Spectral camera based on diffraction device group
By using diffraction device sets to diffraction modulation of the beam in the spectral camera, the shortcomings of existing spectral cameras in high-speed detection, stability and resolution are solved, and more efficient and stable spectral detection is achieved, and the equipment volume is reduced.
Patent Information
- Application Number
- CN202421222760.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-31
- Publication Date
- 2025-03-21
- Estimated Expiration
- 2034-05-31
AI Technical Summary
Existing spectral cameras have shortcomings in high-speed spectral detection, stability and resolution, and narrowband filter array spectral cameras take up a lot of space.
Using a spectral camera design based on a diffraction device group, the light beam is diffraction modulated by a diffraction device to generate first and second diffraction signals, and the wavelength distribution information and spatial distribution information are received and recorded through the image sensor module respectively.
Effectively separate and process the wavelength distribution information and spatial distribution information of the spectral image, improve the stability and detection accuracy of the spectral camera, while reducing the device volume and achieving a lighter design.
Smart Images
Figure CN222652378U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of optical equipment, in particular to a spectral camera based on a diffraction device group. Background Art
[0002] A spectral camera, also known as a spectral imaging spectrometer, is a detection device that integrates spectral acquisition and imaging. It can not only obtain the spatial distribution information of an object, but also synchronously obtain the spectral wavelength information of the object. It organically combines traditional two-dimensional imaging technology with spectral technology to obtain the spectral data cube of the object and analyze its characteristic properties. It is widely used in remote sensing monitoring, water quality measurement, agricultural planting, food safety testing and other fields.
[0003] Existing spectral cameras usually achieve light dispersion through a single filter or through multiple unique narrow-band filter arrays installed on respective detectors. Among them, spectral cameras based on a single narrow-band filter cannot achieve high-speed spectral detection and affect the stability and resolution of detection; while narrow-band filter arrays can measure multiple spectral components at the same time and achieve rapid detection of the spectrum, but it takes up a lot of space to a certain extent.
[0004] Therefore, it is urgent for those skilled in the art to provide a low-stray and lightweight spectral camera. Utility Model Content
[0005] The technical problem to be solved by the utility model is to overcome the defects in the prior art, thereby providing a spectral camera based on a diffraction device group.
[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:
[0007] A spectral camera based on a diffraction device group comprises a shell, an optical lens group, a diffraction device, an image sensor and a data processing device; the shell has a chamber and a light inlet connecting the chamber and a target space, and the optical lens group is located at the light inlet; the diffraction device is used to diffract and modulate the light beam input by the optical lens group to form a first diffraction signal beam and a second diffraction signal beam; the image sensor comprises a first image sensor module and a second image sensor module, the first image sensor module is used to receive the first diffraction signal beam and record the wavelength distribution information of the target spectral image, and the second image sensor module is used to receive the second diffraction signal beam and record the spatial distribution information of the target spectral image.
[0008] Preferably, the diffraction device includes a first diffraction device for shaping the wavefront of the light beam input by the optical lens group, and a second diffraction device for diffraction modulating the light beam input by the first diffraction device; the first diffraction device is located at the light entrance and on a side of the optical lens group close to the chamber.
[0009] Preferably, the first diffraction device and the second diffraction device are installed on the same optical path; and the second diffraction device and the first diffraction device are installed at a preset inclination angle.
[0010] Preferably, the first image sensor module and the second image sensor module may adopt one or more combinations of CMOS, CCD, and avalanche diode.
[0011] Preferably, the optical axis of the first image sensor module and the optical axis of the second diffraction device form a first preset angle; the optical axis of the second image sensor module and the optical axis of the second diffraction device form a second preset angle.
[0012] Preferably, the first diffraction device adopts a DOE composite device; and the second diffraction device adopts a planar reflective optical diffraction device.
[0013] Preferably, the data processing unit includes a computing unit, a storage unit and an output unit; the computing unit is electrically connected to the first image sensor module and the second image sensor module.
[0014] Preferably, the computing unit adopts one or a combination of CPU, NPU, GPU, FPGA, and DSP.
[0015] Compared with the prior art, the beneficial effects of the present invention are:
[0016] The spectral camera based on the diffraction device group provided in the above technical solution diffracts and modulates the light beam through the diffraction device, and generates a first diffraction signal and a second diffraction signal, and then receives the first diffraction signal and the second diffraction signal respectively through the first image sensor module and the second image sensor module, so as to obtain different types of information. On the one hand, it can effectively separate the two kinds of wavelength distribution information and spatial distribution information, increase the stability of the spectral camera, and make the spectral detection structure clearer and more accurate. On the other hand, the diffraction device can effectively separate the two kinds of information while effectively shortening the optical path, avoiding the influence of stray light on the detection results, and effectively reducing the volume of the spectral camera. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0018] Figure 1 This is a schematic structural diagram of the first embodiment of the utility model.
[0019] Figure 2 for Figure 1 Schematic cross-section diagram (top view).
[0020] Description of reference numerals:
[0021] 1. Shell; 11. Chamber; 12. Light entrance; 2. Optical lens group; 3. Diffraction device; 31. First diffraction device; 32. Second diffraction device; 4. Image sensor; 41. First image sensor module; 42. Second image sensor module; 5. Data processing device; 51. Calculation unit. DETAILED DESCRIPTION
[0022] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0023] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are 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 therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.
[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" 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 a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0025] See also Figure 1 and Figure 2 The embodiment of the utility model provides a spectral camera based on a diffraction device group, including a housing 1, an optical lens group 2, a diffraction device 3, an image sensor 4 and a data processing device 5.
[0026] Among them, the shell 1 has a chamber 11 and a light entrance 12 connecting the chamber 11 and the target space, and the optical lens group 2 is located at the light entrance 12; the diffraction device 3 is used to diffract and modulate the light beam input by the optical lens group 2 to form a first diffraction signal beam and a second diffraction signal beam; the image sensor 4 includes a first image sensor module 41 and a second image sensor module 42, the first image sensor module 41 is used to receive the first diffraction signal beam and record the wavelength distribution information of the target spectral image in the first diffraction signal beam, the second image sensor module 42 is used to receive the second diffraction signal beam and record the spatial distribution information of the target spectral image of the second diffraction signal beam, and the data processing device 5 is used to respectively process the wavelength distribution information recorded by the first image sensor module 41 and the spatial distribution information recorded by the second image sensor module 42, and then integrate them to form the original spectral image. It is worth noting that the “first image sensor module 41 is used to receive the first diffraction signal beam and record the wavelength distribution information of the target spectral image in the first diffraction signal beam” referred to here does not limit the first image sensor module 41 to only being able to receive the first diffraction signal beam and record the wavelength distribution information of the target spectral image in the first diffraction signal beam, but can also receive the spatial distribution information of the first diffraction signal beam, but it is more focused on receiving the first diffraction signal beam and recording the wavelength distribution information of the target spectral image in the first diffraction signal beam. Similarly, “the second image sensor module 42 is used to receive the second diffraction signal beam and record the spatial distribution information of the target spectral image of the second diffraction signal beam” does not limit it to only being able to receive the second diffraction signal beam and record the spatial distribution information of the target spectral image of the second diffraction signal beam, but it is more focused on receiving the second diffraction signal beam and recording the spatial distribution information of the target spectral image of the second diffraction signal beam.
[0027] In this embodiment, the light beam is diffracted and modulated by the diffraction device 3, and a first diffraction signal and a second diffraction signal are generated. The first diffraction signal and the second diffraction signal are received respectively by the first image sensor module 41 and the second image sensor module 42, so as to obtain different types of information. On the one hand, the wavelength distribution information of the target spectral image and the spatial distribution information of the target spectral image can be effectively processed separately, thereby increasing the stability of the spectral camera and making the spectral detection structure clearer and more accurate. On the other hand, the diffraction device 3 can effectively separate the two types of information while effectively shortening the optical path, thereby avoiding the influence of stray light on the detection results, and can further improve the detection accuracy while effectively reducing the volume of the spectral camera, making the camera lighter.
[0028] The structure, size, material, etc. of the shell 1 can be set according to actual use requirements, which can realize the installation of various structures and provide a light-proof environment for spectral detection to eliminate the influence of external ambient light sources on the test samples.
[0029] See also Figure 2 In this embodiment, the optical lens group 2 is located at the light entrance 12, the diffraction device 3, the image sensor 4 and the computing unit 51 of the data processing device 5 are all arranged in the chamber 11, and the light entrance 12 is used to input the light beam, thereby realizing the input of the light beam and the installation of each structure, and providing a light-proof environment for the spectrometer detection through the housing 1 that is closed to a certain extent, so as to eliminate the influence of the external ambient light source on the test sample. Of course, in order to realize the electrical connection between the various structures, a data connection port can also be opened on the housing 1 according to the needs.
[0030] Furthermore, the housing 1 is configured as a rectangular parallelepiped or cubic structure, and the side length of the housing 1 can be set in the range of 20 mm to 180 mm, for example, 20 mm, 100 mm or 180 mm; the light inlet 12 is configured as a rectangle, and its size can also be set according to requirements, and the side length of the light inlet 12 can be set in the range of 1 mm to 50 mm, for example, 1 mm, 25.5 mm or 50 mm. The housing 1 can be made of metal or high molecular polymer material to provide a light-proof environment for spectral detection and analysis.
[0031] See also Figure 2The diffraction device 3 includes a first diffraction device 31 and a second diffraction device 32. The first diffraction device 31 is located at the light inlet 12 and on the side of the optical lens group 2 close to the chamber 11. The first diffraction device 31 is used to shape the light wave front of the light beam input by the optical lens group 2, so that the light beam can be evenly irradiated on the second diffraction device 32, and at the same time, it can filter out the stray light outside the detection range to avoid its influence on the detection accuracy and results. The second diffraction device 32 is used to diffract and modulate the light beam input by the first diffraction device 31, which is specifically divided into a first modulation signal and a second modulation signal. The first modulation signal is to perform a first mode phase correction on the light beams of different wavelengths in the shaped complex light, so that the light of different wavelengths is coded and propagated in space. The second modulation signal is a signal of a second mode phase correction after the incident light passes through the second diffraction device 32, and its spatial distribution information is retained, thereby forming a first diffraction signal beam and a second diffraction signal beam respectively.
[0032] Specifically, in this embodiment, the size of the optical lens group 2 (specifically, the length, width and height of the optical lens group 2) ranges from 1 to 80 mm, and is located on the side of the first diffraction device 31 away from the chamber 11, so that the optical lens group 2 can cooperate with the first diffraction device 31 to adjust the distance between the target object and the spectral system and control the system field of view. It is worth noting that the lens type and focal length of the optical lens group 2 can be selected and replaced according to the required field of view and the position of the target object to be measured.
[0033] Furthermore, the first diffraction device 31 adopts a DOE composite device, and the first diffraction device 31 and the second diffraction device 32 are installed on the same optical path; the second diffraction device 32 and the first diffraction device 31 are installed at a preset tilt angle. Through this solution, it is possible to avoid the central light intensity being high and the edge light intensity being weak when the light beam is incident on the second diffraction device 32, thereby providing a uniform incident light source to the second diffraction device 32, improving the diffraction efficiency of the second diffraction device 32, and limiting the light incident at a certain angle, avoiding the influence of stray light. It is worth noting that the "preset installation tilt angle" referred to here is the angle A between the incident plane of the first diffraction device 31 and the incident plane of the second diffraction device 32, and the value range of the angle A is 10° to 80°.
[0034] Furthermore, in order to increase the diffraction efficiency and facilitate the installation and adjustment of the second diffraction device 32, in the present embodiment, the second diffraction device 32 adopts a planar reflective optical diffraction device. The setting of the reflective optical diffraction device can greatly reduce the overall volume, making the entire spectral camera compact and portable, and at the same time, can also improve the resolution of the spectral camera.
[0035] Of course, in other embodiments, the second diffraction element 32 may also adopt a transmissive DOE. In this embodiment, it is necessary to additionally process the reflected signal and the stray light caused therein, and the positions of the first image sensor module 41 and the second image sensor module 42 need to be adjusted to the corresponding transmissive receiving positions, such as being set on both sides of the diffraction element 32, and can be adjusted according to actual needs. Compared with this embodiment, the second diffraction element 32 adopts a transmissive DOE, which is slightly more technically difficult than a reflective DOE, and it is necessary to add other components to process the reflected signal and the stray light caused therein.
[0036] In addition, a polarization elimination plate may be selectively placed on the optical path in front of the first diffraction device 31 and the second diffraction device 32 to facilitate the measurement of objects with obvious polarization, such as displays.
[0037] The installation methods of the second diffraction device 32, the first image sensor module 41 and the second image sensor module 42 can be set in various ways, which can be specifically set according to actual usage requirements, so that the first image sensor module 41 can receive the first diffraction signal beam and record the wavelength distribution information of the target spectral image, and the second image sensor module 42 can receive the second diffraction signal beam and record the spatial distribution information of the target spectral image.
[0038] In this embodiment, the optical axis of the first image sensor module 41 and the optical axis of the second diffraction device 32 form a first preset angle; the optical axis of the second image sensor module 42 and the optical axis of the second diffraction device 32 form a second preset angle. Figure 2 , the optical axis L1 of the first image sensor module 41 and the optical axis L of the second diffraction device 32 form a first preset angle B, B is 0°, and of course, the value range of the first preset angle B satisfies -60° to 60°. The optical axis L2 of the second image sensor module 42 and the optical axis L of the second diffraction device 32 form a second preset angle C, and in this embodiment, C is set to 60°. Of course, the value range of the second preset angle C satisfies 10° to 90°. It is worth noting that, for the convenience of explanation, in this embodiment, the optical axis L of the second diffraction device 32 is taken as the initial position. At this time, the angle generated by counterclockwise rotation is a positive angle, and the angle generated by clockwise rotation is a negative angle.
[0039] Furthermore, the first image sensor module 41 and the second image sensor module 42 both use complementary metal oxide semiconductor area array image sensors (CMOS), and their related parameters meet the following requirements: field of view angle of 40-150°, focal length of 1-5 mm, and effective pixel array of 1-5000H×1-5000V. Of course, in other embodiments, the first image sensor module 41 and the second image sensor module 42 (their photosensitive elements) may also use CCD, avalanche diodes, etc.
[0040] Among them, the first image sensor module 41 is used to receive the first diffraction signal light beam, and convert the received spectral energy into an easily measurable electrical signal, and measure the wavelength and intensity of the corresponding spectral component; the second image sensor module 42 is used to receive the second diffraction signal light beam, and convert the received spectral energy into an easily measurable electrical signal, and measure the spatial distribution information of the corresponding spectral component.
[0041] Specifically, in one embodiment, the first image sensor module 41 includes an aperture stop, a lens group and a CMOS photosensitive bottom surface; the second image sensor module 42 includes an aperture stop, a lens group and a CMOS photosensitive bottom surface. Among them, taking the first image sensor module 41 as an example, the aperture stop is located on the side close to the second diffraction device 32, and the diameter can be set to 0.22-22mm, and the thickness can be ignored. By reasonably setting the diameter of the aperture stop, the spectral resolution of the entire system can be improved. The lens group is located between the aperture stop and the CMOS photosensitive bottom surface, with a diameter of 0.3-5mm and a focal length of 0.6-6mm. Of course, in other embodiments, the second image sensor module 42 can also be composed of CMOS without an aperture stop and a lens group. It is worth noting that when the first sensor module 41 is equipped with an aperture stop and a lens, the first diffraction element 31 can also be cancelled.
[0042] In addition, the image sensor 4 is preferably a mono (monochrome) CFA (color fiter array), of course, other forms of CFA are also applicable and can be selected according to actual conditions.
[0043] See also Figure 1 and Figure 2 The data processing device 5 includes a computing unit 51 , a storage unit and an output unit; the computing unit 51 is electrically connected to the first image sensor module 41 and the second image sensor module 42 .
[0044] Specifically, the calculation unit 51 is used to store the signals measured by the first image sensor module 41 and the second image sensor module 42 after preliminary processing, and transmit them to the output unit through the data transmission line to further display and process the detected spectral characteristics, and then obtain the complete spectral characteristics of the target object by combining the signal measured by the first image sensor module 41 with the signal measured by the first image sensor module 42.
[0045] Furthermore, the computing unit 51 uses one or a combination of CPU, NPU, GPU, FPGA, and DSP to perform gradient calculations, matrix calculations, convolution operations, Fourier transforms, neural network activation operations, etc. The number of floating-point operations of the computing unit is set to be selected between 10GFLOPs and 80TFLOPs to meet the requirements of different CMOS resolutions, output frame rates, and spectral resolution combinations.
[0046] It is worth noting that a unique fusion algorithm is used in the computing unit 51, and a complete inversion algorithm from the modulated signal to the spectral cube is obtained by adding prior optical information, and the three-dimensional spectral imaging data is inverted by a two-dimensional image sensor, which can be obtained without the use of time multiplexing and space multiplexing, thus avoiding the waste of time and saving spatial pixels. In addition, it can be implemented in an embedded low-power processor in a spectral camera with low computing power (such as 10G-3TFLOPs), without the need for communication and cloud computing equipment, to reduce costs.
[0047] The present invention also provides an operating method based on the above-mentioned spectral camera, which specifically includes the following steps:
[0048] The target spectral image information in the target space enters the system through the light inlet 12 of the spectral camera housing 1 and passes through the optical lens group 2;
[0049] The diffraction device 3 is used to diffract and modulate the light beam input by the optical lens group 2 to form a first diffraction signal light beam and a second diffraction signal light beam;
[0050] Using the first image sensor module 41 of the image sensor 4 to receive the first diffraction signal beam and record the wavelength distribution information of the target spectrum image;
[0051] The second image sensor module 42 of the image sensor 4 is used to receive the second diffraction signal beam and record the spatial distribution information of the target spectrum image.
[0052] The diffraction device 3 is used to diffract and modulate the light beam input by the optical lens group 2 to form a first diffraction signal light beam and a second diffraction signal light beam, which specifically includes:
[0053] The first diffraction device 31 of the diffraction device 3 is used to perform wavefront shaping on the light beam input by the optical lens group 2;
[0054] The second diffraction element 32 of the diffraction device 3 is used to diffract and modulate the light wave input from the first diffraction element 31 .
[0055] The above-mentioned implementation modes are only preferred implementation modes of the present invention, and cannot be used to limit the protection scope of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.
Claims
1. A spectral camera based on a diffraction device group, characterized in that: It includes a housing, an optical lens group, a diffraction device, an image sensor and a data processing device; The housing has a chamber and a light inlet connecting the chamber and the target space, and the optical lens group is located at the light inlet; The diffraction device is used to diffract and modulate the light beam input by the optical lens group to form at least a first diffraction signal light beam and a second diffraction signal light beam; The image sensor includes a first image sensor module and a second image sensor module. The first image sensor module is used to receive the first diffraction signal beam and record the wavelength distribution information of the target spectral image. The second image sensor module is used to receive the second diffraction signal beam and record the spatial distribution information of the target spectral image.
2. A spectral camera based on a diffraction device group according to claim 1, characterized in that: The diffraction device comprises a first diffraction device for shaping the wavefront of the light beam input from the optical lens group, and a second diffraction device for diffraction modulation of the light beam input from the first diffraction device; The first diffraction device is located at the light entrance and on a side of the optical lens group close to the chamber.
3. The spectral camera based on a diffraction device group according to claim 2, characterized in that: The first diffraction device and the second diffraction device are installed on the same optical path; The second diffraction component and the first diffraction component are installed at a preset inclination angle.
4. The spectral camera based on a diffraction device group according to claim 2, characterized in that: The first image sensor module and the second image sensor module may adopt one or more combinations of CMOS, CCD, and avalanche diode.
5. The spectral camera based on a diffraction device group according to claim 4, characterized in that: The optical axis of the first image sensor module and the optical axis of the second diffraction element form a first preset angle; The optical axis of the second image sensor module and the optical axis of the second diffraction element form a second preset angle.
6. The spectral camera based on a diffraction device group according to claim 2, characterized in that: The first diffraction device adopts a DOE composite device; The second diffraction device is a plane reflective optical diffraction device.
7. The spectral camera based on a diffraction device group according to claim 1, characterized in that: The data processing device includes a computing unit, a storage unit and an output unit; The computing unit is electrically connected to the first image sensor module and the second image sensor module.
8. The spectral camera based on a diffraction device group according to claim 7, characterized in that: The computing unit adopts one or a combination of CPU, NPU, GPU, FPGA, and DSP.