WO2024244191A1 - Spectrometer, spectral reconstruction method and computer device - Google Patents

Abstract

A spectrometer, a spectral reconstruction method and a computer device. The spectrometer comprises: a light source; at least one broad spectral response filter, which has an input end and an output end, the input end thereof receiving the light source, wherein in response to a spectrum of the light source, the broad spectral response filter outputs, according to a preset response rule, different modulation spectrums at the output end thereof, so as to irradiate a sample to be tested; and at least one photoelectric detector, which is used for collecting scattered or transmitted light intensity information of said sample after being irradiated by different modulation spectrums. The spectrometer can reduce the loss of a light source during link transmission, thus reducing the power consumption of the light source, increasing a signal-to-noise ratio of a received signal of a detector, and improving the battery life of a device.

Description

A spectrometer, spectrum reconstruction method, and computer equipment Technical Field

The present invention relates to the technical field of spectrum detection, and in particular to a spectrometer, a spectrum reconstruction method, and a computer device.

Background Art

The spectral characteristics of a substance contain a large amount of information, which can be used to detect the composition of the substance in physics and chemistry, and to detect pathological information of the body in biology.

Traditional spectral characteristic detection methods are usually achieved through swept lasers or spectrometers.

The working principle of the swept laser detection method is that the laser outputs a single wavelength, obtains the scattering or absorption information of a single wavelength by irradiating the sample to be tested and collecting the scattered or transmitted light, and then scans each wavelength through the sweep function of the swept laser to obtain the characteristic information of the entire spectrum. This method requires scanning wavelength by wavelength. When the number of required wavelength points is large, the working time will increase significantly. On the one hand, the time cost increases, and on the other hand, it is not suitable for some samples that change rapidly. The price of swept lasers is also relatively expensive, and the size and mass are large. If the wavelength range of the required spectral information is large, a single swept laser may not be able to meet the application requirements, which will further increase the cost, volume and mass.

The working principle of the spectrometer detection method is to use a wide-spectrum light source to illuminate the sample, and the scattered or transmitted light is collected and enters the spectrometer. The intensity information of light of different wavelengths is obtained through the spectrometer, so as to infer the scattering and absorption characteristics of the sample. A spectrometer using this structure will have certain losses in the process of collecting scattered or transmitted light entering the spectrometer. For this type of spectrometer, its wide-spectrum light source is mostly independently powered. Even if there is a large loss in the optical link transmission, it can be compensated by increasing the power of the light source, and it will not affect the detection.

Although computational reconstruction spectrometers can be set up in some miniaturized, portable or wearable devices To reduce the size, but in some cases the same problem mentioned above still exists. Limited by the size of the device and the battery capacity, it is an urgent problem for technicians in this field to ensure the reliability of the detection results and reduce the power consumption of the light source and improve the battery life of the device.

Summary of the invention

The present invention aims to solve one of the technical problems in the related art to a certain extent. To this end, the present invention provides a spectrometer, a spectrum reconstruction method, and a computer device, which can reduce the loss of the light source in the link transmission, thereby reducing the power consumption of the light source and improving the endurance of the device.

In order to achieve the above object, the present invention adopts the following technical solutions in the first aspect:

A computational reconstruction spectrometer, comprising:

light source;

At least one wide spectrum response filter, the wide spectrum response filter having an input end and an output end, wherein the input end receives the light source; the wide spectrum response filter responds to the spectrum of the light source and outputs different modulated spectra at its output end according to a pre-made response rule to irradiate the sample to be tested; and

At least one photodetector is used to collect scattered or transmitted light intensity information of the sample to be tested after being irradiated with different modulated spectra.

In the prior art, after the light source passes through the sample to be tested, the scattered light cannot enter the filter through the slit or optical fiber in a concentrated and directed manner due to the disorder and increased optical expansion, resulting in link loss. Compared with the prior art, the computational reconstruction spectrometer of the present invention, when in use, because the light source is relatively orderly and has a small optical expansion, it can enter the wide spectrum response filter through the optical waveguide almost losslessly, either directly or after being modulated (through some optical elements). The wide spectrum response filter outputs different modulated spectra according to pre-made response rules and irradiates the sample to be tested. Although the light beam will be scattered when passing through the sample to be tested, and its disorder and optical expansion increase, it can still be received by the photodetector. Each photodetector can measure light signals of different wavelengths and convert them into electrical signals. By setting up multiple photodetectors for two A 3D array or a one-dimensional array (such as a ring or a parabola) can increase the coverage area and range, so that scattered light at different angles passing through the sample (or samples) to be tested can be detected as much as possible. Therefore, this solution can reduce the loss of light in the transmission link, so that more light can enter the wide-spectrum response filter and be fully received by the photodetector after being scattered by the sample to be tested. The utilization rate of light in the whole process is improved, and the endurance of the equipment is also improved due to the reduction of light source energy consumption.

The present invention is further preferably provided with an optical window for placing the sample to be tested between the output end of the wide spectrum response filter and the photodetector; the output end of the wide spectrum response filter faces the optical window at an illumination angle to generate scattered light on the surface of the sample to be tested; the photodetector is arranged around the illumination center of the output end of the wide spectrum response filter on the optical window to receive scattered light intensity information; the angle between the direction of the photodetector to the illumination center and the optical window is the receiving angle, and the receiving angle is (0°, 90°].

In the present invention, the illumination angle is further preferably 90°, and the photodetector surrounds the periphery of the wide spectrum response filter.

In the present invention, it is further preferred that a space for placing the sample to be tested is provided between the output end of the wide spectrum response filter and the photodetector, and the output end of the wide spectrum response filter generates transmitted light through the sample to be tested in the space.

The present invention is further preferably that the wide spectrum response filter is a tunable filter, and only one wide spectrum response filter is provided; when in use, the tunable filter can form multiple optical channels in time sequence through multiple tunings to output different modulation spectra to establish the spectral response matrix.

In the present invention, it is further preferred that the wide spectrum response filter is a filter with an optical waveguide structure.

In the present invention, it is further preferred that the filter of the optical waveguide structure is a Fabry-Perot filter.

In the present invention, it is further preferred that the filter of the optical waveguide structure is a Bragg grating filter.

The present invention is further preferably that the filter of the optical waveguide structure is a Mach-Zehnder interference filter Wave device.

The present invention is further preferably configured on a miniaturized, portable or wearable device when in use.

It is further preferred that the filter of the optical waveguide structure is a filter of a single-mode waveguide structure.

It is further preferred that the filter of the optical waveguide structure is a filter of a multimode waveguide structure.

The optical etendue of waveguide filters is lower, and the orderliness of photons coupled into the waveguide is higher, so the coupling efficiency is more significantly improved. Measured by optical etendue, their relationship is: single-mode waveguide < multi-mode waveguide < slit.

The present invention is further preferably that the photodetector is a planar photodetector, and the photodetector is only provided with one. A planar photodetector is a special type of photodetector, also known as a planar array photodetector. It is composed of a plurality of photodetector units, which are arranged on a two-dimensional plane to form an array structure. Each unit can independently measure the optical signal and convert it into an electrical signal.

Compared with photodetector arrays, surface photodetectors have the advantages of high spatial resolution, real-time imaging, easy integration and high sensitivity.

Since the surface photodetectors are arranged in two dimensions, they can provide higher spatial resolution; surface photodetectors can acquire two-dimensional image data in real time, and they can simultaneously capture the entire image in a short time; surface photodetectors usually integrate multiple photodetector units on a chip, and this integrated structure makes them more compact and convenient to use, and can be easily integrated with other electronic devices and systems; surface photodetectors improve sensitivity by measuring multiple light signals at the same time. These light signals can enter the photodetector unit from different angles or positions, thereby enhancing the ability to receive light. Therefore, surface photodetectors can also be set on a hemispherical surface with the irradiation center of the sample to be tested as the sphere center to receive light at different angles. of scattered light.

It should be noted that, in fact, a planar photodetector can be regarded as a special case of a photodetector array, that is, photodetectors arranged on a two-dimensional plane.

It is further preferred that the spectral width of the light source is above 200 nm, 500 nm or 1000 nm.

It is further preferred that the light sources are all SLED light sources, and all the SLED light sources cover the range of the spectrum width when working simultaneously.

The present invention is further preferably provided with a first lens at the output end of the wide spectrum response filter to increase the light intensity of the modulated spectrum on the sample to be measured; or, provided with a second lens before the photodetector to enable the photodetector to collect light in a larger spatial range.

In addition, the present invention also provides a spectral calculation and reconstruction method in the second aspect, including constructing a spectral response matrix, establishing an underdetermined set of equations, solving the underdetermined set of equations and spectral reconstruction; wherein the spectral response matrix and the underdetermined set of equations are respectively established by the spectrometer described in the first aspect.

The spectrum calculation and reconstruction method provided by the present invention is similar to the beneficial effect reasoning process of the aforementioned spectrometer, and will not be repeated here.

Furthermore, the present invention further provides a computer device in a third aspect, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the spectral calculation and reconstruction method as described in the second aspect when executing the computer program.

These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. The best embodiments or means of the present invention will be described in detail in conjunction with the drawings, but they are not intended to limit the technical solutions of the present invention. In addition, there are multiple features, elements, and components that appear in each of the following texts and drawings, and different symbols or numbers are marked for convenience, but they all represent components with the same or similar structures or functions.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described below in conjunction with the accompanying drawings:

FIG1 is a schematic diagram of the principle of the spectrometer described in the present invention.

FIG. 2 is a schematic diagram of the structure of a spectrometer according to an exemplary embodiment, showing a multi-light source and multi-filter structure.

FIG. 3 is a schematic diagram of the structure of a spectrometer according to an exemplary embodiment, showing an adjustable broadband filter and a planar photodetector.

FIG4 is a schematic structural diagram of a spectrometer in an exemplary embodiment, showing a spectrometer applied to a smart watch or a wristband.

FIG5 is a schematic diagram of the structure of the spectrometer in an exemplary embodiment, showing how to implement time-division multiplexing of a broadband light source and a photodetector by switching filters.

DETAILED DESCRIPTION

Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments in the implementation manner are intended to be used to explain the present invention and should not be construed as limiting the present invention.

References in this specification to "one embodiment" or "an example" or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment itself may be included in at least one embodiment of the present patent disclosure. The appearance of the phrase "in one embodiment" in various places in the specification does not necessarily refer to the same embodiment.

The light source of the existing spectrometer has a large loss during the link transmission process. The inventor found that the principle of the spectrometer determines that the light beam must enter the spectrometer from a very small size in order to effectively distinguish the spectral information. The input end of the commonly used spectrometer is usually made into a slit or optical fiber. The light beam will be scattered after passing through the sample, and its disorder and optical expansion will increase, resulting in a large loss of coupling into the slit or optical fiber. Energy, which means that the detector array at the receiving end must have very high sensitivity and responsiveness. On the one hand, this places extremely high demands on the detector array, which will increase the cost. On the other hand, due to link loss, the resolution of weak transmitted or scattered light is very poor.

The general spectrometer solution requires the light source to illuminate the sample to be tested, which will produce scattered light. Due to the disorder and increased optical expansion of the scattered light, it cannot be concentrated and directed through the slit or optical fiber to enter the filter, resulting in link loss. The loss is usually between 10% and 99.9%. The smaller the slit or the smaller the optical fiber aperture, the higher the resolution, and the greater the loss. For the application of photonic chip spectrometers, especially computational reconstruction spectrometers, it is necessary to couple the spatial diffraction light into a single-mode optical fiber or waveguide, and its loss can be above 99%. If the above-mentioned computational reconstruction spectrometer is integrated into a miniaturized, portable or wearable device, it will also be a serious test for battery life, which will seriously hinder its application in miniaturized, portable or wearable devices.

As shown in FIG. 1 , this embodiment proposes a computational reconstruction spectrometer, including a light source, at least one wide-spectrum response filter, at least one photodetector, and a working area for placing a sample to be tested.

The working area is arranged at the output end of the wide spectrum response filter, which can also be said to be the case that the wide spectrum response filter is placed before the sample to be tested. The light generated by the wide spectrum light source directly or after being modulated (through some optical elements) first enters the wide spectrum response filter through an optical waveguide, then irradiates the sample to be tested and is scattered, and finally is received by a photodetector.

In this process, the order of light in the original link transmission process is changed. The light source produces relatively orderly light with small optical expansion, which passes through the optical waveguide almost losslessly into the wide spectrum response filter. Then, by setting up multiple photodetectors in a two-dimensional array or one-dimensional array (such as a ring or parabola), the coverage area or range can be increased, so that as much scattered light passing through the sample to be tested can be detected as much as possible.

Therefore, the loss of light in the transmission link can be reduced, allowing more light to enter the wide-spectrum response filter and be fully received by the photodetector after being scattered by the sample to be tested. The utilization rate of light in the whole process is improved, and the battery life is also improved due to the reduction in light source energy consumption.

In some embodiments, if the wide spectrum response filter used is a spatial coupling filter, its loss can be ignored. In other embodiments, if the wide spectrum response filter adopts an integrated photonic chip, its coupling loss is less than 30%. The huge difference in loss leads to different tolerance to noise. For example, the noise introduced by the photodetector and circuit is 20dB on the filter pre-structure spectrometer, and the noise introduced in the general spectrometer may be 2dB (1:70 signal intensity), which is a great degradation of the spectrometer indicators. The traditional solution is to improve the light source, PD (photodetector), or circuit, which requires the light source optical power to increase 70 times or the PD and circuit noise to reduce 70 times to achieve the same effect. The invention can solve the above problems by only changing the position of the filter.

Therefore, the scheme of the present invention greatly improves the performance of the spectrometer, and will have a beneficial effect in any field where the spectrometer can be applied, especially in the field of weak spectrum detection. Specific fields may include spectral analysis in the field of communications, spectral monitoring of harmful gases, spectral monitoring of water quality, spectral monitoring of various substances in the human body (blood oxygen, blood lactate, blood sugar, blood lipids, etc.), and spectral monitoring of soil.

The specific implementations of the light source, the wide spectrum response filter and the photodetector are described in detail below.

In a specific embodiment, the light source adopts a broad spectrum light source, and its spectrum width can be designed to be above 60nm, above 200nm, or above 500nm, or above 1000nm. The broad spectrum light source includes a plurality of light sources located in different wavelength ranges and capable of working independently of each other. According to the needs of the actual application scenario, several of them can be selectively combined to work. In some embodiments, the light source can also adopt a single light source with a narrow spectrum width, which can also be selected according to the actual situation for the specific application.

As shown in FIG2 , the wide spectrum light source is preferably a plurality of SLED light sources, and all the SLED light sources cover the range of the spectrum width when working simultaneously. SLED is the abbreviation of Superluminescent Light Emitting Diode, which is a special type of light emitting diode. Compared with traditional light emitting diodes (LEDs), SLEDs have a wider spectrum bandwidth and higher brightness.

The working principle of SLED is similar to that of LED, but it is different in structure. It is usually composed of a series of semiconductor material layers, including a light-emitting layer and a light-reflecting layer. This structure generates light by stimulated radiation when an excitation current passes through it. Due to the optical enhancement mechanism in SLED, it can provide a wider spectral bandwidth and higher output power than ordinary LEDs.

The wavelength range of SLED depends on its specific design and manufacturing. Common SLED wavelength ranges include visible light, near infrared light, and mid-infrared light. In the visible light range, the wavelength of SLED is usually between 400 nanometers and 700 nanometers. In the near infrared range, the wavelength can extend from 800 nanometers to thousands of nanometers. For the mid-infrared range, the wavelength can extend from a few micrometers to more than ten micrometers.

It should be noted that the specific SLED wavelength range depends on factors such as material selection, device structure and manufacturing process. Different SLED products may have different wavelength ranges and output power characteristics, so the present invention needs to make appropriate selections according to application requirements when selecting and using them.

In some embodiments, the spectrometer is configured on a miniaturized, portable or wearable device, the wide spectrum response filter has an input end and an output end, and its input end is connected to the wide spectrum light source through an optical waveguide. The wide spectrum response filter is configured to receive and respond to the spectrum of the wide spectrum light source through the optical waveguide, and output different modulated spectra at its output end according to a pre-made response rule.

In order to reduce the number of wide spectrum response filters and the space occupied in the chip, as shown in Figure 3, in some embodiments, the wide spectrum response filter is a tunable filter, and only one wide spectrum response filter may be provided. When in use, the tunable filter can form multiple optical channels in time sequence through multiple tunings to output different modulation spectra to establish the spectrum response matrix.

Tunable filters can use liquid crystal filters (Liquid Crystal Filters), which use the electro-optical effect of liquid crystal materials to adjust the spectral range passing through the filter. By controlling the applied voltage, the wavelength range can be adjusted. Liquid crystal filters can be adjusted within a wide wavelength range and have high optical transmittance and modulation speed.

Tunable filters can also use acousto-optic tunable filters (AOTF), which use the acousto-optic effect to adjust the transmission characteristics of light. It changes the refractive index of light by applying acoustic vibrations, thereby achieving wavelength selection. AOTF can be quickly and accurately adjusted over a wide range of wavelengths.

Tunable filters can also use thermal tunable filters, which are devices that use thermal effects to change the optical properties of the filter. They usually use heat sources and temperature control systems to change the operating temperature of the filter, thereby adjusting its transmission or reflection characteristics.

In some exemplary embodiments, the wide spectrum response filter is a filter of an optical waveguide structure. The filter of the optical waveguide structure is a Fabry-Perot filter. The Fabry-Perot filter uses the interference effect between optical waveguides to achieve filtering function. It is composed of an air cavity between two reflectors, at least one of which is translucent. By adjusting the cavity length or changing the transmittance of the reflector, light of a specific wavelength can be selectively transmitted or reflected.

As one of the above alternative embodiments, the filter of the optical waveguide structure can also be a Bragg grating filter. The Bragg grating filter uses a periodic refractive index modulation structure to selectively reflect or transmit light of a specific wavelength through the Bragg reflection effect. This filter is usually composed of a periodic refractive index modulation area on an optical waveguide, and different filtering characteristics can be achieved by changing the period and depth of the refractive index modulation area.

As one of the above alternative embodiments, the filter of the optical waveguide structure can also be a Mach-Zehnder interference filter. The Mach-Zehnder interference filter uses the interference effect in the optical waveguide to achieve the filtering function. It consists of a beam splitter, two optical waveguide transmission paths and a recoupler. By adjusting the path length or phase difference, light of a specific wavelength can be selectively transmitted or reflected.

It should be noted that the wide spectrum response filter here refers to a filter having a wide spectral width range of the response spectrum. The wide spectrum response filter includes a plurality of filters arranged in space or a filter that is adjustable in time sequence. If the spectral width of the spectrum is X, and the corresponding spectral width of n spatially arranged wide spectrum response filters is X ₁ -X _n , then X ₁ ∪X ₂ ∪…∪X _n ≥X; if the spectral width of the spectrum is X, an adjustable filter can modulate n filters with corresponding spectral widths of X ₁ -X _n in time sequence, then X ₁ ∪X ₂ ∪…∪X _n ≥X is also satisfied.

The photodetector is used to collect the scattered or transmitted light intensity information of the sample to be tested after being irradiated with different modulated spectra. In order to collect the scattered light at different angles, multiple photodetectors are arranged in a two-dimensional array or a one-dimensional array (such as a ring or a parabola), which can increase the coverage area (range) so that as much scattered light as possible passing through the sample to be tested (or sample) can be detected. In some embodiments, the photodetector is a surface photodetector, see Figures 3 and 4, the surface photodetector can be regarded as a special case of a photodetector array, that is, a photodetector arranged on a two-dimensional plane, so there can be only one photodetector.

It should be noted that, as shown in FIG5 , when only one surface photodetector is used, it may correspond to multiple channels or multiple wide-spectrum filters. By switching the wide-spectrum filters, time-sharing multiplexing of the wide-spectrum light source and the photodetector can be achieved. This can not only improve the signal strength, but also ensure that the spectral distribution of the light source and the response distribution of the photodetector are completely consistent, further increasing the signal-to-noise ratio and obtaining better spectral recovery results.

It should be noted that there are two implementation methods for the spatial arrangement of the wide spectrum response filter, the working area, and the photodetector. Referring to Figures 1-3, one is to set the working area between the output end of the wide spectrum response filter and the photodetector, and the spectrum coming out of the wide spectrum response filter can directly pass through the sample to be tested and generate transmitted light to be detected by the photodetector. In the specific implementation, a channel space can be set at the output end of the wide spectrum response filter and the photodetector to form the working area so that the sample to be tested can enter. This is mainly used to detect transparent or translucent samples, such as gases and liquids.

Referring to FIG4 , another method is to set an optical window between the output end of the wide spectrum response filter and the photodetector. In specific implementation, transparent glass can be used as the optical window. The working area is used to place the sample to be tested. This situation is mainly used when the sample to be tested cannot be destroyed or divided. For example, the spectrometer is configured on a smart watch to detect the composition of a substance in the subcutaneous blood vessels of the human body. The sample to be tested can only be used as an inhomogeneous medium or particle. When the light encounters the microstructure, particles or other scattering centers inside the material, the light deviates or changes the propagation direction in all directions. These scattered lights can be collected by photodetectors.

It should be noted that, in some exemplary embodiments, a first lens may be provided between the output end of the wide spectrum response filter and the sample to be tested to focus or collimate the light, so that the light irradiated to the sample to be tested is stronger, and the area will be more concentrated when scattered, which is helpful to obtain a scattering spectrum with better uniformity. In addition, a second lens may be provided between the sample to be tested and the photodetector to focus the light, so as to collect light in a larger spatial range onto the photodetector, thereby increasing the signal-to-noise ratio.

In addition, during the use of the spectrometer, the light source will be used to irradiate the human skin. Since the adaptability of the human skin has a threshold, there will be a small amount of loss of the light source after passing through the filter. The spectrometer with the filter in front can not only reduce the intensity of the light source, but also make full use of the loss of the filter to reduce the stimulation of the light source to the human skin. The existing spectrometer that uses the light source to pass through the sample to be tested first will undoubtedly increase the intensity of irradiation on the human skin because it requires a high-power light source. Excessive irradiation will cause discomfort to people with sensitive skin, and even cause a burning sensation.

In some exemplary embodiments, a working surface for attaching a sample to be tested is provided on one side of the transparent glass, and the working area is located on the side where the working surface is located. The output end of the wide spectrum response filter faces the working surface at an illumination angle, and the photodetector is arranged around the illumination center of the output end of the wide spectrum response filter on the working surface.

The illumination angle is the angle between the direction from the output end of the wide spectrum response filter to the illumination center and the working surface. The angle between the direction from the photodetector to the illumination center and the working surface is the receiving angle, which is (0°, 90°).

More specifically, the illumination angle is 90°, and the photodetector surrounds the periphery of the wide spectrum response filter. The photodetector is a surface photodetector, which is an annular surface and is on a hemispherical surface with the illumination center of the sample to be tested as the sphere center.

As an alternative embodiment, the illumination angle is 45°, and the photodetector is half-surrounded on one side of the wide spectrum response filter. As shown in FIG4 , only the photodetector in which the illumination angle and the receiving angle are on the same plane is used as an example for explanation, and the receiving angle in the figure is taken as 45° as an example.

This embodiment also provides a spectrum calculation and reconstruction method, including constructing a spectrum response matrix, establishing an underdetermined equation group, solving the underdetermined equation group and spectrum reconstruction, wherein the spectrum response matrix and the underdetermined equation group are respectively established by the above-mentioned spectrometer.

Constructing the spectral response matrix: First, a set of samples of known input spectra need to be obtained through experiments or simulations, and the corresponding output signals need to be measured. These input spectra can be a series of samples of known wavelengths and light intensities. By simulating or experimentally measuring the input spectra through the optical system of the computational reconstruction spectrometer, the corresponding output signals can be obtained. These input spectra and the corresponding output signals are used as data to construct a spectral response matrix.

Establishing an underdetermined system of equations: Based on the principle of computational reconstruction spectrometer and the spectral response matrix, an underdetermined system of equations can be established. The unknown quantity of the system of equations is the spectrum of the sample to be measured, and the equations of the system of equations come from the relationship between the input spectrum and the output signal, which is mapped through the spectral response matrix.

Solving underdetermined equations: Since the equations are underdetermined, that is, the unknowns (the spectra of the samples to be measured) are more than the number of equations, they cannot be solved directly. In this case, appropriate mathematical methods are needed to solve the equations. Common solution methods include least squares method, regularization method, etc.

Spectral reconstruction: By solving the underdetermined equations, the spectrum estimation result of the sample to be tested can be obtained. This estimation result can represent the spectrum information of the sample to be tested under the computational reconstruction spectrometer.

The working principle is described in detail below in conjunction with a specific embodiment. As shown in Figure 1, the spectrometer includes a broadband light source (non-laser light source, 3dB bandwidth>1nm), multiple broadband filters, samples to be tested, and multiple photodetectors. The broadband light source passes through different broadband filters, and the spectrum is modulated. Different modulated spectra are absorbed or scattered by the sample after irradiating the sample, and the light intensity signal is collected by a photodetector, i.e., PD.

Mathematically, the spectral range to be detected is decomposed into multiple segments, corresponding to (λ1, λ2, λ3, ... λn).

The intensity distribution of a broadband light source on the spectrum is represented by a vector (A _λ1 ,A _λ2 ,A _λ3 ,...A _λn );

The filtering curve of the wide spectrum filter is represented by the vector (f _λ1 ,f _λ2 ,f _λ3 ,...f _λn );

The spectral characteristics of the sample to be tested are represented by the vector (X _λ1 ,X _λ2 ,X _λ3 ,...X _λn );

The response curve of the photodetector is represented by the vector (D _λ1 , D _λ2 , D _λ3 , ... D _λn ).

The light emitted by the broadband light source passes through the broadband filter and its intensity is modulated to (A _λ1 f _λ1 ,A _λ2 f _λ2 ,A _λ3 f _λ3 ,...A _λn f _λn ),

After the spectrum curve to be measured passes through the sample to be measured, the spectrum information changes again, which is expressed by (A _λ1 f _λ1 X _λ1 ,A _λ2 f _λ2 X _λ2 ,A _λ3 f _λ3 X _λ3 ,...A _λn f _λn X _λn );

This information is collected by the photodetector and reflected as an electrical signal with a strength of Among them, A _λn D _λn f _λn is determined by the device selected by the system and is a known item. To simplify the description, this parameter is subsequently expressed by _Sn . X _λn is the spectral characteristic of the property to be measured and is an unknown item.

If there are m groups of wide spectrum filters that collect the detection light intensity of each group of wide spectrum filters, we can get a set of equations represented by the following matrix:

in It is a parameter determined by the system. In addition to the characteristics of the system components, it is mainly determined by the design of each filter. is the spectral characteristic to be measured, The value detected by the detector.

Studies have shown that when m<<n, by constructing the matrix Make them have good uncorrelation, and solve It is obvious that m represents the number of filters or channels required, and n represents the resolution of the spectral characteristics. This shows that by designing the filtering characteristics of each filter, only a very small number of filters or channels are needed to obtain very high-resolution spectral characteristics.

At the same time, this embodiment also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above-mentioned spectrum calculation and reconstruction method when executing the computer program. Here, the computer device can be a wearable device such as a smart watch, a smart bracelet, a smart helmet, etc.

Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. Accordingly, the computer program can be stored in a non-volatile computer-readable storage medium, and when the computer program is executed, the method of any of the above-mentioned embodiments can be implemented.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims (12)

A computational reconstruction spectrometer, characterized in that it comprises: light source; At least one wide spectrum response filter, the wide spectrum response filter having an input end and an output end, wherein the input end receives the light source; the wide spectrum response filter responds to the spectrum of the light source and outputs different modulated spectra at its output end according to a pre-made response rule to illuminate the sample to be tested; and At least one photodetector is used to collect scattered or transmitted light intensity information of the sample to be tested after being irradiated with different modulated spectra. The spectrometer according to claim 1 is characterized in that an optical window for placing a sample to be tested is provided between the output end of the wide spectrum response filter and the photodetector; the output end of the wide spectrum response filter faces the optical window at an illumination angle to generate scattered light on the surface of the sample to be tested; the photodetector is arranged around the illumination center of the output end of the wide spectrum response filter on the optical window to receive scattered light intensity information; the angle between the direction from the photodetector to the illumination center and the optical window is the receiving angle, and the receiving angle is (0°, 90°]. The spectrometer according to claim 2, characterized in that the illumination angle is 90° and the photodetector surrounds the periphery of the wide spectrum response filter. The spectrometer according to claim 1 is characterized in that a space for placing the sample to be tested is provided between the output end of the wide spectrum response filter and the photodetector, and the output end of the wide spectrum response filter generates transmitted light through the sample to be tested in the space. The spectrometer according to claim 1 is characterized in that the wide spectrum response filter is a tunable filter, and only one of the wide spectrum response filters is provided; when in use, the tunable filter can form multiple optical channels in time sequence through multiple tunings to output different modulation spectra to establish the spectral response matrix. The spectrometer according to claim 1, characterized in that the wide spectrum response filter is a filter with an optical waveguide structure. The spectrometer according to claim 1, characterized in that the photodetector is a surface photodetector. The spectrometer according to claim 1 is characterized in that it is configured on a miniaturized, portable or wearable device when in use. The spectrometer according to claim 1, characterized in that the light sources are all SLED light sources. The spectrometer according to claim 1 is characterized in that a first lens is provided at the output end of the wide spectrum response filter to increase the light intensity of the modulated spectrum on the sample to be measured; or a second lens is provided before the photodetector so that the photodetector can collect light in a larger spatial range. A spectral calculation and reconstruction method comprises constructing a spectral response matrix, establishing an underdetermined set of equations, solving the underdetermined set of equations and spectral reconstruction; wherein the spectral response matrix and the underdetermined set of equations are respectively established by the spectrometer described in any one of claims 1-10. A computer device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the spectral calculation and reconstruction method described in claim 11 when executing the computer program.