal to the electrical signal detection circuit.

[0028] In some optional embodiments, the optical signal detection circuit includes an optical signal receiving sub-circuit, an optical signal conversion sub-circuit, and a filtering sub-circuit:

[0029] The optical signal receiving sub-circuit is used to receive the optical signal after the probe light is reflected by the tissue being tested, and to input the optical signal to the optical signal conversion sub-circuit.

[0030] The optical signal conversion sub-circuit is used to convert the optical signal into an electrical signal and input the electrical signal to the filter sub-circuit;

[0031] The filter sub-circuit is used to filter the electrical signal to obtain the detection signal.

[0032] In some optional embodiments, the processing unit is further configured to adjust the detection parameters of the detection unit according to the control commands returned by the target master control unit, wherein the detection parameters include at least one of sampling rate and light source wavelength.

[0033] In some optional embodiments, it also includes:

[0034] A power management unit is provided for supplying power to the detection unit and the processing unit.

[0035] In some alternative embodiments, the detection unit, the processing unit, and the power management unit are respectively disposed on different circuit boards.

[0036] In some optional embodiments, the power management unit, the processing unit, and the detection unit are arranged layer by layer.

[0037] At least one embodiment of this application also provides a frequency-domain near-infrared spectroscopy device, including the frequency-domain near-infrared spectroscopy measurement module described above.

[0038] At least one embodiment of this application also provides a method for measuring frequency-domain near-infrared spectroscopy, applied to the aforementioned frequency-domain near-infrared spectroscopy measurement module, comprising:

[0039] A probe light is emitted toward the tissue being tested, and a probe signal is received after the probe light is reflected by the tissue being tested.

[0040] The amplitude and phase data of the detected signal are extracted, and the amplitude and phase data are then converted from analog to digital.

[0041] Based on the amplitude and phase data converted into digital signals, the optical parameters of the tested tissue are calculated.

[0042] The optical parameters are transmitted to the target main control unit wirelessly.

[0043] The frequency-domain near-infrared spectroscopy measurement module and frequency-domain near-infrared spectroscopy device provided in the embodiments of this application emit probe light to the tissue under test on the user's head through a detection unit, receive the detection signal formed after the probe light is reflected by the tissue under test, and extract the amplitude and phase data of the detection signal, thereby completing the preliminary processing of the analog data. Afterwards, the detection unit converts the amplitude and phase data obtained from the preliminary processing into analog-to-digital data and sends it to the processing unit. The processing unit preprocesses the amplitude and phase data to obtain the optical parameters of the tissue under test. This series of processing steps is all set up in the front-end measurement module, unlike the prior art, which requires sending a large number of analog signals obtained from the front-end measurement to a desktop network analyzer or computer. Therefore, the frequency-domain near-infrared spectroscopy measurement module of this application, unlike traditional FD-fNIRS devices that require the introduction of a high-speed ADC to transfer the signal to an FPGA or PC for digital processing, does not rely on FPGA or other digital systems for calculation. Phase and amplitude information are directly extracted at the acquisition front end, and after the DC output value is acquired by the ADC, the processing unit completes the preliminary preprocessing and sends the result to the main control unit. This system architecture brings at least the following benefits:

[0044] 1. Improve system portability and ease of operation

[0045] Signal transmission between the acquisition front-end (frequency domain measurement module) and the main control unit is via wireless communication (such as Bluetooth or WiFi), eliminating the need for excessive cable connections. Wireless connectivity not only reduces the bulk and weight burden caused by cables but also greatly improves the system's portability and operational flexibility, making it suitable for brain activity monitoring needs in dynamic scenarios.

[0046] 2. Reduce data transmission bandwidth requirements and optimize communication efficiency.

[0047] This allows communication between the acquisition front-end (frequency domain measurement module) and the system main controller to be achieved through low-bandwidth wireless transmission, avoiding the complex device connection problems encountered during high-bandwidth signal transmission. Furthermore, this improvement reduces system cost, size, and weight, while supporting the integration of more acquisition channels.

[0048] 3. Reduce reliance on mixers and simplify the design of the acquisition front-end (frequency domain measurement module).

[0049] By enabling the detection unit to directly extract the amplitude and phase data of the detected signal, the need for signal down-conversion using a mixer is reduced, thus eliminating the need for an additional precise frequency signal source and mixing device. This improvement not only simplifies the hardware design of the acquisition front-end but also reduces high-frequency signal interference, while enhancing system stability and reliability, and making multi-channel integration more convenient.

[0050] 4. Onboard integration of signal generation and detection functions.

[0051] This application integrates the generation of probe light, optical signal detection, and photoelectric signal receiving and distribution circuitry into a modular acquisition front end. Working in conjunction with onboard phase and amplitude detectors, it completes the generation and detection of optical signals. This design reduces reliance on external benchtop equipment (such as signal generators and network analyzers) and achieves modular integration of signal generation and detection. This significantly improves the overall system integration, laying the foundation for the practical application of wearable FD-fNIRS devices. Attached Figure Description

[0052] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, and these illustrative descriptions do not constitute a limitation on the embodiments.

[0053] Figure 1 This is a schematic diagram of the structure of a frequency-domain near-infrared spectroscopy measurement module provided in one embodiment of this application. Figure 1 ;

[0054] Figure 2 This is a schematic diagram of the internal structure of the detection unit in a frequency domain near-infrared spectroscopy measurement module provided in another embodiment of this application;

[0055] Figure 3 This is a schematic diagram illustrating the interaction between the processing unit and the target main control unit in a frequency domain near-infrared spectroscopy measurement module, provided in another embodiment of this application.

[0056] Figure 4 This is a schematic diagram of the structure of a frequency-domain near-infrared spectroscopy measurement module provided in another embodiment of this application. Figure 2 ;

[0057] Figure 5 This is a schematic diagram of the structure of a frequency-domain near-infrared spectroscopy measurement module provided in another embodiment of this application. Figure 3 ;

[0058] Figure 6 This is a schematic diagram of the optical signal acquisition and processing process of a frequency domain near-infrared spectroscopy device provided in another embodiment of this application. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this application to help readers better understand this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments. The division of the various embodiments below is for the convenience of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0060] To facilitate understanding of the embodiments of this application, relevant content regarding the FD-fNIRS device will be introduced first.

[0061] FD-fNIRS devices typically consist of the following units:

[0062] Signal generation unit: generates a modulated light source;

[0063] Light source modulation unit: modulates the light source to generate high-frequency modulated light;

[0064] Photodetector unit: detects reflected or transmitted light signals;

[0065] Signal analysis unit: processes and analyzes the amplitude and phase information of optical signals.

[0066] The existing FD-fNIRS system has the following main technical drawbacks:

[0067] 1) The system relies on desktop devices and lacks true wearability.

[0068] Most existing FD-fNIRS systems are built on desktop devices, requiring large external desktop equipment for core functional modules (such as signal modulation and signal analysis units). Although some designs attempt to make the light source and detection modules partially wearable, the overall system still cannot escape the dependence on desktop equipment. For example, the modulation light source signal is usually provided by a signal generator, and signal processing relies on network analyzers or computers. This design results in bulky equipment, restricts user movement in dynamic scenarios, and fails to meet practical application needs.

[0069] 2) Performance bottlenecks caused by the complexity of high-speed signal acquisition and processing

[0070] The core of the FD-fNIRS system lies in the acquisition and processing of amplitude and phase information of high-frequency optical signals. Existing technologies typically employ three methods, each with its own limitations:

[0071] 2.1 High-speed ADC direct signal acquisition: requires extremely high sampling rates (such as 200MSPS and above) and high-speed data transmission, resulting in complex hardware design, high power consumption, and difficulty in multi-channel expansion.

[0072] 2.2 Mixer down-frequency acquisition of signals: This adds an extra frequency source and mixing components, complicating the design. At the same time, interference between multiple channel signals is difficult to control, affecting system stability.

[0073] 2.3 Dedicated phase / amplitude measurement chip: Although it can reduce design complexity, existing chips are not yet mature, lack market verification, have insufficient reliability, and are costly.

[0074] 3) The overall miniaturization and integration of the system are insufficient.

[0075] Current FD-fNIRS system designs largely focus on miniaturization of specific modules (such as light sources and detector modules), but system-level integration improvements remain insufficient. Furthermore, most of these devices lack comprehensive testing in real-world scenarios, and their performance and stability in complex application environments have not been fully validated, limiting their clinical and commercial deployment.

[0076] 4) High cost

[0077] Existing FD-fNIRS systems typically use high-cost components such as high-speed ADCs and network analyzers, and rely on complex benchtop equipment, resulting in excessively high overall R&D and production costs. This high cost limits the large-scale application of the equipment in the medical and research fields.

[0078] To address the aforementioned technical issues of the bulky size of FD-fNIRS devices and the resulting limitations on user movement in dynamic scenarios, this invention proposes a frequency-domain near-infrared spectroscopy measurement module. The implementation details of this embodiment's frequency-domain near-infrared spectroscopy measurement module are described below. The following content is provided for ease of understanding and is not essential for implementing this solution.

[0079] Example 1:

[0080] like Figure 1 As shown, the frequency domain near-infrared spectroscopy measurement module of this embodiment includes: a detection unit 110 and a processing unit 120.

[0081] The detection unit 110 is used to make direct contact with the user's head, emit detection light to the tissue to be tested on the user's head, receive the detection signal formed after the detection light is reflected by the tissue to be tested, extract the amplitude data and phase data of the detection signal, and send the amplitude data and phase data to the processing unit 120 after analog-to-digital conversion.

[0082] The processing unit 120 is used to calculate the optical parameters of the tested tissue based on the amplitude data and phase data converted into digital signals, and to transmit the optical parameters to the target main control unit 130 via wireless transmission.

[0083] In this embodiment, the detection unit 110 integrates functions such as light source emission, optical signal reception, signal processing, and analog-to-digital conversion (ADC). Specifically, for the light source emission function, the light source for the detection light can be a near-infrared LED or a laser diode. For the optical signal reception function, the detection light emitted by the light source is guided to the user's head through an optical fiber, while the reflected optical signal is received. For example, a silicon photodiode or avalanche photodiode (APD) can be used to convert the received weak optical signal into an electrical signal, i.e., a detection signal. For the signal processing function, the detection unit can integrate preliminary signal conditioning circuitry, such as amplifiers and filters, to enhance signal strength and reduce noise interference. For frequency domain measurements, the detection unit 110 also integrates a phase detector and an amplitude detector or similar circuitry to extract the amplitude and phase data of the detection signal. To convert the continuously changing detection signal (i.e., analog signal) into a digital signal for subsequent digital signal processing by the processing unit 120, the detection unit 110 integrates an analog-to-digital converter (ADC).

[0084] Processing unit 120 receives digital signals from detection unit 110, which contain amplitude and phase data of the probe light. The data reception process can be performed via a serial communication interface (such as UART, SPI, I2C, etc.). Before calculating optical parameters, processing unit 120 preprocesses the received digital signals to eliminate noise, correct errors, or enhance the signal. Preprocessing steps may include filtering, DC offset removal, and normalization.

[0085] The processing unit 120 uses a preset optical model and algorithm to calculate the optical parameters of the tissue under test based on the received amplitude and phase data. The optical parameters may include light absorption coefficient, light scattering coefficient, and optical path length. Then, the processing unit 120 transmits the calculated optical parameters to the target master control unit 130 via wireless transmission (such as Bluetooth, Wi-Fi, Zigbee, etc.).

[0086] The target control unit 130 is a device responsible for receiving, processing, and further analyzing or storing the optical parameters sent by the processing unit 120. The specific form and carrier of the target control unit 130 can vary depending on the application scenario. For example, it can be a portable medical testing device, such as a handheld or wearable device, a smartphone, tablet, or a dedicated medical monitor; it can also be a computer workstation fixed in a medical clinic or research institution; or a data center server located in the cloud. The target control unit 130 has data processing capabilities, which can convert optical parameters into more easily understood medical indicators (such as blood oxygen saturation, tissue oxygen content, etc.) and display them on a screen in the form of reports or charts for medical personnel or users to view.

[0087] Wireless transmission offers flexibility and convenience, freeing measurement systems from the constraints of wired connections. This improves upon the limitations imposed on user movement in dynamic scenarios by existing technologies, making the measurement systems portable and suitable for use in medical settings, homes, or outdoor environments.

[0088] In summary, the frequency-domain near-infrared spectroscopy measurement module and frequency-domain near-infrared spectroscopy device provided in this embodiment emit probe light to the tissue under test on the user's head through a detection unit, receive the detection signal formed after the probe light is reflected by the tissue under test, and extract the amplitude and phase data of the detection signal, thereby completing the preliminary processing of the analog data. Afterwards, the detection unit converts the amplitude and phase data obtained from the preliminary processing into analog-to-digital data and sends it to the processing unit. The processing unit preprocesses the amplitude and phase data to obtain the optical parameters of the tissue under test. This series of processing steps is all performed in the front-end measurement module, unlike existing technologies that require sending a large number of analog signals obtained from the front-end measurement to a desktop network analyzer or computer. Therefore, the frequency-domain near-infrared spectroscopy measurement module of this application, unlike traditional FD-fNIRS devices that require the introduction of a high-speed ADC to transfer the signal to an FPGA for digital processing, does not rely on FPGAs or other digital systems for calculations. Phase and amplitude information are directly extracted at the acquisition front end, and after the DC output value is acquired by the ADC, the processing unit completes the preliminary preprocessing and sends the results to the main control unit.

[0089] This system architecture brings at least the following benefits:

[0090] 1. Improve system portability and ease of operation

[0091] Signal transmission between the acquisition front-end (frequency domain measurement module) and the main control unit is via wireless communication (such as Bluetooth or WiFi), eliminating the need for excessive cable connections. Wireless connectivity not only reduces the bulk and weight burden caused by cables but also greatly improves the system's portability and operational flexibility, making it suitable for brain activity monitoring needs in dynamic scenarios.

[0092] 2. Reduce data transmission bandwidth requirements and optimize communication efficiency.

[0093] This allows communication between the acquisition front-end (frequency domain measurement module) and the system main controller to be achieved through low-bandwidth wireless transmission, avoiding the complex device connection problems encountered during high-bandwidth signal transmission. Furthermore, this improvement reduces system cost, size, and weight, while supporting the integration of more acquisition channels.

[0094] 3. Reduce reliance on mixers and simplify the design of the acquisition front-end (frequency domain measurement module).

[0095] By enabling the detection unit to directly extract the amplitude and phase data of the detected signal, the need for signal down-conversion using a mixer is reduced, thus eliminating the need for an additional precise frequency signal source and mixing device. This improvement not only simplifies the hardware design of the acquisition front-end but also reduces high-frequency signal interference, while improving the stability and reliability of the system and making multi-channel integration more convenient.

[0096] 4. Onboard integration of signal generation and detection functions.

[0097] This application integrates the generation of probe light, optical signal detection, and photoelectric signal receiving and distribution circuitry into a modular acquisition front end. Working in conjunction with onboard phase and amplitude detectors, it completes the generation and detection of optical signals. This design reduces reliance on external benchtop equipment (such as signal generators and network analyzers) and achieves modular integration of signal generation and detection. This significantly improves the overall system integration, laying the foundation for the practical application of wearable FD-fNIRS devices.

[0098] like Figure 2As shown, in some optional embodiments, the detection unit 110 includes an optical signal modulation circuit 111, an optical signal detection circuit 112, an electrical signal detection circuit 113, and an analog-to-digital converter circuit 114: the optical signal modulation circuit 111 is used to generate a modulation signal, which is used to drive the light source to generate the detection light and is input as a reference signal to the electrical signal detection circuit 113; the optical signal detection circuit 112 is used to receive the detection signal and send the detection signal to the electrical signal detection circuit 113; the electrical signal detection circuit 113 is used to extract the phase data and amplitude data of the detection signal based on the reference signal and send the amplitude data and phase data to the analog-to-digital converter circuit 114; the analog-to-digital converter circuit 114 is used to convert the phase data and amplitude data into digital signals and send them to the processing unit 120.

[0099] In this embodiment, the detection unit 110 integrates multiple key circuit modules that work together to achieve efficient and accurate optical signal detection and data processing. Each circuit module is described in detail below:

[0100] Optical signal modulation circuit 111: Responsible for generating a modulation signal, which is used not only to drive the light source (such as a laser) to generate probe light, but also as a reference signal in the subsequent electrical signal detection process. The modulation signal typically has a specific frequency, phase, and waveform to ensure that the characteristics of the probe light meet the measurement requirements. Modulation can significantly improve the signal-to-noise ratio of the probe signal and enhance the system's anti-interference capability. Simultaneously, using a known modulation signal as a reference helps to accurately extract the phase and amplitude information of the probe signal in subsequent steps.

[0101] The optical signal detection circuit 112 is responsible for receiving the detection signal (i.e., optical signal) reflected or transmitted back from the object being measured and converting it into an electrical signal. As the front end of the detection system, the performance of the optical signal detection circuit 112 directly affects the sensitivity, response speed, and measurement accuracy of the entire system. An efficient detection circuit can capture weak optical signals, laying the foundation for subsequent accurate measurements.

[0102] Electrical signal detection circuit 113: This circuit compares and processes a reference signal (from the optical signal modulation circuit) with a detection signal (from the electrical signal converted by the optical signal detection circuit) to extract the phase and amplitude data of the detection signal. This circuit can be implemented using circuits such as a phase-locked loop (PLL) and an amplitude detector.

[0103] Analog-to-digital converter (ADC) 114: Responsible for converting the phase data and amplitude data (usually analog signals) output by the electrical signal detection circuit into digital signals so that the subsequent digital signal processing unit 120 (such as a microprocessor, ESP32 microcontroller, etc.) can process and analyze them, providing a reliable foundation for subsequent algorithm processing.

[0104] In some alternative embodiments, the ADC used during signal acquisition can be replaced with different models, such as 12-bit or 16-bit resolution ADCs, depending on the sampling rate and resolution requirements, to adapt to different accuracy and bandwidth requirements. No specific limitations are imposed here.

[0105] In summary, the detection unit 110 in this embodiment, through the aforementioned circuit module chain, realizes a complete process from the generation and detection of optical signals to the extraction, conversion, and digital processing of electrical signals. This eliminates the reliance on external desktop devices (such as signal generators and network analyzers) and achieves modular integration of signal generation and detection. This significantly improves the overall integration of the system, laying the foundation for the practical application of wearable FD-fNIRS devices and providing a rich information basis for subsequent data processing and decision-making.

[0106] In some optional embodiments, the optical signal modulation circuit includes a modulation signal generation sub-circuit, a signal equalization circuit, and a light source driving sub-circuit: the modulation signal generation sub-circuit is used to generate the modulation signal; the signal equalization circuit is used to divide the modulation signal into a first modulation sub-signal and a second modulation sub-signal, and input the first modulation sub-signal to the light source driving sub-circuit, and input the second modulation signal as the reference signal to the electrical signal detection circuit; the light source driving sub-circuit is used to drive multiple light sources according to the first modulation signal to generate the probe light.

[0107] In this embodiment, the modulation signal generation sub-circuit can generate a high-frequency modulation signal (50-100MHz) under the control of a microprocessor using an onboard VCO (Voltage Controlled Oscillator). The signal equalization circuit includes a signal equalizer and an RF switch, and the light source driving sub-circuit can be an LD driver device, correspondingly, the light source device is a laser diode (LD). The modulation signal is sent to the signal equalizer. One path is distributed to the LD driver device via the RF switch to modulate multiple laser diodes (LDs) to generate modulated light (i.e., probe light); the other path serves as a reference signal input to the electrical signal detection circuit.

[0108] In some alternative embodiments, the light source can also be a wavelength-tunable laser diode (LD), or an LED light source can be used in low-precision scenarios to adapt to different precision and application requirements.

[0109] In some alternative embodiments, the LD driver (or light source driver sub-circuit) may be selected from other models with higher efficiency or supporting a wider modulation frequency range, such as driver chips with lower noise and dynamic control capabilities, to further optimize the stability of the light source.

[0110] In some optional embodiments, the electrical signal detection circuit includes a power comparison sub-circuit and a phase detection sub-circuit: the power comparison sub-circuit is used to extract the amplitude data of the probe signal; the phase detection sub-circuit is used to receive the second modulation sub-signal, perform phase difference detection on the second modulation sub-signal and the probe signal, and obtain the phase data.

[0111] In this embodiment, the power comparison sub-circuit can be an amplitude detector, and the phase detection sub-circuit can be a phase detector. The probe signal enters the amplitude detector and the phase detector through an equalizer; the amplitude detector extracts the amplitude value of the signal and acquires the data through the analog-to-digital converter (ADC) circuit described above; the phase detector detects the phase difference between the optical signal and the reference signal, and after filtering, acquires the data through the analog-to-digital converter (ADC) circuit described above as well.

[0112] Both the amplitude detector and the phase detector are commercially available, mature components, avoiding the use of small-batch custom components with strong experimental requirements. This choice not only reduces the development and production costs of multi-channel and multi-acquisition front-end systems but also improves the quality and stability of the devices and systems. The widespread availability of commercially available components also facilitates the mass production and promotion of the system, making the product of this application significantly practical.

[0113] In some alternative embodiments, the phase detector (or phase detection subcircuit) may be a discrete digital phase detector or an integrated phase detection module in a phase-locked loop (PLL) to further improve the accuracy of signal phase difference measurement.

[0114] In some alternative embodiments, the amplitude detector (or power comparator subcircuit) may be selected as a logarithmic signal power detector (for signals with a large dynamic range) or an envelope detector (suitable for signals with low bandwidth requirements) to ensure accurate extraction of amplitude information.

[0115] In some alternative embodiments, the separate phase detection subcircuit and power comparison subcircuit can also be replaced by an integrated chip such as the AD8302 that integrates phase and amplitude detection functions. Such integrated chips can further simplify circuit design, reduce the number of components, and are suitable for devices with limited size.

[0116] In some optional embodiments, the optical signal modulation circuit further includes: a modulation signal amplification sub-circuit for amplifying the modulation signal and inputting the amplified modulation signal to the signal equalization circuit; the signal equalization circuit for dividing the amplified modulation signal into a first modulation sub-signal and a second modulation sub-signal, inputting the first modulation sub-signal to the light source driving sub-circuit, and inputting the second modulation sub-signal as the reference signal to the electrical signal detection circuit.

[0117] In this embodiment, the modulation signal amplification subcircuit is used to amplify the modulation signal. The modulation signal is typically a low-frequency or mid-frequency analog signal carrying information to be modulated onto the optical signal. However, the amplitude of the original modulation signal may be insufficient to drive subsequent circuits (such as the light source driver subcircuit and the signal equalization circuit) to achieve the required performance. Therefore, the original modulation signal needs to be amplified by the modulation signal amplification subcircuit to ensure that subsequent processing can be performed accurately and stably.

[0118] In some optional embodiments, the optical signal detection circuit includes an optical signal receiving sub-circuit, an optical signal conversion sub-circuit, and a filtering sub-circuit: the optical signal receiving sub-circuit is used to receive the optical signal reflected by the probe light through the tissue under test, and input the optical signal to the optical signal conversion sub-circuit; the optical signal conversion sub-circuit is used to convert the optical signal into an electrical signal, and input the electrical signal to the filtering sub-circuit; the filtering sub-circuit is used to filter the electrical signal to obtain the probe signal.

[0119] In this embodiment, the optical signal receiving sub-circuit can be implemented based on a high-speed silicon photodiode (SiPD), and the optical signal conversion sub-circuit can be implemented using a transimpedance amplifier (TIA). The optical signal transmitted / reflected by the tissue under test is detected by the high-speed silicon photodiode (SiPD), converted into an electrical signal by the transimpedance amplifier (TIA), and then filtered to become the detection signal.

[0120] like Figure 2 and Figure 3 As shown, in some optional embodiments, the processing unit 120 is further configured to adjust the detection parameters of the detection unit 110 according to the control commands returned by the target main control unit 130, wherein the detection parameters include at least one of sampling rate and light source wavelength.

[0121] Specifically, the processing unit in this embodiment uses an ESP32 microcontroller as its core to complete signal acquisition, preprocessing, and wireless transmission. Its functions include: receiving amplitude and phase data from the ADC and calculating the optical parameters of the tissue under test; transmitting the optical parameters to the system's main control unit via a wireless module (Bluetooth or WiFi); and performing logical and timing control on parameters such as the sampling rate and light source wavelength of the underlying modules according to instructions from the main control unit, greatly improving the flexibility and user experience of the head-mounted measurement device.

[0122] Sampling rate refers to the number of times the detection unit collects data per second. By default, frequency-domain near-infrared spectroscopy devices may have a standard sampling rate set to balance data accuracy and processing speed. However, in certain specific situations, it may be desirable to adjust the sampling rate to meet different needs. For example, monitoring the brain activity of a user undergoing exercise rehabilitation training requires observing the user's brain responses during specific motor tasks. This necessitates a higher sampling rate to capture rapidly changing signals, ensuring that subtle changes in brain activity are captured. By issuing an adjustment command to adjust the sampling rate from the target control unit, the processing unit executes the command, increasing the sampling rate of the detection unit. The detection unit will then collect data more frequently, providing more intensive information on physiological state changes, helping to accurately understand the user's brain recovery status. Conversely, if the user is at rest and real-time data requirements are not high, but reducing device power consumption and data processing burden is desired, the sampling rate can be reduced.

[0123] The near-infrared spectroscopy frequency domain measurement module in this embodiment uses light sources of different wavelengths to probe brain tissue. Different wavelengths of light have different absorption and scattering characteristics when penetrating tissue, thus reflecting different physiological information within the tissue. In some cases, it is necessary to adjust the wavelength of the light source to obtain more specific physiological parameters. For example, some wavelengths of light may be more sensitive to changes in blood oxygen levels, while other wavelengths may be more sensitive to changes in blood flow velocity or vascular structure. The target control unit adjusts the wavelength of the light source and sends adjustment commands to the processing unit to adjust the wavelength of the light source used by the detection unit. In this way, the frequency domain near-infrared spectroscopy device can flexibly switch the wavelength of the light source according to different measurement needs, thereby providing more accurate and comprehensive physiological state information.

[0124] In summary, the processing unit adjusts the detection parameters (such as sampling rate and light source wavelength) of the detection unit according to the control instructions returned by the target main control unit, which improves the flexibility of the device and the user experience, enabling users to understand their physiological state more accurately and take corresponding measures.

[0125] In some alternative embodiments, the processing unit can also be other processing units with similar functions to the ESP32 microcontroller, such as the STM32 series microcontrollers or Raspberry Pi. These processing units all have signal acquisition, preprocessing, and wireless communication functions, while also meeting the requirements for data processing and instruction logic control. Embedded systems such as Raspberry Pi can also be expanded with additional functional modules to adapt to different application scenarios.

[0126] like Figure 4 As shown, in some optional embodiments, it further includes a power management unit 140, which is used to supply power to the detection unit 110 and the processing unit 120.

[0127] In this embodiment, the power management unit 140 works closely in coordination with the detection unit 110 and the processing unit 120. The detection unit 110 and the processing unit 120 may require different power supplies when performing tasks, and the power management unit 140 dynamically adjusts these supplies according to their needs. Simultaneously, the power management unit 140 also needs to monitor the power consumption of the detection unit 110 and the processing unit 120 to ensure that they always operate within a safe power range.

[0128] Specifically, the power management unit 140 may employ an integrated power management chip to support the independent power supply requirements of the detection unit 110 and the processing unit 120. The power management unit 140 ensures structural stability and signal integrity with the detection unit 110 and the processing unit 120 through standardized mechanical connections.

[0129] In some alternative embodiments, the power management unit 140 can be replaced with other types of chips, such as a linear regulator (suitable for low-power devices) or a DC-DC converter (suitable for high-efficiency power supply scenarios), depending on the power consumption requirements of different circuit boards, to ensure the stability and efficiency of power supply.

[0130] like Figure 5 As shown, in some optional embodiments, the detection unit 110, the processing unit 120 and the power management unit 140 are respectively disposed on different circuit boards.

[0131] In this embodiment, by placing each unit on a different circuit board, the frequency domain near-infrared spectroscopy measurement module achieves a modular design. This design makes each part relatively independent. If a unit fails or needs to be upgraded, only the corresponding circuit board needs to be replaced or upgraded, without disassembling or overhauling the entire device. This greatly reduces maintenance and upgrade costs and improves the maintainability of the equipment.

[0132] On the other hand, by separating the circuit boards with different functions, direct interference between digital and analog circuits can be effectively avoided. Separate layout can reduce electromagnetic coupling between circuit boards, thereby reducing the generation and propagation of interference signals. For example, placing digital and analog circuit boards on different layers can reduce capacitive and inductive coupling between them, making it less likely for noise generated by digital circuits to indirectly interfere with analog circuits through common ground lines or power lines. This protects the purity of analog signals and helps to improve the accuracy and stability of the signals received by the detection unit 110, thus improving the precision and reliability of measurements.

[0133] In some alternative embodiments, different frequency-domain near-infrared spectroscopy measurement modules interact to generate new detection channels for receiving different detection signals.

[0134] In this embodiment, the light source components and optical signal detection circuits among multiple measurement modules mutually constitute new detection channels. This results in an exponential increase in the number of detection channels generated by the frequency-domain near-infrared spectroscopy device with each additional measurement module added. A greater number of channels allows the system to capture more detection signals, leading to higher imaging spatial resolution and consequently, higher imaging quality.

[0135] like Figure 5 As shown, in some optional embodiments, the power management unit 140, the processing unit 120 and the detection unit 110 are arranged layer by layer.

[0136] In this embodiment, the layered layout design enables more efficient use of the internal space of the head-mounted device. By stacking circuit boards with different functions together, the area occupied by each frequency domain near-infrared spectroscopy measurement module can be significantly reduced, making the layout of the measurement modules for each frequency domain near-infrared spectroscopy more compact. Consequently, the frequency domain near-infrared spectroscopy device can accommodate more measurement modules within a fixed area, which is beneficial for improving imaging spatial resolution.

[0137] At the same time, by laying them out layer by layer, a certain gap is created between each circuit board, allowing air to circulate more easily and thus improving the heat dissipation performance of the equipment.

[0138] In an optional embodiment, the layout and heat dissipation measures among the power management unit 140, the processing unit 120, and the detection unit 110 are adjusted according to the heat generation of each unit to further improve heat dissipation efficiency. For example, the processing unit 120 is placed in the first layer (the side closer to the tissue being tested is the first layer), the detection unit 110 is placed in the second layer, and the power management unit 140 is placed in the third layer; or, the detection unit 110 is placed in the first layer, the processing unit 120 is placed in the second layer, and the power management unit 140 is placed in the third layer to optimize the integration and operational stability of the modules.

[0139] Based on the above embodiments, the frequency domain near-infrared spectroscopy measurement module of this embodiment has significant improvements in at least the following four aspects:

[0140] 1. Direct processing and extraction of high-frequency photoelectric signals

[0141] Commercially available dedicated phase and amplitude detectors are used to directly process high-frequency (50–100 MHz) photoelectric signals, extracting phase and amplitude difference information. This method avoids the complex process of calculating phase / amplitude differences in FPGAs or PCs using digital computation methods such as the Özil algorithm in traditional systems, and also eliminates the need for frequency down-conversion processing of high-frequency signals, simplifying system design and significantly reducing hardware costs and power consumption.

[0142] 2. Front-end signal preprocessing and wireless transmission

[0143] At the acquisition front end, a microcontroller preprocesses the phase difference and amplitude difference information acquired by the detection chip to directly calculate the optical parameters of the measured tissue (such as blood oxygen concentration). The preprocessed results are then transmitted wirelessly (such as via Bluetooth or WiFi) to the system main controller based on an FPGA or PC. This architecture reduces the signal transmission bandwidth requirements while improving the overall system efficiency and modularity.

[0144] 3. Onboard integrated optical signal generation and detection functions

[0145] Based on the onboard modulated light source, photodetector circuit, and modulated signal generation / photoelectric signal distribution circuit, the frequency domain near-infrared spectroscopy measurement module of this application can independently complete the generation, reception, and processing of optical signals without the need for external signal generation or detection equipment. This technology achieves complete independence of the acquisition module, significantly improves the portability and integration of the system, and lays the foundation for the realization of a modular wearable FD-fNIRS system.

[0146] 4. Reduce development and production costs and improve system reliability.

[0147] The components used in this embodiment are all commercially available and mature components, avoiding the use of small-batch custom components with a strong experimental nature. This choice not only reduces the development and production costs of multi-channel and multi-acquisition front-end systems, but also improves the quality and stability of the components and the system. The widespread availability of commercial components also facilitates the mass production and promotion of the system.

[0148] Example 2:

[0149] Based on the above embodiments, this embodiment provides a frequency-domain near-infrared spectroscopy device. For example... Figure 6 The diagram shown illustrates the optical signal acquisition and processing flow of a frequency-domain near-infrared spectroscopy device. The frequency-domain near-infrared spectroscopy device utilizes the aforementioned frequency-domain near-infrared spectroscopy measurement module (i.e.... Figure 6 The acquisition front-end modules (1 to N) enable the frequency domain near-infrared spectroscopy equipment to be miniaturized, have low power consumption and high integration, and improve the situation where users' activities are restricted in dynamic scenes.

[0150] For example, in one application scenario, there is a need to study / monitor brain activity and brain health, such as monitoring the brain activity of a user undergoing exercise rehabilitation training, to better understand and evaluate the user's rehabilitation outcomes. This frequency-domain near-infrared spectroscopy device is head-mounted, worn by the user. The main components of the device are: a detection unit, which makes close and secure contact with the user's head, particularly for the tissue areas that need to be measured, such as the frontal region of the brain.

[0151] When a user puts on the frequency-domain near-infrared spectroscopy device and activates it, the detection unit begins to work, emitting near-infrared detection light towards the tissue being measured on the user's head. This light can penetrate the scalp and interact with brain tissue. Subsequently, some of the detection light is reflected back by the tissue, forming a detection signal carrying information about the internal structure of the tissue. The detection unit not only receives these reflected light signals but is also responsible for extracting crucial amplitude and phase data from them, which form the basis for subsequent analysis.

[0152] Once this critical data is detected, the detection unit immediately performs analog-to-digital conversion, transforming the analog signal into a digital signal to ensure the accuracy and stability of the data. The converted data is then rapidly sent to the processing unit.

[0153] Upon receiving this data, the processing unit immediately begins calculating the optical parameters of the tested tissue. These optical parameters are crucial for understanding the physiological state of brain tissue, such as blood oxygen levels and blood flow velocity. After calculation, the processing unit does not directly display the data to the user. Instead, it transmits the data via a built-in wireless transmission module to the target control unit integrated into a tablet or monitor used by medical personnel. The target control unit then displays this data in intuitive charts or numerical values ​​to better illustrate the changes in the physiological state of the tested user's brain.

[0154] In one application scenario, the main control unit is needed to adjust detection parameters, such as the sampling rate and the wavelength of the light source, in order to more accurately understand and evaluate the rehabilitation results of the tested user.

[0155] By default, a device may be set to a standard sampling rate to balance data accuracy and processing speed. However, in certain specific situations, the sampling rate needs to be adjusted to meet different requirements. For example, observing a user's brain responses while performing a specific motor task requires a higher sampling rate to capture rapidly changing signals.

[0156] Specifically, the sampling rate is set to a high value (e.g., tens of times per second or more) on the tablet or monitor to ensure that subtle changes in brain activity can be captured. This allows the detection unit to collect data more frequently, providing more intensive information on changes in physiological state and helping to accurately understand the brain recovery status of the tested user.

[0157] The frequency-domain near-infrared spectroscopy device in this embodiment uses light sources of different wavelengths to detect brain tissue. Different wavelengths of light have different absorption and scattering characteristics when penetrating tissue, thus reflecting different physiological information within the tissue. In some cases, it is necessary to adjust the wavelength of the light source to obtain more specific physiological parameters. For example, some wavelengths of light may be more sensitive to changes in blood oxygen levels, while other wavelengths may be more sensitive to changes in blood flow velocity or vascular structure. The target control unit adjusts the wavelength of the light source and sends adjustment commands to the processing unit to adjust the wavelength of the light source used by the detection unit. In this way, the device can flexibly switch the wavelength of the light source according to different measurement needs, thereby providing more accurate and comprehensive physiological state information.

[0158] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing this application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of this application.

Claims

1. A frequency-domain near-infrared spectroscopy measurement module, characterized in that, Includes a detection unit and a processing unit. The detection unit is used to make direct contact with the user's head, emit detection light to the tissue to be tested on the user's head, receive the detection signal formed after the detection light is reflected by the tissue to be tested, extract the amplitude data and phase data of the detection signal, and send the amplitude data and phase data to the processing unit after analog-to-digital conversion. The processing unit is used to calculate the optical parameters of the tested tissue based on the amplitude data and phase data converted into digital signals, and to transmit the optical parameters to the target main control unit wirelessly.

2. The frequency domain near-infrared spectroscopy measurement module according to claim 1, characterized in that, The detection unit includes an optical signal modulation circuit, an optical signal detection circuit, an electrical signal detection circuit, and an analog-to-digital conversion circuit. The optical signal modulation circuit is used to generate a modulation signal, which is used to drive the light source to generate the detection light and is also used as a reference signal input to the electrical signal detection circuit. The optical signal detection circuit is used to receive the detection signal and send the detection signal to the electrical signal detection circuit; The electrical signal detection circuit is used to extract the phase data and amplitude data of the probe signal based on the reference signal, and send the amplitude data and phase data to the analog-to-digital conversion circuit; The analog-to-digital converter circuit is used to convert the phase data and the amplitude data into digital signals and send them to the processing unit.

3. The frequency domain near-infrared spectroscopy measurement module according to claim 2, characterized in that, The optical signal modulation circuit includes a modulation signal generation sub-circuit, a signal equalization circuit, and a light source driving sub-circuit. The modulation signal generation sub-circuit is used to generate the modulation signal; The signal equalization circuit is used to divide the modulated signal into a first modulated sub-signal and a second modulated sub-signal, and input the first modulated sub-signal to the light source driving sub-circuit, and input the second modulated sub-signal as the reference signal to the electrical signal detection circuit; The light source driving sub-circuit is used to drive multiple light source elements to generate the probe light according to the first modulation sub-signal.

4. The frequency domain near-infrared spectroscopy measurement module according to claim 3, characterized in that, The electrical signal detection circuit includes a power comparison sub-circuit and a phase detection sub-circuit: The power comparator sub-circuit is used to extract the amplitude data of the probe signal; The phase detection sub-circuit is used to receive the second modulation sub-signal, perform phase difference detection on the second modulation sub-signal and the detection signal, and obtain the phase data.

5. The frequency domain near-infrared spectroscopy measurement module according to claim 3, characterized in that, The optical signal modulation circuit further includes: A modulation signal amplification sub-circuit is used to amplify the modulation signal and input the amplified modulation signal to the signal equalization circuit. The signal equalization circuit is used to divide the amplified modulation signal into a first modulation sub-signal and a second modulation sub-signal, and input the first modulation sub-signal to the light source driving sub-circuit, and input the second modulation sub-signal as the reference signal to the electrical signal detection circuit.

6. The frequency domain near-infrared spectroscopy measurement module according to claim 2, characterized in that, The optical signal detection circuit includes an optical signal receiving sub-circuit, an optical signal conversion sub-circuit, and a filtering sub-circuit. The optical signal receiving sub-circuit is used to receive the optical signal after the probe light is reflected by the tissue being tested, and to input the optical signal to the optical signal conversion sub-circuit. The optical signal conversion sub-circuit is used to convert the optical signal into an electrical signal and input the electrical signal to the filter sub-circuit; The filter sub-circuit is used to filter the electrical signal to obtain the detection signal.

7. The frequency domain near-infrared spectroscopy measurement module according to claim 1, characterized in that, The processing unit is further configured to adjust the detection parameters of the detection unit according to the control commands returned by the target master control unit, wherein the detection parameters include at least one of sampling rate and light source wavelength.

8. The frequency domain near-infrared spectroscopy measurement module according to claim 1, characterized in that, Different frequency-domain near-infrared spectroscopy measurement modules interact to generate new detection channels, which are used to receive different detection signals.

9. The frequency domain near-infrared spectroscopy measurement module according to any one of claims 1-8, characterized in that, Also includes: A power management unit is provided for supplying power to the detection unit and the processing unit.

10. The frequency-domain near-infrared spectroscopy measurement module according to claim 9, characterized in that, The detection unit, the processing unit, and the power management unit are each mounted on a different circuit board.

11. The frequency domain near-infrared spectroscopy measurement module according to claim 10, characterized in that, The power management unit, the processing unit, and the detection unit are deployed layer by layer.

12. A frequency-domain near-infrared spectroscopy device, characterized in that, The measurement module for frequency-domain near-infrared spectroscopy as described in any one of claims 1-11.

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