A method and device for collecting light scattering signals of particles

Abstract

The present invention belongs to the field of particulate optical sensing, and specifically relates to a particulate light scattering signal acquisition method and device, comprising: controlling scattered light of different scattering angles generated by a particulate matter to be measured to reach a digital micromirror device (DMD); utilizing the on and off states of each micromirror in the DMD to allow scattered light of different scattering angle combinations to reach a photodetector, thereby realizing multiple acquisitions of scattered light signal intensity by the photodetector to obtain a measurement signal vector S; wherein, when a single micromirror is on, the scattered light reaching the micromirror is focused on the photodetector through the micromirror according to a preset optical path; when the single micromirror is off, the scattered light reaching the micromirror is diverged to an area outside the photodetector; for X=(ΦΨ) ‑1 S is minimized by 1 norm to determine X and the sparse domain Ψ; and the scattered light intensity P at different scattering angles generated by the measured particles is obtained by inversion according to P=ΨX. The present invention can improve the collection efficiency of the spatial distribution of scattered light intensity.

Description

Technical Field

[0001] The present invention belongs to the field of particle optical sensing, and more specifically, relates to a method and device for collecting particle light scattering signals. Background Art

[0002] Particulate matter plays a vital role in human production and daily life, being closely intertwined with our daily lives. In some industrial processes, optical methods are required to obtain information about particulate matter in order to accurately assess its properties. In specific applications, such as fire detection, optical scattering is required to obtain particle size information for more accurate fire alarms. Furthermore, optical scattering is also used to sense atmospheric particulate matter, such as in PM2.5 particle measurement. Therefore, optical scattering sensing is a crucial means for obtaining information about particulate matter and is of great significance to our comprehensive understanding of the environment in which we live.

[0003] Given the significant significance of particulate matter, years of development have resulted in the development of a wide variety of instruments and equipment using different technical principles, and the relevant technical principles for measuring particle size distribution have also made significant progress. Sympatec's HELOS, a German company, obtains particle size distribution information by measuring multi-channel Furanhofer diffraction light signals. While these instruments have demonstrated good accuracy in practical applications, their complex and sophisticated structure generally results in a large and expensive size, further limiting their application in outdoor measurements and widespread adoption.

[0004] Chinese invention patent specification CN109856019A discloses a particle information sensing method based on near-field scattering. This method utilizes near-field scattering technology to establish a relationship between scattered light intensity and particle information, thereby obtaining particle information measurements. Chinese invention patent publication number CN107677573A also discloses a multi-angle particle information detection method. Multiple photoelectric converters are employed to receive scattered light signals from particles at different angles, thereby sensing particle size information. Both invention patents employ optical measurement methods. Optical methods have garnered widespread attention in the industry due to their non-destructive and rapid measurement speeds. Research has shown that the key to ensuring the measurement accuracy and resolution of optical methods lies in acquiring scattered light signals with a higher number of channels and higher angular resolution. Because the final particle information measurement results must be derived by inversely analyzing the collected light signals, acquiring higher-dimensional scattered light signals is crucial for optical measurement methods. Similar perspectives are expressed in the descriptions of the aforementioned two Chinese patents. The former uses microlenses to collect and receive near-field scattered light, aiming to extract high-dimensional scattered light signals with higher angular resolution from the resulting image. While the patent disclosure does not provide a detailed schematic diagram of the sensor structure, the description and analysis of the results show that the angular spectrum bandwidth of the extracted scattered light signal is concentrated only within a narrow forward range of approximately 180 degrees. Therefore, the collected scattered light signal is somewhat monotonous. The latter, on the other hand, directly collects high-dimensional scattered light signals by placing a fixed or rotating array of photoelectric receivers. While this design is structurally simple to implement, it results in a more complex hardware structure and a trade-off between measurement accuracy and structural complexity. Higher measurement accuracy requires more photoelectric receivers, which further increases structural complexity. An optional simplification proposed in the disclosure is to place the photoelectric receivers on a rotating disk. When collecting scattered light signals, the rotating disk is used to obtain scattered light signals at different angles. However, another problem with this approach is that the stability of the particles to be measured must be ensured. Otherwise, the light signals collected by the photodetectors at different measurement angles will correspond to particles in different states, which will introduce significant errors when later inverting the particle information. The schematic diagram in the published document shows that the target dispersion system to be measured in this patent is a liquid dispersion system. While this can increase the stability of the particles to be measured, it also brings limitations to the scope of application and is not conducive to measurement operations.

[0005] Furthermore, Chinese patent CN110553955A discloses a method for measuring particle size distribution based on a scattered light field, employing a CCD to receive high-resolution, forward-to-backward scattered light angular spectrum information over a wide range. This method requires a complex imaging structure design, employing a parabolic reflector and three lenses to shape the scattered light signal and reduce it to image on the CCD. Furthermore, this method's imaging speed is limited by the CCD's performance, such as frame rate and response wavelength, making it unsuitable for multi-wavelength imaging of scattered light. Summary of the Invention

[0006] In response to the defects and improvement needs of the existing technology, the present invention provides a method and device for collecting particulate matter light scattering signals, the purpose of which is to improve the collection efficiency of the spatial distribution of scattered light intensity.

[0007] To achieve the above objectives, according to one aspect of the present invention, a method for collecting light scattering signals from particles is provided, comprising:

[0008] The method controls the amount of scattered light at different scattering angles generated by the particles being measured to reach the digital micromirror device (DMD). By switching the micromirrors in the DMD to on and off, the scattered light with different scattering angle combinations reaches the photodetector, enabling the photodetector to collect scattered light signal intensities multiple times to obtain a measurement signal vector S. Each element in S represents the total intensity of the scattered light at the corresponding scattering angle combination. When a single micromirror is on, the scattered light reaching that micromirror is focused on the photodetector through the micromirror along a preset optical path. When a single micromirror is off, the scattered light reaching that micromirror is dispersed beyond the photodetector.

[0009] For X = (ΦΨ) -1 The 1-norm of S is minimized to determine X and the sparse domain Ψ. The scattered light intensity P at different scattering angles produced by the measured particles is inverted according to P = ΨX to realize the acquisition of particle light scattering signals. Here, Φ represents the measurement matrix, and the value of each row element represents the on / off state of each micromirror in the DMD, corresponding to a single acquisition of the scattered light signal intensity by the photodetector.

[0010] Furthermore, the measurement matrix is ​​an orthogonal and symmetric matrix.

[0011] Furthermore, the measurement matrix is ​​determined by the Hadamard matrix to realize the control of the switching state of each micromirror in the DMD.

[0012] The present invention also provides a particle light scattering signal acquisition device, comprising: a light source, a reflector, a digital micromirror device (DMD), a photodetector, and a processor;

[0013] The reflector is used to reflect scattered light of different scattering angles generated by the particles to be measured so that it reaches the digital micromirror device (DMD). The digital micromirror device (DMD) switches between the on and off states of each micromirror so that scattered light of different scattering angle combinations reaches the photodetector, thereby realizing multiple acquisitions of scattered light signal intensity by the photodetector to obtain a measurement signal vector S. Each element in S is the total intensity of the scattered light under the corresponding scattering angle combination. When a single micromirror is on, the scattered light reaching the micromirror will be focused on the photodetector through the micromirror according to a preset optical path. When the single micromirror is off, the scattered light reaching the micromirror will diverge to an area outside the photodetector. The processor is used to calculate X=(ΦΨ) -1 The 1-norm of S is minimized to determine X and the sparse domain Ψ. The scattered light intensity P at different scattering angles produced by the measured particles is inverted according to P = ΨX to realize the acquisition of particle light scattering signals. Here, Φ represents the measurement matrix, and the value of each row element represents the on / off state of each micromirror in the DMD, corresponding to a single acquisition of the scattered light signal intensity by the photodetector.

[0014] Furthermore, the measurement matrix is ​​an orthogonal and symmetric matrix.

[0015] Furthermore, the measurement matrix is ​​determined by the Hadamard matrix to realize the control of the switching state of each micromirror in the DMD.

[0016] Furthermore, the reflector is a rotating ellipsoidal mirror.

[0017] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0018] (1) The present invention proposes a method for collecting light scattering signals of particulate matter. Through optical path design, a wide range of scattered light is focused on a photodetector. During the focusing process, the scattered light is modulated by a DMD (Digital Micromirror Device), and part of the scattered light signal is regularly selected. The rapid flipping of the DMD micromirror enables the photodetector to receive a large amount of scattered light signals S in a short time. Furthermore, for X = (ΦΨ) -1 The 1-norm of S is minimized to determine X and the sparse domain Ψ. The scattered light intensity P at different scattering angles generated by the measured particles is inverted according to P = ΨX to realize the acquisition of particle light scattering signals. Here, Φ represents the measurement matrix, and the value of each row element represents the on / off state of each micromirror in the DMD, corresponding to a single acquisition of the scattered light signal intensity by the photodetector, thereby realizing high-resolution scattered light signal acquisition.

[0019] (2) The present invention proposes to use a Hadamard matrix as the measurement matrix. The Hadamard matrix has the characteristics of orthogonality and symmetry. That is, an n-dimensional Hadamard matrix contains N orthogonal vectors, where N also represents the number of sampling times. When the value of N is small, the dimension of the sampled signal is also small, which means that the resolution of the sampled scattered light signal is also low. When the value of N is large, the dimension of the sampled signal is also large, which means that the resolution of the sampled scattered light signal is also high. The orthogonal Hadamard matrix has the characteristics of simple generation and good imaging effect. It can be generated in real time on hardware and is suitable for the fast flipping of DMD. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A flowchart of a method for collecting light scattering signals of particles provided by an embodiment of the present invention;

[0021] Figure 2 A spatial distribution diagram of scattered light signals provided by an embodiment of the present invention;

[0022] Figure 3 A diagram of the scattered light single-pixel imaging structure provided by an embodiment of the present invention;

[0023] Figure 4 A single-angle scattered light signal diffusion diagram provided by an embodiment of the present invention;

[0024] Figure 5 An optical structure diagram of an optimized particle light scattering signal acquisition device provided in an embodiment of the present invention;

[0025] Figure 6 A physical diagram of the particle light scattering signal acquisition device provided in an embodiment of the present invention;

[0026] Figure 7 Flowchart of the device for collecting scattered light signals provided by an embodiment of the present invention;

[0027] Figure 8 Comparison diagram of scattered light signals and simulation results provided by an embodiment of the present invention; wherein A is a measured scattered light image, B is a comparison diagram of the measured and simulated scattered light signals, and C is a schematic diagram of the relative error between the measured and simulated scattered light signals;

[0028] Figure 9 The scattered light images collected at different resolutions provided by the embodiment of the present invention; among them, A is a scattered light image with a resolution of 16×16, B is a scattered light image with a resolution of 32×32, and C is a scattered light image with a resolution of 64×64. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0030] Example 1

[0031] A method for collecting light scattering signals of particles, such as Figure 1 Shown, including:

[0032] The method controls the amount of scattered light at different scattering angles generated by the particles being measured to reach the digital micromirror device (DMD). By switching the micromirrors in the DMD to on and off, the scattered light with different scattering angle combinations reaches the photodetector, enabling the photodetector to collect scattered light signal intensities multiple times to obtain a measurement signal vector S. Each element in S represents the total intensity of the scattered light at the corresponding scattering angle combination. When a single micromirror is on, the scattered light reaching that micromirror is focused on the photodetector through the micromirror along a preset optical path. When a single micromirror is off, the scattered light reaching that micromirror is dispersed beyond the photodetector.

[0033] For X = (ΦΨ) -1 The 1-norm of S is minimized to determine X and the sparse domain Ψ. The scattered light intensity P at different scattering angles produced by the measured particles is inverted according to P = ΨX to realize the acquisition of particle light scattering signals. Here, Φ represents the measurement matrix, and the value of each row element represents the on / off state of each micromirror in the DMD, corresponding to a single acquisition of the scattered light signal intensity by the photodetector.

[0034] This paper proposes a novel method for collecting particle light scattering signals. Specifically, it uses imaging to capture multidimensional particle light scattering signals, obtaining optical characterizations of particle information and enabling rapid acquisition of the spatial distribution of scattered light intensity. Through careful optical path design, a wide range of scattered light is focused onto a photodetector. During the focusing process, the scattered light is modulated by a DMD (Digital Micromirror Device), regularly selecting portions of the scattered light signal. Furthermore, the rapid flipping of the DMD micromirrors enables the photodetector to receive a large amount of scattered light signals in a short period of time, enabling high-resolution scattered light signal acquisition.

[0035] According to scattering theory, the spatial distribution of scattered light intensity is related to a lot of information about particles (such as refractive index and particle size distribution), and is an important way to sense particle information. The scattered light intensity of particles can be described as:

[0036] P=C N∫f(d)q(d,m,λ,θ)dd

[0037] Among them, C N is the particle number concentration, f(d) is the particle size distribution function, q(d,m,λ,θ) is the scattering coefficient of a single particle, d is the particle diameter, m is the particle's refractive index, λ is the wavelength of the incident light, and θ is the observation angle of the scattered light signal. As can be seen, the scattered light intensity varies depending on the wavelength λ and the observation angle θ, resulting in inconsistent optical characteristics. These characteristics are crucial for particle sensing. Therefore, high-resolution particle scattered light acquisition is a crucial foundation for accurate particle sensing. The spatial distribution of scattered light is closely related to the observation angle θ, making spatially distributed scattered light acquisition a crucial approach for sensing particle information.

[0038] The spatial distribution of scattered light collection is to project the scattered light intensity onto the imaging device through imaging, and form a high-resolution scattered light field image with spatial relationship, such as Figure 2 As shown. The existing CCD-based imaging method is to shape the scattered light through an optical lens, and finally project it onto a CCD of matching size. This measurement method is limited by the performance of the CCD, such as the CCD frame rate and the response wavelength range, making it difficult to quickly and accurately measure the scattered light signal. To this end, the present invention proposes a method and system for scattered light collection based on single-pixel imaging. Single-pixel imaging can receive scattered light signals by using a high-performance photodetector as a detection unit. Compared with CCD, high-performance photodetectors are lower in cost and can quickly and accurately receive scattered light signals. Therefore, the present invention adopts a single-pixel imaging method to collect scattered light signals.

[0039] In addition to high-performance photodetectors, this embodiment uses DMD as a spatial modulator to modulate scattered light in different directions, which is eventually received by the photodetector. There are multiple miniature aluminum and closely arranged reflectors on the DMD, and each micromirror has three states, namely, a diagonal rotation of 12° (called "on"), a diagonal rotation of 0° (called "flat"), and a diagonal rotation of -12° (called "off"). The orderly flipping of the different states of the micromirrors will selectively modulate the scattered light in different directions, so the scattered light signals received by the photodetector in different flip states of the DMD are different. In addition, since the flip rate of the DMD can reach up to 22KHz, the DMD can complete the state switching in a short time, realizing the rapid acquisition of high-resolution scattered light signals.

[0040] According to the single-pixel imaging theory, the scattered light signal P projected on the DMD is modulated by the flip state described by the measurement matrix Φ and becomes the photodetector received signal S, which can be specifically described as: S = ΦP.

[0041] Since the states of the micromirrors on the DMD are limited, this embodiment requires the use of a binary measurement matrix. It is preferred that the measurement matrix is ​​an orthogonal and symmetric matrix. It is further preferred that the measurement matrix Φ is determined by the Hadamard matrix to achieve control of the switching state of each micromirror in the DMD.

[0042] The Hadamard matrix has the characteristics of orthogonality and symmetry, that is, an n-dimensional Hadamard matrix contains N orthogonal vectors, where N also represents the number of sampling times; when the value of N is small, the dimension of the sampled signal is also small, which means that the resolution of the sampled scattered light signal is also low; when the value of N is large, the dimension of the sampled signal is also large, which means that the resolution of the sampled scattered light signal is also high. Among them, the high-order Hadamard matrix Among them, H N / 2 It is a Hadamard matrix of dimension N / 2, and the 1-dimensional Hadamard matrix H1=1. The orthogonal Hadamard matrix has the characteristics of simple generation and good imaging effect. It can be generated in real time on hardware and is suitable for fast flipping of DMD.

[0043] In addition, since the spatially distributed scattered light intensity has repeated observation angles θ, the spatially distributed scattered light signal is sparse in a certain domain, which satisfies the compressed sensing compression conditions and enables accurate reconstruction of the scattered light signal. The specific principles are as follows:

[0044] (1) Compression: The compression process requires transforming the scattered signal P through a sparse domain Ψ. After the transformation, most elements of the signal X are 0. The formula is as follows:

[0045] P=ΨX

[0046] (2) Sampling: The sampling process requires that the measurement matrix Φ is uncorrelated with the matrix Ψ composed of the sparse transformation basis. The sampling formula can be expressed as:

[0047] S=ΦΨX

[0048] (3) Reconstruction: The reconstruction process is to reconstruct the scattered light signal P by minimizing the 1-norm of the X signal. The specific formula can be expressed as:

[0049] argmin||X||;stS=ΦΨX

[0050] From the formula S = ΦΨX, we know that X = (ΦΨ) -1 S, and minimize the 1 norm of the X signal, that is, (ΦΨ) -1 S is minimized, thereby finding a sparse domain Ψ that satisfies the 1-norm minimization condition (argmin||X||), and substituting it into X = (ΦΨ) -1 Solve for X in S, and finally substitute Ψ and X into the formula P = ΨX to reconstruct the scattered light signal P.

[0051] The scattered light emitted from the central reaction area over a large spatial range is emitted to the DMD through a rotating elliptical mirror and then focused on the photodetector by the DMD. The DMD is a component composed of many independent tiny mirrors, and the micromirrors on the DMD can be flipped quickly. The micromirrors have three states: on, off, and flat. This embodiment uses the on and off states of the DMD micromirrors. When the micromirrors are on, the scattered light is focused on the photodetector according to a preset optical path. When the micromirrors are off, the scattered light is dispersed to other places except the photodetector. Finally, by quickly opening some DMD micromirrors in a regular manner (Hadamard measurement matrix), some scattered light signals are selected to be focused on the photodetector, and a signal S is measured, as shown in Formula 2. In this embodiment, the measurement matrix is ​​a known Hadamard measurement matrix. Assume that the signal P is the product of the sparse domain matrix Ψ and the signal vector X (compression, formula P = ΨX). The vector X has the meaning of minimum modulus, that is, most elements in X are 0. The physical meaning is that it can be approximately represented by a small amount of information in the matrix Ψ. Based on the formula S = ΦP, the formula S = ΦΨX (substituting the formula P = ΨX into the formula S = ΦP) is further derived. The conversion relationship between S and the signal X, and based on the above-mentioned constraint condition of the minimum modulus of the vector X, ΦΨ can be further obtained. Wherein, the measurement matrix Φ is a preset Hadamard matrix. Therefore, Ψ can be solved. After the signal vector X and Ψ are obtained, the scattered light signal can be finally obtained.

[0052] Example 2

[0053] A particle light scattering signal acquisition device, comprising: a light source, a reflector, a digital micromirror device (DMD), a photodetector, and a processor;

[0054] The reflector is used to reflect scattered light of different scattering angles generated by the particles to be measured so that it reaches the digital micromirror device (DMD). The digital micromirror device (DMD) switches between the on and off states of each micromirror so that scattered light of different scattering angle combinations reaches the photodetector, thereby realizing multiple acquisitions of scattered light signal intensity by the photodetector to obtain a measurement signal vector S. Each element in S is the total intensity of the scattered light under the corresponding scattering angle combination. When a single micromirror is on, the scattered light reaching the micromirror will be focused on the photodetector through the micromirror according to a preset optical path. When the single micromirror is off, the scattered light reaching the micromirror will diverge to an area outside the photodetector. The processor is used to calculate X=(ΦΨ) -1 The 1-norm of S is minimized to determine X and the sparse domain Ψ. The scattered light intensity P at different scattering angles produced by the measured particles is inverted according to P = ΨX to realize the acquisition of particle light scattering signals. Here, Φ represents the measurement matrix, and the value of each row element represents the on / off state of each micromirror in the DMD, corresponding to a single acquisition of the scattered light signal intensity by the photodetector.

[0055] Preferably, the measurement matrix is ​​an orthogonal and symmetric matrix. Further preferably, the measurement matrix is ​​determined by a Hadamard matrix to achieve control of the switching state of each micromirror in the DMD. The relevant technical solution is the same as that of Example 1 and will not be repeated here.

[0056] Since single-pixel imaging uses a single photodetector to receive scattered light signals, it is necessary to focus scattered light signals emitted in different directions on the photodetector. To this end, preferably, this embodiment designs a rotating ellipsoid mirror suitable for scattered light single-pixel imaging, such as Figure 3 As shown. The scattered light in different directions in space is first reflected by the ellipsoidal mirror, then projected onto the DMD, and then reflected by the DMD, and finally focused on the photodetector. However, since the actual reaction area of ​​the scattered light is not an ideal point, if the reaction area is set as a sphere with a diameter of millimeters, the focusing effect of the scattered light in different directions will be different, such as Figure 4 The undesirable imaging diagram shown. In order to accurately obtain the scattered light signal, the present invention improves the imaging quality of the scattered light by optimizing the optical path. Specifically, under the set reaction area and device size restrictions, the ellipsoidal surface parameters and the position of each component are reasonably adjusted to meet the requirements that the scattered light signal in a certain area can be focused in a small area and can be received by the photodetector. The final designed optical path version is as follows Figure 5 Specifically, the ellipsoidal surface parameters of the rotating ellipsoidal mirror include:

[0057] The ellipse equation of the rotating ellipsoidal mirror is The distance between the ellipsoidal cross section and the center of the particle under test is 3.1mm, the cross-sectional aperture is 22.8mm, the distance between the center of the particle under test and the center of the DMD is 12mm, the DMD tilt angle is 12°, and the scattering angle measurement range is 15°-165°. The photodetector is located next to the rotating ellipsoidal mirror and in front of the reflective surface of the DMD micromirror. The angle between the line connecting the DMD center and the photodetector and the line connecting the center of the particle under test and the DMD center is 24°, and the distance between the DMD center and the photodetector is 20.7mm.

[0058] like Figure 6 The picture shown is a real picture. Figure 7 This is a flow chart for the device's collection of scattered light signals. When particulate matter enters the system's scattered light reaction zone, the generated scattered light intensity is focused by an ellipsoidal mirror onto a photodetector. During the measurement process, the micromirrors on the DMD are sequentially flipped according to the Hadamard matrix, and the photodetector records the scattered light intensity data in real time under different DMD modulation states. The scattered light image is reconstructed based on the principles of compressed sensing. Based on geometric relationships, scattered light at the same observation angle is distributed along an arc of the same radius at the left vertex. The scattered light data at the same observation angle are averaged to obtain scattered light signals at different observation angles.

[0059] To evaluate the system performance, the measured scattered light signal was compared with the scattered light signal calculated from the particle spectrometer measurement results, e.g. Figure 8 shown. Figure 8 A in the figure is the scattered light image collected by single-pixel imaging. Figure 8 There are two shadows in A in the figure. The upper left part is the sample nozzle needle, and the middle part is the interference of incident stray light. Due to the influence of noise, some abnormal noise points appear in the image; the appearance of these noise points causes the measured scattered light signal to fluctuate, but the overall trend is still consistent with the theoretical scattered light signal, such as Figure 8 As shown in B. Comparing the theoretical and measured scattered light signals, as shown in Figure 8 As shown in C, the relative error is within ±50%. Figure 9 The scattered light images obtained by sampling the Hadamard matrix with different resolutions are compared with the low resolution ones. Figure 9 A and B in Figure 9 The noise of C in the image is more obvious. Since the scattered light image with higher resolution requires more dimensions of Hadamard matrix measurement, and the intensity of the scattered light signal received each time is smaller, the high resolution image Figure 9 The C in the image shows a lot of noise; this noise likely originates primarily from environmental factors, such as thermal noise from circuit components, surface cleanliness of optical devices, and interference from stray light. Despite the influence of noise, the results in the figure demonstrate that this acquisition method can capture a sufficiently rich scattered light signal. This will allow for future optimization of circuit and structural designs to achieve high-precision and rapid scattered light acquisition.

[0060] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for collecting light scattering signals of particles, characterized in that: include: The method controls the amount of scattered light at different scattering angles generated by the particles being measured to reach the digital micromirror device (DMD). By switching the micromirrors in the DMD to on and off, the scattered light with different scattering angle combinations reaches the photodetector, enabling the photodetector to collect scattered light signal intensities multiple times to obtain a measurement signal vector S. Each element in S represents the total intensity of the scattered light at the corresponding scattering angle combination. When a single micromirror is on, the scattered light reaching that micromirror is focused on the photodetector through the micromirror along a preset optical path. When a single micromirror is off, the scattered light reaching that micromirror is dispersed beyond the photodetector. For X = (ΦΨ) -1 The 1-norm of S is minimized to determine X and the sparse domain Ψ. The scattered light intensity P at different scattering angles produced by the measured particles is inverted according to P = ΨX to realize the acquisition of particle light scattering signals. Here, Φ represents the measurement matrix, and the value of each row element represents the on / off state of each micromirror in the DMD, corresponding to a single acquisition of the scattered light signal intensity by the photodetector.

2. The method for collecting light scattering signals of particles according to claim 1, wherein: The measurement matrix is ​​an orthogonal and symmetric matrix.

3. The method for collecting light scattering signals of particles according to claim 2, wherein: The measurement matrix is ​​determined by the Hadamard matrix to realize the control of the switching state of each micromirror in the DMD.

4. A device for collecting light scattering signals of particles, characterized in that: include: Light source, reflector, digital micromirror device (DMD), photodetector, and processor; The reflector is used to reflect scattered light of different scattering angles generated by the particles to be measured so that it reaches the digital micromirror device (DMD). The digital micromirror device (DMD) switches between the on and off states of each micromirror so that scattered light of different scattering angle combinations reaches the photodetector, thereby realizing multiple acquisitions of scattered light signal intensity by the photodetector to obtain a measurement signal vector S. Each element in S is the total intensity of the scattered light under the corresponding scattering angle combination. When a single micromirror is on, the scattered light reaching the micromirror will be focused on the photodetector through the micromirror according to a preset optical path. When the single micromirror is off, the scattered light reaching the micromirror will diverge to an area outside the photodetector. The processor is used to calculate X=(ΦΨ) -1 The 1-norm of S is minimized to determine X and the sparse domain Ψ. The scattered light intensity P at different scattering angles produced by the measured particles is inverted according to P = ΨX to realize the acquisition of particle light scattering signals. Here, Φ represents the measurement matrix, and the value of each row element represents the on / off state of each micromirror in the DMD, corresponding to a single acquisition of the scattered light signal intensity by the photodetector.

5. The device for collecting particulate matter light scattering signals according to claim 4, characterized in that: The measurement matrix is ​​an orthogonal and symmetric matrix.

6. The device for collecting light scattering signals of particles according to claim 5, characterized in that: The measurement matrix is ​​determined by the Hadamard matrix to realize the control of the switching state of each micromirror in the DMD.

7. The device for collecting light scattering signals of particles according to claim 4, characterized in that: The reflecting mirror is a rotating ellipsoidal mirror.

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