Fast Radiation Imaging System and Method Integrating Optical Imaging and Coding Aperture Technology

Abstract

The present invention relates to the field of radiation imaging technology, and discloses a fast radiation imaging system and method integrating optical imaging and coded aperture technology. The system includes a spectral imaging subsystem and a gamma-ray imaging subsystem. Among them, the spectral imaging subsystem and the gamma-ray imaging subsystem share a coded aperture plate. The gamma-ray imaging subsystem further includes a radiation detector, and the spectral imaging subsystem further includes a first lens, a second lens, a dispersion prism, a third lens and a CCD detector. In the direction from the object to be measured towards the radiation detector and the CCD detector, the arrangement order is successively the first lens, the coded aperture plate, the second lens, the dispersion prism and the third lens. The present invention can perform spectral imaging and radiation imaging simultaneously, reduce the system complexity and cost, and improve the working efficiency and safety.

Description

Technical Field

[0001] The present invention relates to the technical field of radiation imaging, and particularly to a fast radiation imaging system and method integrating optical imaging and coded aperture technology. Background Art

[0002] When supervising mineral resource utilization activities, it is required to safely and efficiently complete the component detection and radioactive level monitoring of mineral raw materials, products or waste residues with a certain stacking range. In this process, it is necessary to perform spectral and radioactive detection on mineral resources, which helps the conduct of trade and the release control of waste residues. On the one hand, there is radioactive pollution in imported industrial products and radioactivity far higher than the natural radioactive background level associated with mineral waste residues. In the process of radioactive detection of metals and minerals, different γ-ray energies emitted by different nuclides can be used to identify the types and relative contents of radioactive elements in substances. While obtaining information such as the types of radioactive nuclides and energy spectra, imaging of the radioactive distribution is performed. On the other hand, through spectral detection technology, not only can the geometric shape of substances be imaged, but also the spectral characteristics of substances can be obtained. Through spectral analysis based on known mineral spectral principles, mineral diagnostic characteristics can be obtained for identification and classification, so as to achieve the purpose of facilitating supervision.

[0003] Currently, the methods for mineral resource monitoring are mainly divided into laboratory measurement and portable types. Laboratory measurement usually performs spot checks on imported minerals or mineral waste residues to make them representative to a certain extent, but there are problems such as large equipment and lack of real-time performance; portable detection methods rely on staff to hold instruments to conduct radioactive inspections on-site at close range, with deficiencies such as low work efficiency, high missed inspection rate, and threat to the health of detection personnel, and are not suitable for radioactive detection of imported minerals and mineral waste residues, etc. And in the existing technology, usually only one type of imaging measurement can be performed simultaneously, and optical imaging and radiation imaging cannot be performed simultaneously, resulting in a longer measurement cycle and low work efficiency.

[0004] Therefore, there is an urgent need for a fast radiation imaging system and method integrating optical imaging and coded aperture technology, which can perform spectral imaging and radiation imaging simultaneously, reduce the system complexity and cost, and improve work efficiency and safety. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a fast radiation imaging system and method integrating optical imaging and coded aperture technology, which can perform spectral imaging and radiation imaging simultaneously, reduce the system complexity and cost, and improve work efficiency and safety.

[0006] The present invention provides a fast radiation imaging system integrating optical imaging and coded aperture technology, including:

[0007] A spectral imaging subsystem and a γ-ray imaging subsystem;

[0008] Among them, the spectral imaging subsystem and the gamma-ray imaging subsystem share a coded aperture plate. The gamma-ray imaging subsystem further includes a radiation detector, and the spectral imaging subsystem further includes a first lens, a second lens, a dispersion prism, a third lens, and a CCD detector;

[0009] In the direction from the object to be measured towards the radiation detector and the CCD detector, the arrangement order is successively the first lens, the coded aperture plate, the second lens, the dispersion prism, and the third lens;

[0010] The object to be measured is used to emit rays and diffusely reflect light;

[0011] The first lens is used to image according to the light diffusely reflected by the object to be measured, so that the object to be measured is imaged on the coded aperture plate through the first lens;

[0012] The coded aperture plate is used to encode rays and light simultaneously;

[0013] The second lens is used to collimate the light after being encoded and modulated onto the dispersion prism;

[0014] The dispersion prism is used to disperse the collimated light according to different wavelengths and inject it into the third lens;

[0015] The third lens is used to converge and image the dispersed light onto the CCD detector;

[0016] The radiation detector is used to receive the rays emitted by the object to be measured;

[0017] The CCD detector is used to receive the light after being converged and imaged by the third lens.

[0018] Furthermore, the difference between the distance between the radiation detector and the object to be measured and the distance between the CCD detector and the object to be measured is less than or equal to a preset error value.

[0019] Furthermore, the CCD detector is arranged in parallel with the third lens.

[0020] Furthermore, the radiation detector is arranged in parallel with the coded aperture plate.

[0021] Furthermore, the CCD detector and the radiation detector are arranged on the same horizontal plane.

[0022] The present invention also provides a fast radiation imaging method integrating optical imaging and coded aperture technology, which is implemented based on the fast radiation imaging system integrating optical imaging and coded aperture technology described in any one of the above, and includes the following steps:

[0023] S1. Image through the first lens according to the light diffusely reflected by the object to be measured;

[0024] S2. Modulate the light imaged on the coded aperture plate through the coded aperture plate;

[0025] S3. Collimate the light after coded modulation through the second lens;

[0026] S4. Disperse the collimated light through the dispersion prism;

[0027] S5. Converge and image the dispersed light through the third lens respectively;

[0028] S6. Receive the spectral information aliased image obtained by the respective converging and imaging of the dispersed light through the CCD detector;

[0029] S7. Reconstruct according to the spectral information aliased image through the compressive sensing reconstruction algorithm to obtain the three-dimensional data spectral information.

[0030] Furthermore, the following steps are also included:

[0031] S1.1. Modulate the rays of the object to be measured radiated on the coded aperture plate through the coded aperture plate;

[0032] S1.2. Receive the ray information aliased image formed by the rays after coded modulation through the radiation detector;

[0033] S1.3. Reconstruct the ray information aliased image through the image reconstruction algorithm to obtain the two-dimensional radioactive source distribution image.

[0034] The present invention has the following technical effects:

[0035] The present invention synchronously modulates the light and rays of the object to be measured by using the same coded aperture plate, respectively receives the light and rays of the object to be measured through the CCD detector and the radiation detector, and then uses the compressive sensing reconstruction algorithm and the image reconstruction algorithm to reconstruct the spectral image and the γ-ray image of the object to be measured respectively. The system structure of this solution combines the functions of spectral imaging and radiation imaging into one, while simplifying the structure of the imaging system as much as possible, reducing the volume and weight. Mounting this imaging system on an unmanned robot platform can quickly complete the spectral and radioactive detection of mineral resources, not only maintaining the high resolution of the measured image, but also achieving fast imaging, while reducing the system complexity and cost, thereby improving the efficiency and safety of the supervision work, and being conducive to the safe and comprehensive utilization of mineral resources. Description of the Drawings

[0036] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings required for the description of the specific embodiments or the prior art. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0037] Figure 1 It is a schematic structural diagram of a fast radiation imaging system integrating optical imaging and coded aperture technology provided by an embodiment of the present invention;

[0038] Figure 2 It is a schematic structural diagram of a spectral imaging subsystem provided by an embodiment of the present invention;

[0039] Figure 3 It is a schematic structural diagram of a γ-ray imaging subsystem provided by an embodiment of the present invention;

[0040] Figure 4 It is a schematic structural diagram of a coded aperture plate provided by an embodiment of the present invention;

[0041] Figure 5 It is a schematic diagram of light being dispersed by a dispersion prism provided by an embodiment of the present invention;

[0042] Figure 6 It is a target pattern and its spectral spectrogram provided by an embodiment of the present invention. Specific Embodiments

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by the present invention.

[0044] The present invention proposes a fast radiation imaging system integrating optical imaging and coded aperture technology, Figure 1 It is a schematic structural diagram of a fast radiation imaging system integrating optical imaging and coded aperture technology provided by an embodiment of the present invention, Figure 2 It is a schematic structural diagram of a spectral imaging subsystem provided by an embodiment of the present invention, Figure 3 It is a schematic structural diagram of a γ-ray imaging subsystem provided by an embodiment of the present invention, Figure 4 It is a schematic structural diagram of a coded aperture plate provided by an embodiment of the present invention. Refer to Figures 1 - 4 , specifically including:

[0045] A spectral imaging subsystem and a γ-ray imaging subsystem;

[0046] Among them, the spectral imaging subsystem and the gamma-ray imaging subsystem share a coded aperture plate. The gamma-ray imaging subsystem further includes a radiation detector, and the spectral imaging subsystem further includes a first lens, a second lens, a dispersion prism, a third lens, and a CCD detector;

[0047] In the direction from the target to be measured towards the radiation detector and the CCD detector, the arrangement order is successively the first lens, the coded aperture plate, the second lens, the dispersion prism, and the third lens;

[0048] The target to be measured is used to emit rays and diffusely reflect light;

[0049] The first lens is used to image according to the light diffusely reflected by the target to be measured, so that the target to be measured is imaged on the coded aperture plate through the first lens;

[0050] The coded aperture plate is used to encode both rays and light;

[0051] The second lens is used to collimate the light after coded modulation onto the dispersion prism;

[0052] The dispersion prism is used to disperse the collimated light according to different wavelengths and inject it into the third lens;

[0053] The third lens is used to converge and image the dispersed light onto the CCD detector;

[0054] The radiation detector is used to receive the rays emitted by the target to be measured;

[0055] The CCD detector is used to receive the light after the third lens converges and images it.

[0056] Among them, the structure of the coded aperture plate can be set according to the specific situation of the target to be measured. While dispersing the light, the dispersion prism can also change the path of the light, so that the rays and the light can be measured simultaneously by different detectors at the same position without interfering with each other.

[0057] Specifically, the parameters of the first lens, the second lens, and the third lens can be set according to the actual situation; the sizes of the first lens and the second lens can be the same, but generally, the third lens is selected as an optical lens / lens with adjustable focal length. And in some embodiments, the third lens can also be assembled with the CCD detector, which is more convenient for image imaging.

[0058] Furthermore, the difference between the distance between the radiation detector and the target to be measured and the distance between the CCD detector and the target to be measured is less than or equal to a preset error value.

[0059] Specifically, the distance between the radiation detector and the target to be measured is substantially equal to the distance between the CCD detector and the target to be measured, which can ensure that the data collected by the radiation detector and the CCD detector are obtained under the same conditions, that is, to ensure spatial consistency and reception time consistency, thereby reducing signal attenuation or perspective change caused by distance difference, reducing data correction work, and further improving the accuracy and reliability of the final analysis result.

[0060] Further, the CCD detector is arranged in parallel with the third lens.

[0061] Specifically, by adjusting the focal length of the third lens or adjusting the distance relationship between the third lens and the CCD detector, the CCD detector can observe the complete coded aperture plate;

[0062] There is no fixed relationship between the angle setting of the third lens and the dispersion prism. As long as the position or angle of the third lens and the dispersion prism is adjusted so that the CCD detector can observe the target to be measured and the coded aperture plate as clearly as possible.

[0063] Further, the radiation detector is arranged in parallel with the coded aperture plate.

[0064] Further, the CCD detector and the radiation detector are arranged on the same horizontal plane.

[0065] Specifically, the CCD detector and the radiation detector are arranged on the same horizontal plane (i.e., placed side by side left and right), and their placement positions are not specifically limited as long as the optical imaging information can be completely observed by the CCD detector. For example, in some embodiments, the dispersion prism can also be inverted, and at this time, the position of the CCD detector is correspondingly adjusted to the other side of the radiation detector.

[0066] Specifically, Figure 5 is a schematic diagram of the light dispersed by the dispersion prism provided by the embodiment of the present invention. Refer to Figure 5 , the dispersion prism can split the incident mixed light according to different wavelengths, so that the split light falls on different pixels of the CCD detector.

[0067] Among them, l is the incident light, i is the incident angle, α is the apex angle of the dispersion prism, γ1 is the refraction angle when the light enters the dispersion prism, γ2 is the refraction angle when the light exits the prism, θ is the exit angle, and Δl represents the imaging area of the incident light projected on the CCD detector. The sum of the refraction angle γ1 and the refraction angle γ2 satisfies:

[0068] ;

[0069] The relationship between the incident angle i and the refraction angle γ1 satisfies:

[0070] ;

[0071] Wherein, λ is the wavelength of the incident light, and n(λ) is the refractive index at different wavelengths;

[0072] The relationship between the exit angle θ and the refraction angle γ2 satisfies:

[0073] ;

[0074] The relationship between the exit angle θ and the incident angle i satisfies:

[0075] .

[0076] Exemplarily, Figure 6 is a target pattern and its spectral spectrogram provided by an embodiment of the present invention. Refer to Figure 6 , select visible light in the range of 450 nm - 650 nm, use the light of 550 nm as the central wavelength of the selected equilateral prism, and calculate the exit angle θ for each wavelength as follows:

[0077] ;

[0078] It can be obtained from the above formula that the incident angle i and the refractive index n(λ) of the dispersion prism determine its exit angle θ, and the distance where the light of different wavelengths falls on the detector is related to the exit angle θ and the distance R from the dispersion prism to the detector.

[0079] The difference between the exit angles of the light of different wavelengths and the exit angle of the central wavelength is p, and the distance d between the positions where the light of different wavelengths is imaged on the detector and the position of the central wavelength is:

[0080] .

[0081] Therefore, in order to make the structure of the imaging system compact and miniaturized, set the distance R between the dispersion prism and the CCD detector to 5 cm, and select 10 discrete spectral segments (450 nm, 462 nm, 475 nm, 490 nm, 508 nm, 528 nm, 551 nm, 578 nm, 608 nm, 642 nm) with the same deflection angle between 450 nm - 650 nm as the spectral dimension of the target spectral data cube, and the spectral spectrogram of the target image can be obtained as shown in Figure 6 shown.

[0082] In the present invention, by using the same encoding aperture plate to synchronously encode and modulate the light and rays of the target to be measured, the light and rays of the target to be measured are respectively received by a CCD detector and a radiation detector. After measurement, the spectral image and γ-ray image of the target to be measured are respectively reconstructed by using a compressive sensing reconstruction algorithm and an image reconstruction algorithm. The system structure of this solution combines the functions of spectral imaging and radiation imaging into one, while simplifying the structure of the imaging system as much as possible, reducing the volume and weight. Mounting this imaging system on an unmanned robot platform can quickly complete the spectral and radioactive detection of mineral resources, maintain the high resolution of the measured image, achieve fast imaging, reduce the system complexity and cost at the same time, thereby improving the efficiency and safety of the supervision work, and being beneficial to the safe and comprehensive utilization of mineral resources.

[0083] The embodiment of the present invention also provides a fast radiation imaging method integrating optical imaging and encoding aperture technology, which is implemented based on the fast radiation imaging system integrating optical imaging and encoding aperture technology described in the above embodiment. Continuing to refer to Figures 1 - 4 , the specific steps for optical imaging are as follows:

[0084] S1. Image the light diffusely reflected by the target to be measured through a first lens.

[0085] S2. Encode and modulate the light imaged on the encoding aperture plate through the encoding aperture plate.

[0086] S3. Collimate the encoded and modulated light through a second lens.

[0087] S4. Disperse the collimated light through a dispersion prism.

[0088] S5. Converge and image the dispersed light respectively through a third lens.

[0089] S6. Receive the spectral information aliased image obtained by the respective converging and imaging of the dispersed light through a CCD detector.

[0090] S7. Reconstruct according to the spectral information aliased image through a compressive sensing reconstruction algorithm to obtain three-dimensional data spectral information.

[0091] Specifically, the three-dimensional data spectral information can reflect the reflection, absorption, and transmission characteristics of the target to be measured at different wavelengths, thereby revealing its material composition, structural characteristics, and chemical properties. The purpose of full-band hyperspectral imaging is to obtain detailed spectral information and image information of the target to be measured in a wider spectral range to improve the recognition accuracy and achieve rapid detection and analysis.

[0092] The specific steps for radiation imaging are as follows:

[0093] S1.1. Modulate the rays of the radiation from the target to be measured on the encoding orifice plate through the encoding orifice plate.

[0094] S1.2. Receive the aliased image of the ray information formed by the modulated rays through a radiation detector.

[0095] S1.3. Reconstruct the aliased image of the ray information through an image reconstruction algorithm to obtain a two-dimensional radiation source distribution image.

[0096] It should be noted that the terms used in the present invention are only for describing specific embodiments and do not limit the scope of the present application. As shown in the specification of the present invention, unless the context clearly indicates an exception, words such as "a", "an", "one" and / or "the" are not specifically singular and may also include plural. The term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or also includes elements inherent to such process, method or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method or device including the said element.

[0097] It should also be noted that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present invention. Unless otherwise clearly specified and defined, terms such as "installed", "connected", "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

[0098] 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 on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention.

Claims

1. A fast radiation imaging system integrating optical imaging and coded aperture technology, characterized in that: include: Spectral imaging subsystem and gamma ray imaging subsystem; The spectral imaging subsystem and the gamma-ray imaging subsystem share a coding aperture plate, the gamma-ray imaging subsystem further includes a radiation detector, and the spectral imaging subsystem further includes a first lens, a second lens, a dispersion prism, a third lens and a CCD detector; From the target to be measured toward the radiation detector and the CCD detector, the arrangement order is the first lens, the coding aperture plate, the second lens, the dispersion prism and the third lens; The target to be measured is used to emit rays and diffusely reflect light; The first lens is used to form an image based on the light diffusely reflected by the target to be measured, so that the target to be measured is imaged on the coding hole plate through the first lens; The coding aperture plate is used to encode the rays and light simultaneously; The second lens is used to collimate the coded modulated light onto the dispersion prism; The dispersion prism is used to split the collimated light into different wavelengths and inject the light into the third lens; The third lens is used to converge the split light and form an image on the CCD detector; The radiation detector is used to receive the radiation emitted by the target to be detected; The CCD detector is used to receive the light after being focused and imaged by the third lens.

2. The rapid radiation imaging system integrating optical imaging and coded aperture technology according to claim 1, characterized in that: The difference between the distance between the radiation detector and the target to be measured and the distance between the CCD detector and the target to be measured is less than or equal to a preset error value.

3. The rapid radiation imaging system integrating optical imaging and coded aperture technology according to claim 2, characterized in that: The CCD detector is arranged in parallel with the third lens.

4. The rapid radiation imaging system integrating optical imaging and coded aperture technology according to claim 3, characterized in that: The radiation detector is arranged in parallel with the coding aperture plate.

5. The rapid radiation imaging system integrating optical imaging and coded aperture technology according to claim 1, characterized in that: The CCD detector and the radiation detector are arranged on the same horizontal plane.

6. A rapid radiation imaging method integrating optical imaging and coded hole technology, based on a rapid radiation imaging system integrating optical imaging and coded hole technology as described in any one of claims 1 to 5, characterized in that: The specific steps include: S1, imaging the light diffusely reflected by the target through the first lens; S2, encoding and modulating the light imaged on the coding aperture plate through the coding aperture plate; S3, collimating the coded modulated light through a second lens; S4, splitting the aligned light through a dispersion prism; S5, the split light rays are respectively converged into images through the third lens; S6, receiving the split light through the CCD detector and converging the light into images to obtain a spectral information aliasing image; S7, reconstructing the spectral information aliasing image by using a compressed sensing reconstruction algorithm to obtain three-dimensional data spectral information; The step of performing radiation imaging is also included: S1.1, encoding and modulating the rays radiated by the target to be measured on the coding aperture plate through the coding aperture plate; S1.2, receiving the coded modulated rays through the radiation detector to form a ray information aliasing image; S1.

3. Reconstruct the aliased image of the radiation information through an image reconstruction algorithm to obtain a two-dimensional radiation source distribution image.

Images