Miniature snapshot type hyperspectral imager based on angle characteristics

Abstract

The invention relates to a miniature snapshot-type hyperspectral imager based on angle characteristics, and belongs to the technical field of spectral imaging, the miniature snapshot-type hyperspectral imager comprises an imaging lens, a light filter group and a photosensitive component, the light filter group comprises at least two groups of light filters, and the transmission spectrums among the groups of light filters under incident light of different angles are similar. Incident light at different angles passes through the imaging lens, is gathered through the light filter and is imaged on the photosensitive component. The miniature snapshot type hyperspectral imager provided by the invention has the advantages of extremely small size, extremely small power consumption and extremely low cost.

Description

Technical Field

[0001] The invention belongs to the field of spectral imaging, and in particular relates to a miniature snapshot type hyperspectral imager based on angle characteristics. Background Art

[0002] Traditional hyperspectral imagers are expensive, bulky, and have limited application scenarios. In recent years, miniature snapshot hyperspectral imagers based on filter array structures have developed rapidly with their advantages of low cost and small size. However, they are usually sensitive to the incident angle of the light source, and the transmission spectra formed by different incident angles of the same structure vary greatly.

[0003] At present, the solution to this problem basically adopts a small incident angle or customizes a specific algorithm correction solution for different incident angle areas, which will sacrifice a large field of view or increase the difficulty of spectral calculation calibration and image signal processing (ISP). Summary of the invention

[0004] The present application provides a miniature snapshot hyperspectral imager based on angle characteristics to at least solve the above technical problems existing in the prior art.

[0005] An embodiment of the present application provides a miniature snapshot hyperspectral imager based on angle characteristics, including an imaging lens, a filter group and a photosensitive component, the filter group includes at least two groups of filters, and the transmission spectra between the groups of filters under incident light at different angles are similar; incident light at different angles passes through the imaging lens, passes through the filter set, and is imaged on the photosensitive component.

[0006] In one possible implementation, the optical filter group is composed of a plurality of groups of micro-nano structures or thin films with adjustable refractive index.

[0007] In one embodiment, the film is one layer or multiple layers.

[0008] In one embodiment, any of the filters is within the incident angle range ( θ i - Δ φ i ~ θ i + Δ φ i * ) transmission is similar.

[0009] In one possible implementation, a reading circuit is also included, and the photosensitive component converts the light signal transmitted through the filter group into an electrical signal. The electrical signal collected on the photosensitive component is read and processed by the reading circuit, and finally the output is converted into a spectral signal.

[0010] In one possible implementation manner, the photosensitive component is a CMOS image sensor.

[0011] In one embodiment, the focal length and aperture of the imaging lens can be designed and adjusted according to the application scenario.

[0012] Compared with the prior art, this application has the following advantages: 1. The miniature snapshot hyperspectral imager of the present application has extremely small size and power consumption, and extremely low cost; 2. This application can be adapted to the rapid typesetting of different optical systems according to application scenarios; 3. This application can simplify the spectral calibration algorithm of the hyperspectral imaging system and reduce the complexity of ISP. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic diagram of the structure of a miniature snapshot hyperspectral imager in an embodiment of the present application; Figure 2 : is the transmission spectrum diagram of the three groups of filters at different angles in the embodiment of the present application; Figure 3 Schematic diagrams of three arrangements of micro-nano structures in the optical filter of the embodiment of the present application; Figure 4 is a schematic diagram of layout rules of the filter group based on imaging angle in an embodiment of the present application; Description of reference numerals: 1. Imaging lens; 2. Filter group; 3. Photosensitive components. DETAILED DESCRIPTION

[0014] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0015] In the description of the present application, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application. Reference Figure 1 The present application discloses a miniature snapshot hyperspectral imager based on angle characteristics, including an imaging lens 1, a filter group 2 and a photosensitive component 3, wherein the focal length and aperture of the imaging lens 1 can be designed and adjusted according to the application scenario.

[0016] Filter set 2 is a set of specific filters made of micro-nano structures with the same transmission spectrum for different incident angles. Specifically, it is composed of multiple sets of micro-nano structures or thin films with adjustable refractive index, and the thin films are one or more layers. The wavelength changes of light at different incident angles in filter set 2 are as follows: Figure 2 As shown, the projection spectra of three of the selected structures are shown.

[0017] The filter group 2 includes at least two groups of filters, and the transmission spectra of the filters under different incident angles are similar. The incident light at different angles passes through the imaging lens 1, the filter set, and is imaged on the photosensitive component 3. Furthermore, since the incident angles of the light when it is focused on the surface of the photosensitive component are different, any filter needs to be within the incident angle range ( θ i - Δ φ i ~ θ i + Δ φ i * ) transmission spectra are similar.

[0018] Figure 3 Several types of applications are listed in the table below: θ 0 ,θ 1 ,θ 2 ) Micro-nano structures with similar transmission spectra can modulate light at different incident angles through different shapes, periods, etc. to make the transmitted spectra basically consistent.

[0019] based on Figure 3 The design structure arranges them on the photosensitive components according to the imaging angle, such as Figure 4 As shown, the designed filter combination can be quickly layout and photosensitive component packaging in different angle areas.

[0020] The miniature snapshot hyperspectral imager also includes a reading circuit. The photosensitive component 3 converts the light signal transmitted through the filter group 2 into an electrical signal. The electrical signal collected on the photosensitive component 3 is read and processed by the reading circuit, and finally a spectral signal is output.

[0021] Furthermore, the photosensitive component is a CMOS image sensor.

[0022] This application obtains a filter combination with the same optical transmission matrix (a collection of projected spectra) at any light incident angle through optical design and process processing (such as semiconductor micro-nano preparation), thereby realizing the rapid arrangement and design of the filter array of the micro-hyperspectral imager, and realizing a snapshot-type micro-hyperspectral imager with a large field of view and high performance through the co-packaging integration of the same detector array (such as image sensor) and the reading circuit. That is, for any application scenario and optical system, by constructing a filter combination with a specific optical transmission matrix of multiple groups of micro-nano structures or refractive index adjustable thin films or multilayer films in the same plane, the filter combination in the optical path has the same or similar optical transmission matrix for each incident light angle.

[0023] For different chief ray angles (CRA) in the optical path, the filter combinations with the same or similar optical transmission matrix are arranged according to the corresponding CRA. At the same time, the optical signal passing through the filter array is converted into an electrical signal on the detector array, and the electrical signal collected by the detector array is processed and converted into spectral information through a reading circuit or an external processing circuit. At the same time, the semiconductor process is used to precisely process the packaging module, and the packaging realizes a miniature snapshot hyperspectral imager.

[0024] The miniature snapshot hyperspectral imager of the present application has an extremely small size and power consumption, and through a plurality of filter sets designed for the incident angle, it can adapt to the application scenarios and the rapid layout of different optical systems while simplifying the spectral calibration algorithm and reducing the complexity of ISP.

[0025] The above are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A miniature snapshot hyperspectral imager based on angle characteristics, characterized in that: It includes an imaging lens, a filter group and a photosensitive component. The filter group includes at least two groups of filters, and the transmission spectra of each group of filters are similar under incident light at different angles. The incident light at different angles passes through the imaging lens, the filter group, and is imaged on the photosensitive component.

2. The miniature snapshot hyperspectral imager based on angle characteristics according to claim 1, characterized in that: The optical filter group is composed of multiple groups of micro-nano structures or thin films with adjustable refractive index.

3. The miniature snapshot hyperspectral imager based on angle characteristics according to claim 2, characterized in that: The film is one layer or multiple layers.

4. The miniature snapshot hyperspectral imager based on angle characteristics according to claim 1, characterized in that: Any of the filters is within the incident angle range ( θ i - Δ φ i ~ θ i + Δ φ i * ) transmission is similar.

5. The miniature snapshot hyperspectral imager based on angle characteristics according to claim 1, characterized in that: It also includes a reading circuit, and the photosensitive component converts the light signal transmitted through the filter group into an electrical signal. The electrical signal collected on the photosensitive component is read and processed by the reading circuit, and finally the output is converted into a spectral signal.

6. The miniature snapshot hyperspectral imager based on angle characteristics according to claim 5, characterized in that: The photosensitive component is a CMOS image sensor.

7. The miniature snapshot hyperspectral imager based on angle characteristics according to claim 1, characterized in that: The focal length and aperture of the imaging lens can be designed and adjusted according to the application scenario.

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