Method and device for estimating average photon path of diffused light transmitted in biological tissue, medium and product

Abstract

The invention discloses an average photon path estimation method and device for transmission of diffused light in biological tissue, a medium and a product, and relates to the technical field of biological tissue blood oxygen imaging, the method comprises the following steps: obtaining transmission path lengths of a plurality of photon packets and corresponding detection intensities; selecting two serial numbers from the serial numbers of the photon packets to determine a path interval; the path interval comprises all photon packets between the two selected serial numbers; calculating the slope of the path interval according to the detection intensity and the transmission path length of each photon packet in the path interval; taking the slope as an estimated value of a tissue absorption coefficient; calculating the emission intensity of each photon packet according to the estimated value of the tissue absorption coefficient, the transmission path length of each photon packet and the corresponding detection intensity; and calculating an average photon path according to the emission intensity, the detection intensity and the estimated value of the tissue absorption coefficient of all photon packets. The average photon path can be accurately estimated.

Description

Technical Field

[0001] This application relates to the field of biological tissue blood oxygenation imaging technology, and in particular to a method, device, medium and product for estimating the average photon path of diffuse light propagating in biological tissue. Background Technology

[0002] Blood oxygenation in biological tissues is an important physiological parameter; the oxygenation level of tissues such as skeletal muscle, brain, and breast tissue is closely related to their health. For example, physical exercise, performing tasks, or external stimuli dilate capillary networks and accelerate blood circulation, resulting in a richer supply of oxygen and thus increasing tissue hemoglobin concentration and oxygen saturation. In pathological conditions such as muscle atrophy or vascular obstruction, the capillary network cannot be effectively activated, leading to decreased blood oxygenation levels or even hypoxia. Therefore, changes in tissue blood oxygenation concentration under physical exercise, task performance, or external stimuli are closely related to physiological state and constitute a functional technique for detecting various diseases.

[0003] Near-infrared diffuse optical spectroscopy (NIR spectroscopy) is a technique for detecting blood oxygenation in biological tissues. The principle involves placing several light sources and detectors on the surface of the tissue being measured, forming a light source-detector (SD) combination. The light sources sequentially emit a large number of photons into the tissue. After several scattering or absorption events within the tissue, some photons return to the tissue surface and are collected by the detector, thus acquiring the photon signal. In signal processing, the change in the absorption coefficient (Δμa) within the tissue is first estimated by measuring the change in light intensity collected by the detector. Since the main absorbers in biological tissues are oxy-hemoglobin, deoxy-hemoglobin, and water, the concentrations of oxy-hemoglobin ([ΔHbO2]) and deoxy-hemoglobin ([ΔHb]) can be calculated using the changes in the absorption coefficients at two or more wavelengths.

[0004] The physical principle behind blood oxygen measurement is mainly a modified Beer-Lambert (MBL) law, that is, at a specific wavelength ( λ The change in tissue absorption coefficient obtained under diffused light irradiation, given a light source-detector combination (light-detector combination). Δμ a ( λThe change in optical density divided by the average path length of a photon is expressed mathematically as follows: Δμ a ( λ )= ΔOD ( λ ) / MPL ( λ (); Here the optical density changes ΔOD ( λ ) for a specific time ( t The logarithmic change in detection intensity relative to the baseline time, i.e. ΔOD ( λ )=ln( I dB ( λ ) / I dt ( λ ));here I dB and I dt Baseline time and t The detection intensity at a given moment is the sum of the detection energies of all photon packets. MPL This is the average photon path length among the different photon path lengths of the photodetector combination, i.e., the average photon path.

[0005] However, traditional photon average path estimation methods either overestimate or underestimate the actual value, which will introduce errors into blood oxygen measurement. Summary of the Invention

[0006] The purpose of this application is to provide a method, device, medium, and product for estimating the average photon path of diffuse light propagating within biological tissues, which can accurately estimate the average photon path.

[0007] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a method for estimating the average photon path of diffuse light propagating within biological tissues, including: Acquire experimental data of the tested tissue under optical detection combination; the experimental data includes the transmission path length of several photon packets and the corresponding detection intensity; Two numbers are selected from the sequence numbers of the photon packets to determine a path interval; the path interval includes all photon packets between the two selected sequence numbers. The slope of the path interval is calculated based on the detection intensity of each photon packet within the path interval and the transmission path length. The slope is used as an estimate of the tissue absorption coefficient; The emission intensity of each photon packet is calculated based on the estimated value of the tissue absorption coefficient, the transmission path length of each photon packet, and the corresponding detection intensity. The average photon path is calculated based on the emission intensity, detection intensity, and estimated tissue absorption coefficient of all photon packets.

[0008] Optionally, the selection of the two sequence numbers satisfies: 1 ≤ k 1< k 2 ≤ n; where n is the total number of photon packets. k 1 and k 2 represents the selected sequence number; the path interval includes sequence number... k 1 to k All photon packets between 2.

[0009] Optionally, the slope of the path interval is calculated using the formula based on the detection intensity of each photon packet within the path interval and the transmission path length: ; in, Sl ( k 1, k 2) Represents the slope of the path interval; k 1 and k 2 represents the selected sequence number; I d ( i ) is the first i The detection intensity of each photon packet; L i For the first i The transmission path length of a photon packet; I d ( i+ 1) is the first i+ The detection intensity of a single photon packet; L i+1 For the first i+ The transmission path length of one photon packet.

[0010] Optionally, based on the estimated value of the tissue absorption coefficient, the transmission path length of each photon packet, and the corresponding detection intensity, the formula for calculating the emission intensity of each photon packet is as follows: ; in, I s ( i ) is the first i The emission intensity of a photon packet; I d ( i ) is the first i The detection intensity of each photon packet; μ a This is an estimate of the tissue absorption coefficient; L i For the first iThe transmission path length of a photon packet; Sl ( k 1, k 2) Represents the slope of the path interval.

[0011] Optionally, the formula for calculating the average photon path based on the emission intensity, detection intensity, and estimated value of the tissue absorption coefficient of all photon packets is as follows: ; in, L mean,3 This represents the average photon path; n is the total number of photon packets. I s ( i ) is the first i The emission intensity of a photon packet; I d ( i ) is the first i The detection intensity of each photon packet; μ a This is an estimated value for the tissue absorption coefficient.

[0012] Optionally, the experimental data consists of all photon packets and their corresponding information obtained through optical measurement or computer simulation; the photon packet information includes the photon energy and transmission path length of the photon packet; the photon packet is a combination of photons with the same path; the computer simulation is obtained by using Monte Carlo simulation to acquire the photon energy and transmission path length of several photon packets within a specified optical detector assembly; the optical detector assembly includes a light source and a detector; the optical detector assembly is disposed on the tissue under test.

[0013] Optionally, the tissue being tested may be the subject's skeletal muscle, brain, or breast tissue.

[0014] In a second aspect, this application provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the average photon path estimation method for diffuse light transmission within biological tissue as described above.

[0015] Thirdly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the average photon path estimation method for diffuse light propagation within biological tissue as described above.

[0016] Fourthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the average photon path estimation method for diffuse light propagation within biological tissue as described above.

[0017] According to the specific embodiments provided in this application, this application has the following technical effects: This application provides a method, device, medium, and product for estimating the average photon path of diffuse light propagating within biological tissue. The method includes: acquiring experimental data of the tested tissue under a combined photodetector setup; the experimental data includes the propagation path lengths and corresponding detection intensities of several photon packets; selecting two sequence numbers from the photon packet sequence numbers to determine a path interval; the path interval includes all photon packets between the two selected sequence numbers; calculating the slope of the path interval based on the detection intensities and propagation path lengths of each photon packet within the path interval; using the slope as an estimate of the tissue absorption coefficient; calculating the emission intensity of each photon packet based on the estimated tissue absorption coefficient, the propagation path length of each photon packet, and the corresponding detection intensity; and calculating the average photon path based on the emission intensity, detection intensity, and estimated tissue absorption coefficient of all photon packets. This application abandons the traditional approach of direct arithmetic averaging or simple weighted averaging, and instead indirectly and robustly estimates the tissue absorption coefficient by selecting a representative path interval and calculating its slope. This method starts from the original definition of average photon path, uses the estimated absorption coefficient to deduce the emission intensity of the light source, and finally calculates the average path. This process is closer to the physical model of photon attenuation in tissues, thus significantly overcoming the problem of systematic overestimation or underestimation in traditional methods, and obtaining a more accurate estimate of the average photon path. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is an application environment diagram of an average photon path estimation method for diffuse light propagation within biological tissue, as described in one embodiment of this application.

[0020] Figure 2 This is a flowchart illustrating a method for estimating the average photon path of diffuse light propagating within biological tissue, as provided in an embodiment of this application.

[0021] Figure 3This is a distribution diagram of photon path length obtained by Monte Carlo simulation, provided as an embodiment of this application. The horizontal axis represents the path length of the photon packet, and the vertical axis represents the normalized photon packet energy.

[0022] Figure 4 This is a schematic diagram illustrating the transmission path of a photon packet within a tissue in a given source-detector combination (optical detector combination), provided as an embodiment of this application. There are many possible transmission paths for the photon packet within this optical detector combination; the diagram shows the transmission path of one such photon packet.

[0023] Figure 5 This diagram illustrates the average photon path length calculated in this embodiment of the present application, and the average photon path length obtained by the "gold standard" and conventional methods (direct averaging and weighted averaging) in comparison.

[0024] Figure 6 This is a schematic diagram of the overall process for accurately estimating the average photon path of diffuse light propagating within biological tissue, as provided in an embodiment of this application.

[0025] Figure 7 This is a schematic diagram of a tissue model (cylinder, simulating skeletal muscle tissue in the arm, leg, etc.) provided in an embodiment of this application. A pair of photodetectors are arranged on the surface of the cylinder. Photon packets are emitted by the light source into the tissue and received by the detectors through the photon transmission path (i.e., optical measurement is achieved).

[0026] Figure 8 This is a schematic diagram illustrating the numerical relationship between the photon packet pathlength and the logarithm of photon packet energy provided in an embodiment of this application, showing the slope of the fitted straight line. Sl These are key variables in this application.

[0027] Figure 9 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] The physical principle of blood oxygen measurement mainly involves modifying Beer-Lambert's law, that is, at a specific wavelength ( λ The change in tissue absorption coefficient obtained under diffused light irradiation, given a light source-detector combination (light-detector combination). Δμ a ( λ The change in optical density divided by the average path length of a photon is expressed mathematically as follows: Δμ a ( λ )= ΔOD ( λ ) / MPL ( λ (); Here the optical density changes ΔOD ( λ ) for a specific time ( t The logarithmic change in detection intensity relative to the baseline time, i.e. ΔOD ( λ )=ln( I dB ( λ ) / I dt ( λ ));here I dB and I dt Baseline time and t The detection intensity at a given moment is the sum of the detection energies of all photon packets. MPL This is the average photon path length among the different photon path lengths of the photodetector combination, i.e., the average photon path.

[0030] From the above formula, it can be seen that at different times obtained through experiments ( t Accurate estimation of average photon path under photon detection intensity conditions (at both time and baseline time) MPL This is a crucial step in accurately measuring changes in tissue absorbance and blood oxygenation. The calculations below all use a wavelength of [wavelength value missing]. λ The diffuse light is therefore omitted in the following formulas. λ This variable.

[0031] According to the original definition, the formula for accurately obtaining the average photon path is: MPL 0 = ln(I s / I d ) / μ a ;here I s and I d These are the light source intensity (i.e., the sum of the emission intensity of all photon packets) and the detection intensity (i.e., the sum of the detection intensity of all photon packets), respectively. μ a The absorption coefficient is the tissue absorption coefficient. Since the above formula only has... I d Experimental data (i.e., information about all probe photon packets) can be obtained through optical measurements, therefore MPL 0 cannot be obtained through optical measurement, but it can be used as the "gold standard" to test other estimation methods through computer simulation.

[0032] For experimental data obtained from optical measurements (i.e., probe photon packet information), there are traditionally two methods for estimating MPL. The first method is to estimate the MPL for all probe photon packets (let's say...). n The algebraic average of the transmission path lengths is calculated as follows: ; here( L 1, L 2,..., L n This refers to the transmission path length for each photon packet. Based on theoretical derivation and examples, this method overestimates the actual average photon path length, i.e.: MPL 1 >MPL 0.

[0033] The second method is to analyze all the detector photon packets (i.e., the detector intensity, denoted as ) n (each) is weighted and summed according to the normalized photon packet energy over the transmission path length, i.e. ; here( w 1, w 2,..., w n The normalized energy of each photon packet, i.e. .

[0034] As can be seen from theoretical derivation and examples, this method will underestimate the actual average photon path, that is: MPL 2 <MPL 0.

[0035] As can be seen from the above, traditional photon average path estimation methods overestimate or underestimate the actual value, resulting in errors in blood oxygenation measurements. This application starts from the original definition of photon average path, first accurately estimating the intermediate variable (i.e., the tissue absorption coefficient), and then calculating the photon average path from this estimate, thus avoiding overestimation or underestimation of the actual value. This application introduces a slope... Sl This intermediate variable can effectively reduce the error in estimating changes in tissue blood oxygen concentration.

[0036] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] The method for estimating the average photon path of diffuse light propagating within biological tissues provided in this application embodiment can be applied to, for example... Figure 1 In the application environment shown, terminal 102 communicates with server 104 via a network. A data storage system can store the data that server 104 needs to process. The data storage system can be set up independently, integrated into server 104, or placed in the cloud or on another server.

[0038] The terminal 102 can be, but is not limited to, various desktop computers, laptops, smartphones, tablets, IoT devices, and portable wearable devices. IoT devices can include smart speakers, smart TVs, smart air conditioners, and smart in-vehicle devices. Portable wearable devices can include smartwatches, smart bracelets, and head-mounted devices. The server 104 can be implemented using a standalone server or a server cluster composed of multiple servers, or it can be a cloud server.

[0039] In one exemplary embodiment, such as Figure 2 As shown, a method for estimating the average photon path of diffuse light propagating within biological tissue is provided. This method is executed by a computer device, specifically a terminal or server, or both. In this embodiment, the method is applied to... Figure 1 Taking server 104 as an example, the explanation includes the following steps S1 to S6. Wherein: S1. Obtain experimental data of the tissue under test under optical detection combination; the experimental data includes the transmission path length of several photon packets and the corresponding detection intensity.

[0040] The experimental data comprises all photon packets and their corresponding information obtained through optical measurement or computer simulation. The photon packet information includes the photon energy and transmission path length of the photon packet. A photon packet is a combination of photons with the same path. The computer simulation utilizes Monte Carlo simulation to obtain the photon energy and transmission path length of several photon packets within a specified optical detector assembly. The optical detector assembly includes a light source and a detector. The optical detector assembly is placed on the tissue under test. The tissue under test includes the subject's skeletal muscle, brain, breast tissue, etc.

[0041] In this embodiment, a light source-detector combination (optical detector combination) is placed on the tissue surface. For a given optical detector combination, experimental data such as the energy (i.e., detection intensity) and path length of the detected photon packets are obtained. In actual optical measurements, the experimental data is obtained from the photon packet information collected by the detector. In computer simulation, the experimental data consists of all photon packets and their corresponding information after Monte Carlo simulation of the tested tissue; the photon packet information includes the photon energy and transmission path length of the photon packet; the photon packet is a combination of photons with the same path; the Monte Carlo simulation obtains the photon energy and transmission path of several photon packets within a specified optical detector combination; the optical detector combination includes a light source and a detector; the optical detector combination is placed on the tested tissue.

[0042] In this embodiment of the application, a total of [number] arrangements are made on the cylindrical surface of the tested tissue. one In this application, the photon packet energy and photon packet path length can be obtained through Monte Carlo simulation. The process involves placing a light source and a detector on the tissue surface, setting the tissue optical properties, and using a computer to simulate the absorption, scattering, and transmission of photon packets in the tissue model, thereby obtaining the detection intensity and transmission path length of the detected photon packets.

[0043] S2. Select two numbers from the sequence numbers of the photon packets to determine a path interval; the path interval includes all photon packets between the two selected sequence numbers.

[0044] The selection of the two sequence numbers satisfies: 1≤ k 1< k 2 ≤ n; where n is the total number of photon packets. k 1 and k 2 represents the selected sequence number; the path interval includes sequence number... k 1 to k All photon packets between 2.

[0045] In this embodiment, the tissue under this optical detection combination is targeted. n Different photon packet transmission path lengths (L 1, L 2,..., L n ) and photon packet energy (i.e., detection intensity) I d (1), I d (2),..., I d ( n Select two of the serial numbers as k 1 and k 2, such that 1≤ k 1< k 2≤ n .

[0046] S3. Calculate the slope of the path interval based on the detection intensity and transmission path length of each photon packet within the path interval.

[0047] The calculation formula is: ; in, Sl ( k 1, k 2) Represents the slope of the path interval; k 1 and k 2 represents the selected sequence number; I d ( i ) is the first i The detection intensity of each photon packet; L i For the first i The transmission path length of a photon packet; I d ( i+ 1) is the first i+ The detection intensity of a single photon packet; L i+1 For the first i+ The transmission path length of one photon packet.

[0048] S4. Use the slope as an estimate of the tissue absorption coefficient.

[0049] S5. Calculate the emission intensity of each photon packet based on the estimated value of the tissue absorption coefficient, the transmission path length of each photon packet, and the corresponding detection intensity.

[0050] In this embodiment, the emission intensity of each photon packet is estimated based on a modified Beer-Lambert law formula. I s (1), I s (2),..., Is ( n The calculation formula is: ; in, I s ( i ) is the first i The emission intensity of a photon packet; I d ( i ) is the first i The detection intensity of each photon packet; μ a This is an estimate of the tissue absorption coefficient; L i For the first i The transmission path length of a photon packet; Sl ( k 1, k 2) Represents the slope of the path interval.

[0051] S6. Calculate the average photon path based on the emission intensity, detection intensity, and estimated value of the tissue absorption coefficient of all photon packets.

[0052] In this embodiment, the average photon path within the tissue is calculated based on the original definition (i.e., the relationship between photon packet emission intensity and detection intensity). The calculation formula is as follows: ; in, L mean,3 This represents the average photon path; n is the total number of photon packets. I s ( i ) is the first i The emission intensity of a photon packet; I d ( i ) is the first i The detection intensity of each photon packet; μ a This is an estimated value for the tissue absorption coefficient.

[0053] Substituting into the previous formula, that is This is the formula for calculating the final average photon path.

[0054] The method proposed in this application can accurately estimate the average photon path of a given optical detector combination, and can be used to calculate changes in tissue blood oxygenation.

[0055] Thus, this embodiment achieves accurate estimation of the average photon path of diffuse light propagating within biological tissues.

[0056] In this embodiment, the photon path and photon energy were obtained through computer simulation of photon transmission (i.e., photon Monte Carlo simulation), such as... Figure 3 As shown; photon Monte Carlo simulation is implemented using specialized software (e.g., MCX, MCVM), and the optical parameters used in the simulation can be obtained from the literature. Using the calculation method described above in this embodiment, the average photon path of diffuse light propagating within biological tissue is obtained, such as... Figure 4 In the example, the diffuse light wavelength used was 785 nm, and the tissue absorption coefficient was 0.1 cm⁻¹. -1 The cylindrical tissue has a radius of 5 cm and a length of 20 cm; the distance between the light source and the detector is 2.0 cm, and a total of [data missing] were obtained. n =2500 photon packet path length. Please refer to [link / reference]. Figure 5 According to the original definition (i.e., the "gold standard"), the average path of a photon can be calculated as follows: MPL 0 = 16.58 cm. Using the traditional direct averaging method and the weighted averaging method, the average photon paths obtained are respectively... MPL 1 = 24.76cm and MPL 2 = 12.18 cm, with error rates of 49.38% and 26.52% respectively; using the method implemented in the application ( k 1=1, k 2=2500), the average photon path is obtained as MPL The mean path length of photons was 16.77 cm, with an error rate of only 1.14%, achieving accurate estimation of the average photon path.

[0057] The imaging method of this embodiment can be extended to more general situations (i.e., multiple photodetector combinations and various biological tissues and organs) according to actual needs, and can obtain accurate estimation of the average photon path.

[0058] In general, such as Figure 6 As shown, this embodiment provides a method for accurately estimating the average photon path of diffuse light propagating within biological tissue, including the following steps: B1: Irradiating the tissue under test using a light source consisting of a pair of photodetectors and collecting the experimental photon signals using a detector. Please refer to [link to relevant documentation]. Figure 7 B2: Obtain the slope using the method described in step S3. Sl ( k 1, k 2), please refer to Figure 8 B3: Based on the modified Beer-Lambert law formula, using the slope... Sl ( k 1, k 2) Estimate the emission intensity of each photon packet according to method S5. B4: Estimate the average photon path of diffuse light propagating within biological tissue according to the original definition and method S6. This embodiment introduces a slope. SlThis intermediate variable can effectively reduce the error in estimating changes in tissue blood oxygen concentration.

[0059] In one exemplary embodiment, a computer device is provided, which may be a server or a terminal, and its internal structure diagram may be as follows. Figure 9 As shown, this computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and databases. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communicating with external terminals via a network connection. When the computer program is executed by the processor, it implements a method for estimating the average photon path of diffuse light propagating within biological tissue.

[0060] Those skilled in the art will understand that Figure 9 The structures shown are merely block diagrams of some structures related to the present application and do not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than shown in the figures, or combine certain components, or have different component arrangements. In an exemplary embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0061] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0062] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0063] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Moreover, the collection, use and processing of the relevant data are carried out in compliance with the relevant data protection laws and policies of the country where the location is located, and with the authorization granted by the owner of the corresponding device.

[0064] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0065] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0066] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0067] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for estimating the average photon path of diffuse light propagating within biological tissue, characterized in that, include: Acquire experimental data of the tested tissue under optical detection combination; the experimental data includes the transmission path length of several photon packets and the corresponding detection intensity; Two numbers are selected from the sequence numbers of the photon packets to determine a path interval; the path interval includes all photon packets between the two selected sequence numbers. The slope of the path interval is calculated based on the detection intensity of each photon packet within the path interval and the transmission path length. The slope is used as an estimate of the tissue absorption coefficient; The emission intensity of each photon packet is calculated based on the estimated value of the tissue absorption coefficient, the transmission path length of each photon packet, and the corresponding detection intensity. The average photon path is calculated based on the emission intensity, detection intensity, and estimated tissue absorption coefficient of all photon packets.

2. The method for estimating the average photon path of diffuse light propagating within biological tissue according to claim 1, characterized in that, The selection of the two specified numbers satisfies: 1 ≤ k 1< k 2 ≤ n; where n is the total number of photon packets. k 1 and k 2 represents the selected sequence number; the path interval includes sequence number... k 1 to k All photon packets between 2.

3. The method for estimating the average photon path of diffuse light propagating within biological tissue according to claim 1, characterized in that, Based on the detection intensity of each photon packet within the path interval and the transmission path length, the formula for calculating the slope of the path interval is as follows: ； in, Sl ( k 1, k 2) Represents the slope of the path interval; k 1 and k 2 represents the selected sequence number; I d ( i ) is the first i The detection intensity of each photon packet; L i For the first i The transmission path length of a photon packet; I d ( i+ 1) is the first i+ The detection intensity of a single photon packet; L i+1 For the first i + The transmission path length of one photon packet.

4. The method for estimating the average photon path of diffuse light propagating within biological tissue according to claim 1, characterized in that, Based on the estimated value of the tissue absorption coefficient, the transmission path length of each photon packet, and the corresponding detection intensity, the formula for calculating the emission intensity of each photon packet is as follows: ； in, I s ( i ) is the first i The emission intensity of a photon packet; I d ( i ) is the first i The detection intensity of each photon packet; μ a This is an estimate of the tissue absorption coefficient; L i For the first i The transmission path length of a photon packet; Sl ( k 1, k 2) Represents the slope of the path interval.

5. The method for estimating the average photon path of diffuse light propagating within biological tissue according to claim 1, characterized in that, The formula for calculating the average photon path based on the emission intensity, detection intensity, and estimated value of the tissue absorption coefficient of all photon packets is as follows: ； in, L mean,3 This represents the average photon path; n is the total number of photon packets. I s ( i ) is the first i The emission intensity of a photon packet; I d ( i ) is the first i The detection intensity of each photon packet; μ a This is an estimated value for the tissue absorption coefficient.

6. The method for estimating the average photon path of diffuse light propagating within biological tissue according to claim 1, characterized in that, The experimental data consist of all photon packets and their corresponding information obtained through optical measurement or computer simulation. The photon packet information includes the photon energy and transmission path length of the photon packet. The photon packet is a combination of photons with the same path. The computer simulation is obtained by using Monte Carlo simulation to acquire the photon energy and transmission path length of several photon packets within a specified optical detector assembly. The optical detector assembly includes a light source and a detector. The optical detector assembly is placed on the tissue under test.

7. The method for estimating the average photon path of diffuse light propagating within biological tissue according to claim 1, characterized in that, The tissue being tested is the subject's skeletal muscle, brain, or breast tissue.

8. A computer device, comprising: A memory, a processor, and a computer program stored in the memory and capable of running on the processor, characterized in that the processor executes the computer program to implement the method for estimating the average photon path of diffuse light propagating within biological tissue as described in any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the method for estimating the average photon path of diffuse light propagating within biological tissues as described in any one of claims 1-7.

10. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the method for estimating the average photon path of diffuse light propagating within biological tissues as described in any one of claims 1-7.

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