Fast automatic optical power calibration method and device based on fNIRS equipment

Abstract

The invention discloses a fast automatic optical power calibration method based on fNIRS equipment, and the method comprises the steps: determining an initial optical power level as 2N-1-1, and N represents the power corresponding to the total optical power level of a light source; based on the initial optical power level, performing optical power level iterative calibration by taking 2n as an interval, n being an integer and smaller than N-1; in the iterative calibration process, when the calibration frequency is less than or equal to N-1, comparing the maximum voltage value of all probes around each light source obtained within a first preset time with a first voltage threshold value, and adjusting the optical power level according to a comparison result until the calibration frequency is greater than N-1, and outputting the calibrated optical power level; all the light sources are turned on according to the calibrated optical power level, the maximum voltage value of all the probes around each light source obtained within a second preset duration is compared with a second voltage threshold value, the signal quality of each channel is obtained according to a comparison result, and whether a new round of optical power calibration is started or not is determined according to the signal quality of each channel.

Description

Technical Field

[0001] The present invention relates to a fast and automatic optical power calibration method and device based on an fNIRS device. Background Art

[0002] Functional near-infrared spectroscopy (fNIRS) technology is a non-invasive brain science technology means. It indirectly evaluates the brain function status by measuring the metabolic changes (such as oxygenated hemoglobin and deoxygenated hemoglobin in blood vessels) accompanying nerve activities, has good temporal and spatial resolutions, and also has good flexibility and portability, and can be applied to the vast majority of subject groups. Therefore, it has currently become the main technology means for basic brain science research and clinical brain function status evaluation. Each signal channel of the fNIRS device is jointly composed of a transmitting optical pole and a receiving optical pole. The light emitted by the light source passes through the scalp, skull, meninges, cerebrospinal fluid, and gray matter in sequence, scatters and is absorbed therein, and finally is received by the probe. The light power of the light source of the transmitting optical pole, whether the transmitting optical pole and the receiving optical pole are in good contact with the scalp of the subject, the hair volume, scalp oil, and skull thickness at the positions where the transmitting and receiving optical poles are located, etc. will all affect the signal quality.

[0003] Appendix Figure 1 Shown is an arrangement diagram of a near-infrared hat. S represents the light source, which is used to emit two kinds of light with wavelengths of 690nm and 830nm. D represents the probe, which is used to receive the light emitted by the corresponding light source. When the light intensity is not large enough, there will be a phenomenon that the light is not strong enough to be received by the probe after scattering and absorption. Therefore, it is necessary to ensure that the light intensity of each light source is strong enough. At the same time, the device uses an APD (Avalanche Photodiode) to convert the received light into voltage, and the stronger the received light, the greater the voltage. Due to hardware limitations, the voltage that the APD can withstand is limited. That is, when the probe receives the light from different light sources and the APD converts the light into electricity, if the voltage value is greater than the threshold, a saturation phenomenon will occur. In order to ensure a higher signal-to-noise ratio of the received signal for the light at different transmitting light sources and receiving probe positions, and to meet the inconsistent requirements for the light intensity at different positions, it is necessary to reasonably adjust the light intensity of each light source according to the different positions of each channel. However, too high light intensity will also cause the light received by the probe to saturate.

[0004] The magnitude of the light intensity is adjusted by the optical power level, and the optical power level is 0 - 2 N -1, a total of 2 NFor each level, the traditional method is to sequentially try different levels so that the light does not saturate under the premise of being strong enough. However, this method not only consumes computational power but also increases the calculation time (usually taking 30 - 60 seconds or even longer), which does not conform to the actual application scenario. In addition, when the user adjusts the position of the optode, real-time automatic calibration cannot be performed according to the latest signal situation, and a new round of calibration needs to be restarted, which is time-consuming and laborious. Summary of the Invention

[0005] To solve the problem of long calibration time for optical power levels, the present invention provides a fast automatic optical power calibration method based on an fNIRS device. By means of semi-iteration, the optical power levels of different wavelengths of each light source are quickly determined, significantly reducing the number of adjustments, greatly improving the calculation efficiency, and performing real-time operation and update. To solve the problem of long calibration time for optical power levels, the present invention provides a fast automatic optical power calibration method based on an fNIRS device. By means of semi-iteration, the optical power levels of different wavelengths of each light source are quickly determined, significantly reducing the number of adjustments, greatly improving the calculation efficiency, and performing real-time operation and update.

[0006] According to one aspect of the specification of the present invention, there is provided a fast automatic optical power calibration method based on an fNIRS device, including: Determine the initial optical power level as 2 N-1 -1, where N represents the power corresponding to the total optical power level of the light source; Based on the initial optical power level, perform iterative calibration of the optical power level at intervals of 2 n , where n is an integer and less than N - 1; During the iterative calibration process, when the number of calibration times is less than or equal to N - 1, compare the maximum voltage value of all probes around each light source obtained within the first preset duration with the first voltage threshold, and adjust the optical power level according to the comparison result until the number of calibration times is greater than N - 1, and then output the calibrated optical power level; Turn on all light sources with the calibrated optical power level, compare the maximum voltage value of all probes around each light source obtained within the second preset duration with the second voltage threshold, and obtain the signal quality of each channel according to the comparison result, and then determine whether to start a new round of optical power calibration according to the signal quality of each channel.

[0007] As a further technical solution, the method further includes: Obtain the total optical power level of the light source, and use the optical power level at the half position of the total optical power level as the initial optical power level.

[0008] As a further technical solution, the method further includes: Adjust the optical power levels of two wavelengths of each light source respectively.

[0009] As a further technical solution, the method further includes: Set the initial optical power level of the first wavelength of the light source, and turn off all light sources emitting light of the first wavelength; Set the initial optical power level of the second wavelength of the light source, and turn off all light sources emitting light of the second wavelength; Turn on all light sources emitting light of the first wavelength, and based on the set initial optical power level of the first wavelength, perform iterative calibration of the optical power level at intervals of 2 n until the final optical power level corresponding to the first wavelength is obtained; Turn off all light sources emitting light of the first wavelength, turn on all light sources emitting light of the second wavelength, and based on the set initial optical power level of the second wavelength, perform iterative calibration of the optical power level at intervals of 2 n until the final optical power level corresponding to the second wavelength is obtained.

[0010] As a further technical solution, adjusting the optical power level according to the comparison result further includes: When the maximum voltage of all probes around each light source obtained within the first preset time period is greater than or equal to the first voltage threshold, lower the 2 n interval, where n is the power in the previous iterative calibration process minus one; When the maximum voltage of all probes around each light source obtained within the first preset time period is less than the first voltage threshold, increase the 2 n interval, where n is the power in the previous iterative calibration process minus one.

[0011] As a further technical solution, the calibrated optical power level is:

[0012] where ± represents adding or subtracting according to the comparison result between the maximum voltage corresponding to the current optical power level and the first voltage threshold.

[0013] As a further technical solution, comparing the maximum voltage of all probes around each light source obtained within the second preset time period with the second voltage threshold further includes: When the maximum voltage of all probes around each light source obtained within the second preset time period is greater than or equal to the second voltage threshold, it is regarded that the light source is saturated, and a new round of optical power calibration is started.

[0014] As a further technical solution, obtaining the signal quality of each channel according to the comparison result further includes: When the maximum voltage of all the probes around each light source obtained within the second preset duration is less than the second voltage threshold, compare the original light intensity of the current optical power level within the set duration with the light intensity threshold, and when the original light intensity is less than or equal to the light intensity threshold, start a new round of optical power calibration.

[0015] According to one aspect of the specification of the present invention, there is provided a fast automatic optical power calibration device based on an fNIRS device, including: A first main module for determining that the initial optical power level is 2 N-1 -1, where N represents the power corresponding to the total optical power level of the light source; A second main module for performing iterative calibration of the optical power level at an interval of 2 n for n being an integer and less than N - 1; A third main module for, during the iterative calibration process, when the number of calibration times is less than or equal to N - 1, comparing the maximum voltage of all the probes around each light source obtained within the first preset duration with the first voltage threshold, and adjusting the optical power level according to the comparison result until the number of calibration times is greater than N - 1, and then outputting the calibrated optical power level; A fourth main module for turning on all the light sources at the calibrated optical power level, comparing the maximum voltage of all the probes around each light source obtained within the second preset duration with the second voltage threshold, obtaining the signal quality of each channel according to the comparison result, and then determining whether to start a new round of optical power calibration according to the signal quality of each channel.

[0016] According to one aspect of the specification of the present invention, there is provided an optical fiber cap configured with the fast automatic optical power calibration device based on the fNIRS device.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention proposes a fast automatic optical power calibration method based on an fNIRS device. By means of a semi-iterative algorithm, the optical power level of each light source is adjusted, which can ensure that the optical power is large enough while the voltage received by each probe does not exceed the threshold, solving the problem of long calibration time for the optical power level.

[0018] 2. Taking the case where the total optical power level is 512 as an example, through the method of the present invention, the traditional 512 adjustments can be reduced to 9 times. The traditional calibration time for one round is 30 - 60 seconds (or even longer), and now the calibration time is only about 5 seconds, improving the calibration efficiency.

[0019] 3. During the traditional calibration process, if the optical pole shakes or the contact is poor, resulting in changes in the calibration environment, recalibration is required to see the signal situation; while the method of the present invention can be calibrated in real time according to the current environment, and will feedback the latest situation in real time when the environment changes, so that the user can quickly adjust. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of an optical fiber cap in the prior art.

[0021] Figure 2 It is a schematic flow chart of a fast automatic optical power calibration method based on an fNIRS device provided by an embodiment of the present invention.

[0022] Figure 3 It is a schematic diagram of fast automatic optical power calibration with a total optical power level of 512 provided by an embodiment of the present invention.

[0023] Figure 4 It is a schematic diagram of a fast automatic optical power calibration device based on an fNIRS device provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0025] In the description of the present invention, "first" and "second" are only used for illustrative purposes and do not limit the order unless otherwise specifically defined.

[0026] Please refer to Figure 2 , an embodiment of the present invention provides a fast automatic optical power calibration method based on an fNIRS device. First, determine that the initial optical power level is 2 N-1 -1, where N represents the power corresponding to the total optical power level of the light source; then, based on the initial optical power level, with 2 nFor interval iterative calibration of the optical power level, n is an integer and less than N - 1; subsequently, during the iterative calibration process, when the calibration times are less than or equal to N - 1, compare the maximum voltage of all the probes around each light source obtained within the first preset duration with the first voltage threshold, and adjust the optical power level according to the comparison result until the calibration times are greater than N - 1, then output the calibrated optical power level; finally, turn on all the light sources with the calibrated optical power level, compare the maximum voltage of all the probes around each light source obtained within the second preset duration with the second voltage threshold, and obtain the signal quality of each channel according to the comparison result, and then determine whether to start a new round of optical power calibration according to the signal quality of each channel.

[0027] The embodiment of the present invention can quickly determine the optical power levels of different wavelengths of each light source through a semi-iterative method, greatly reducing the adjustment times and improving the calculation efficiency. Further, through semi-iterative analysis, the embodiment of the present invention adjusts and updates the optical power level in real time, and timely, accurately and effectively analyzes the optical power level of each kind of light suitable for the current state, improving the equipment stability.

[0028] Please refer to Figure 3 , taking 512 levels from 0 to 511 of the optical power level as an example, using the automatic calibration method of the present invention to adjust the optical power levels of the wavelengths 690nm and 830nm of each light source, including the following steps: 1. Set the optical power levels of all 830nm to 255 and turn off all 830nm light sources.

[0029] 2. Set the optical power levels of all 690nm to 255 and turn off all 690nm light sources. Wait for 200 milliseconds. After the equipment is stable, turn on all 690nm light sources.

[0030] 3. Wait for 100 milliseconds, read the peak voltage of the APD of all the probes around each light source continuously for 10 milliseconds and take the maximum value, and adjust the optical power level according to this voltage value. If this voltage value is greater than or equal to A volts (the hardware upper limit is A + 0.2 volts, reserving 0.2 volts of upper limit redundancy), lower it, otherwise raise it. For example, when the optical power level is 127, the peak voltage measured by the APD is 3 volts (greater than A), then lower it. The lowered optical power level is 255 - 2 7 = 2 8 -1 - 2 7 = 127. If the peak voltage measured by the APD is 1.8 volts (less than A) at this time, then raise it. The raised optical power level is 127 + 2 6 = 191. Repeat the judgment like this until adding or subtracting 2 0 to determine the final optical power level. In summary, the optical power level formula is as follows:

[0031] Wherein, ± indicates addition or subtraction determined according to the voltage at the current optical power level.

[0032] 4. Turn off all 690 nm light sources and turn on all 830 nm light sources.

[0033] 5. Wait for 100 milliseconds, read the peak voltage of all the probe APDs around each light source for 10 consecutive milliseconds and take the maximum value. Adjust the optical power level according to this voltage value. If this voltage value is greater than or equal to A volts, lower it; otherwise, raise it, the same as step 3.

[0034] 6. Turn on all 690 nm light sources. At this time, all 690 nm and 830 nm light sources are fully on.

[0035] 7. Wait for 100 milliseconds, read the peak voltage of all the probe APDs around each light source for 10 milliseconds and take the maximum value. If it is greater than or equal to B volts (B is the upper limit when 690 nm and 830 nm are added together, B = A + 0.2 + A + 0.2 = 2A + 0.4), then the light source is saturated. If it is less than B volts, further judge the signal quality. When the original light intensity value within 2 consecutive seconds is greater than the threshold C (the original light intensity threshold for good signal), the channel color is green indicating good signal. Otherwise, the channel color is red indicating poor signal quality.

[0036] 8. The above steps 1 - 7 are executed in a loop, adjusting the optical power level in a loop and judging the signal quality of any current channel, providing a reference guide for the operator to adjust the optical pole cap.

[0037] Using the above embodiments, the traditional 512 - time optical power level adjustment can be reduced to 9 times, greatly improving the calibration efficiency.

[0038] It should be noted that the time limits such as waiting for 100 milliseconds, reading for 10 milliseconds, waiting for 200 milliseconds, etc. in the above scheme can all be adjusted according to the actual situation and are not limitations to the present invention.

[0039] In other embodiments, for example, taking the optical power level from 0 to 1023 with a total of 1024 levels as an example, using the automatic calibration method of the present invention to adjust the optical power levels of light sources with wavelengths of 690 nm and 830 nm for each light source, the other steps are the same as the previous embodiments, and the optical power level formula is:

[0040] It can be seen that using the method of the present invention, the traditional 1024 - time optical power level adjustment can be reduced to 10 times, greatly improving the calibration efficiency.

[0041] The implementation basis of each embodiment of the present invention is achieved through programmed processing by a device with processor functions. Therefore, in engineering practice, the technical solutions and functions of each embodiment of the present invention are encapsulated into various modules. Based on this actual situation, on the basis of the above embodiments, an embodiment of the present invention provides a fast automatic optical power calibration device based on an fNIRS device, and this device is used to execute a fast automatic optical power calibration method based on an fNIRS device in the above method embodiments.

[0042] Please refer to Figure 4 , the device includes: a first main module, which is used to determine that the initial optical power level is 2 N-1 -1, where N represents the power corresponding to the total optical power level of the light source; a second main module, which is used to perform iterative calibration of the optical power level at intervals of 2 n , where n is an integer and less than N-1; a third main module, which is used during the iterative calibration process, when the number of calibration times is less than or equal to N-1, compare the maximum voltage of all probes around each light source obtained within the first preset duration with the first voltage threshold, and adjust the optical power level according to the comparison result until the number of calibration times is greater than N-1, and then output the calibrated optical power level; a fourth main module, which is used to turn on all light sources with the calibrated optical power level, compare the maximum voltage of all probes around each light source obtained within the second preset duration with the second voltage threshold, and obtain the signal quality of each channel according to the comparison result, and then determine whether to start a new round of optical power calibration according to the signal quality of each channel.

[0043] A fast automatic optical power calibration device based on an fNIRS device provided by an embodiment of the present invention, aiming at the problem of long calibration time for the optical power level, adopts Figure 4 a number of modules, and quickly determines the optical power levels of different wavelengths of each light source through semi-iteration, greatly reducing the number of adjustments, greatly improving the calculation efficiency, and performing real-time operation and update.

[0044] It should be noted that the device embodiment provided by the present invention, in addition to being used to implement the method in the above method embodiment, is also used to implement the methods in other method embodiments provided by the present invention. The difference is only in setting corresponding functional modules, and its principle is basically the same as that of the above device embodiment provided by the present invention. As long as those skilled in the art, on the basis of the above device embodiment, refer to the specific technical solutions in other method embodiments, obtain corresponding technical means by combining technical features, and the technical solutions constituted by these technical means, and on the premise of ensuring the practicability of the technical solutions, improve the modules in the above device embodiment to obtain corresponding device-like embodiments for implementing the methods in other method-like embodiments. For example: Based on the content of the above device embodiments, as a preferred embodiment, a fast and automatic optical power calibration device based on an fNIRS device provided in the embodiments of the present invention, the first main module is further configured to execute the following instructions: Obtain the total optical power level of the light source, and use the optical power level at the half position of the total optical power level as the initial optical power level.

[0045] Based on the content of the above device embodiments, as a preferred embodiment, a fast and automatic optical power calibration device based on an fNIRS device provided in the embodiments of the present invention, the second main module is further configured to execute the following instructions: Adjust the optical power levels of two wavelengths of each light source respectively.

[0046] Based on the content of the above device embodiments, as a preferred embodiment, a fast and automatic optical power calibration device based on an fNIRS device provided in the embodiments of the present invention, the second main module is further configured to execute the following instructions: Set the initial optical power level of the first wavelength of the light source, and turn off all light sources emitting light of the first wavelength; Set the initial optical power level of the second wavelength of the light source, and turn off all light sources emitting light of the second wavelength; Turn on all light sources emitting light of the first wavelength, and based on the set initial optical power level of the first wavelength, perform iterative calibration of the optical power level at intervals of 2 n until the final optical power level corresponding to the first wavelength is obtained; Turn off all light sources emitting light of the first wavelength, turn on all light sources emitting light of the second wavelength, and based on the set initial optical power level of the second wavelength, perform iterative calibration of the optical power level at intervals of 2 n until the final optical power level corresponding to the second wavelength is obtained.

[0047] Based on the content of the above device embodiments, as a preferred embodiment, a fast and automatic optical power calibration device based on an fNIRS device provided in the embodiments of the present invention, the third main module is further configured to execute the following instructions: When the maximum voltage of all probes around each light source obtained within the first preset duration is greater than or equal to the first voltage threshold, lower the 2 n interval, where n is the power minus one in the previous iterative calibration process; When the maximum voltage of all probes around each light source obtained within the first preset duration is less than the first voltage threshold, increase the 2 n interval, where n is the power minus one in the previous iterative calibration process.

[0048] Based on the content of the above device embodiments, as a preferred embodiment, a fast and automatic optical power calibration device based on an fNIRS device provided in the embodiments of the present invention has an optical power level after calibration as follows:

[0049] Wherein, ± is determined to be plus or minus according to the comparison result between the maximum voltage corresponding to the current optical power level and the first voltage threshold.

[0050] Based on the content of the above device embodiments, as a preferred embodiment, a fast and automatic optical power calibration device based on an fNIRS device provided in the embodiments of the present invention, the fourth main module is further configured to execute the following instructions: When the maximum voltage of all the probes around each light source obtained within the second preset duration is greater than or equal to the second voltage threshold, it is regarded that the light source is saturated, and a new round of optical power calibration is started.

[0051] Based on the content of the above device embodiments, as a preferred embodiment, a fast and automatic optical power calibration device based on an fNIRS device provided in the embodiments of the present invention, the fourth main module is further configured to execute the following instructions: When the maximum voltage of all the probes around each light source obtained within the second preset duration is less than the second voltage threshold, compare the original light intensity of the current optical power level within the set duration with the light intensity threshold, and when the original light intensity is less than or equal to the light intensity threshold, start a new round of optical power calibration.

[0052] Based on the same inventive concept as the above embodiments, the embodiments of the present invention further provide an optical fiber cap configured with the fast and automatic optical power calibration device based on an fNIRS device.

[0053] In summary of the above embodiments, the present invention proposes a semi-iterative algorithm to adjust the optical power level of each light source, which can ensure that the optical power is large enough while the voltage received by each probe does not exceed the threshold, solves the problem of long calibration time for the optical power level, reduces the traditional 512 adjustments to 9 times, and the traditional calibration time for one round is 30 - 60 seconds or even longer, and now the calibration time is only about 5 seconds, improving the calibration efficiency. In addition, during the traditional calibration process, if the optical pole shakes or is in poor contact, etc., resulting in changes in the calibration environment, it is necessary to recalibrate to see the signal situation. However, this algorithm calibrates in real time according to the current environment and will feedback the latest situation in real time when the environment changes, so that the user can quickly adjust.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A fast and automated optical power calibration method based on fNIRS equipment, characterized in that: include: Determine the initial optical power level to be 2 N-1 -1, where N represents the power corresponding to the total optical power level of the light source; Based on the initial optical power level, 2 n Iterative calibration of optical power level is performed at intervals, where n is an integer and is less than N-1; During the iterative calibration process, when the number of calibrations is less than or equal to N-1, the maximum voltage of all probes around each light source obtained within the first preset time period is compared with the first voltage threshold, and the optical power level is adjusted according to the comparison result, until the number of calibrations is greater than N-1, the calibrated optical power level is output; Turn on all light sources at the calibrated optical power level, compare the maximum voltage of all probes around each light source obtained within the second preset time period with the second voltage threshold, and obtain the signal quality of each channel based on the comparison result, and then decide whether to start a new round of optical power calibration based on the signal quality of each channel.

2. According to claim 1, a fast and automated optical power calibration method based on fNIRS equipment is characterized in that: The method further comprises: The total optical power level of the light source is obtained, and the optical power level at a position where the total optical power level is half is taken as the initial optical power level.

3. According to claim 1, a fast and automated optical power calibration method based on fNIRS equipment is characterized in that: The method further comprises: The optical power levels of the two wavelengths of each light source are adjusted separately.

4. According to claim 3, a fast and automated optical power calibration method based on fNIRS equipment is characterized in that: The method further comprises: Setting the initial optical power level of the first wavelength of the light source, and turning off all light sources emitting light of the first wavelength; Setting the initial optical power level of the second wavelength of the light source, and turning off all light sources emitting light of the second wavelength; All light sources emitting light of the first wavelength are turned on, and based on the set initial optical power level of the first wavelength, the power level is increased by 2 n Iteratively calibrating the optical power level for the interval until a final optical power level corresponding to the first wavelength is obtained; All light sources emitting light of the first wavelength are turned off, and all light sources emitting light of the second wavelength are turned on. Based on the set initial optical power level of the second wavelength, the power level of the light of the second wavelength is 2 n The optical power level is iteratively calibrated for an interval until a final optical power level corresponding to the second wavelength is obtained.

5. The method for rapid automated optical power calibration based on fNIRS equipment according to claim 1, characterized in that: Adjusting the optical power level based on the comparison results also includes: When the maximum voltage of all probes around each light source obtained within the first preset time is greater than or equal to the first voltage threshold, the voltage is lowered by 2. n Interval, n is the power in the previous iteration calibration process minus one; When the maximum voltage of all probes around each light source obtained within the first preset time is less than the first voltage threshold, increase by 2 n Interval, where n is the power of the previous iteration calibration process minus one.

6. A fast automated optical power calibration method based on fNIRS equipment according to claim 5, characterized in that: The calibrated optical power levels are: ， Among them, ± indicates that it is determined as plus or minus according to the comparison result between the maximum voltage corresponding to the current optical power level and the first voltage threshold.

7. The method for rapid automated optical power calibration based on fNIRS equipment according to claim 1, characterized in that: Comparing the maximum voltage of all probes around each light source obtained within the second preset time with the second voltage threshold, further comprising: When the maximum voltage of all probes around each light source obtained within the second preset time period is greater than or equal to the second voltage threshold, the light source is regarded as saturated, and a new round of optical power calibration is started.

8. A fast automated optical power calibration method based on fNIRS equipment according to claim 7, characterized in that: The signal quality of each channel is obtained based on the comparison results, including: When the maximum voltage of all probes around each light source obtained within the second preset time period is less than the second voltage threshold, the original light intensity of the current optical power level within the set time period is compared with the light intensity threshold, and when the original light intensity is less than or equal to the light intensity threshold, a new round of optical power calibration is started.

9. A fast and automated optical power calibration device based on fNIRS equipment, characterized in that: include: The first main module is used to determine the initial optical power level as 2 N-1 -1, where N represents the power corresponding to the total optical power level of the light source; The second main module is used to adjust the initial optical power level based on 2 n Iterative calibration of optical power level is performed at intervals, where n is an integer and is less than N-1; The third main module is used for comparing the maximum voltage of all probes around each light source obtained within the first preset time with the first voltage threshold during the iterative calibration process when the number of calibrations is less than or equal to N-1, and adjusting the optical power level according to the comparison result until the number of calibrations is greater than N-1, and then outputting the calibrated optical power level; The fourth main module is used to turn on all light sources at the calibrated optical power level, compare the maximum voltage of all probes around each light source obtained within the second preset time period with the second voltage threshold, and obtain the signal quality of each channel based on the comparison result, and then decide whether to start a new round of optical power calibration based on the signal quality of each channel.

10. An optical fiber cap, characterized in that: The invention is provided with the fast automated optical power calibration device based on fNIRS equipment as claimed in claim 9.

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