Calibration device and calibration method of imaging spectrometer

Abstract

The invention discloses a calibration device and a calibration method of an imaging spectrometer. The calibration device comprises a light source group which comprises a spectral line light source, a wide-spectrum light source and a switching mechanism; the integrating sphere is used for receiving the first incident light emitted by the spectral line light source and the second incident light emitted by the wide-spectrum light source in a time-sharing manner so as to respectively form a first Lambert light source and a second Lambert light source in corresponding wavelength ranges at a light outlet of the integrating sphere and enable an imaging spectrometer to be calibrated to obtain a corresponding first spectral image and a corresponding second spectral image; and the controller is used for calibrating the imaging spectrometer according to the first spectral image and the second spectral image. The calibration device can meet the calibration requirements of multiple parameters in the imaging spectrometer at the same time, it is guaranteed that uniform, stable and intensity-adjustable spectrums and radiance can be output on the light emitting face of the calibration device, meanwhile, crosstalk among physical quantities of multiple dimensions can be avoided, and therefore the measurement level of the whole calibration device is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical testing equipment, and particularly relates to a calibration device for an imaging spectrometer, a calibration method for an imaging spectrometer, and a computer-readable storage medium. Background Art

[0002] With the rapid development of hyperspectral imaging technology and the rapid growth of its application scenarios, there are various designs and packaging styles for imaging spectrometers. It is difficult to design a set of typical parameters or styles that can meet all potential future uses, which will inevitably lead to large differences in the performance indicators of different imaging spectrometers. Therefore, developing a calibration device for imaging spectrometers is of great significance for standardizing the development and application of imaging spectrometers.

[0003] The principle of spectral measurement technology is to analyze by measuring the self-luminescence of an object or the reflected light of its interaction with a light source. Traditional spectral measurement technology, from the spatial dimension, is for one-dimensional single-point targets and uses traditional spectrometers. Spectral imaging technology combines spectral measurement and imaging technology, combines the spectral and image resolution capabilities, and from the spatial dimension, is for two-dimensional planar targets and uses a new type of imaging spectrometer.

[0004] Taking smile and keystone distortions as examples, they are two optical aberrations that will seriously affect the performance indicators of imaging spectrometers but do not exist in traditional spectrometers. Smile distortion is a spectral distortion mainly originating from a dispersive imaging system, while keystone distortion is a spatial distortion mainly originating from a front imaging system. Therefore, the calibration device for traditional spectrometers is no longer applicable to calibrate new imaging spectrometers, and the calibration requirements for imaging spectrometers widely come from multiple industries such as medical and health, food safety, environmental monitoring, industrial inspection, and national defense security.

[0005] In response to this, based on the working principle of spectral imaging equipment, there is currently the use of an integrating sphere type uniform surface light source as a Lambertian spatial and angular spectral radiation field to calibrate imaging spectrometers. However, the structure and function of the existing integrating sphere type uniform surface light source are relatively single and cannot simultaneously meet the calibration requirements of parameters such as wavelength accuracy, spectral radiance, and response linearity of imaging spectrometers.

[0006] In order to solve the above problems existing in the prior art, there is an urgent need in the art for a calibration technology that matches imaging spectrometers, which can simultaneously meet the calibration requirements for multiple parameters in imaging spectrometers, ensure that a uniform, stable, and intensity-adjustable spectrum and radiance can be output on its light exit surface, and at the same time, can avoid crosstalk between physical quantities in multiple dimensions, thereby improving the measurement level of the entire calibration device. Summary of the Invention

[0007] A brief overview of one or more aspects is given below to provide a basic understanding of these aspects. This overview is not an exhaustive survey of all contemplated aspects and is neither intended to identify key or decisive elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that follows.

[0008] In order to overcome the above-mentioned defects existing in the prior art, the present invention provides a calibration device for an imaging spectrometer, a calibration method for an imaging spectrometer, and a computer-readable storage medium, which can simultaneously meet the calibration requirements for multiple parameters in the imaging spectrometer, ensure that a uniform, stable, and intensity-adjustable spectrum and radiance can be output on its light exit surface, and at the same time, can avoid crosstalk between physical quantities in multiple dimensions, thereby improving the measurement level of the entire calibration device.

[0009] Specifically, the calibration device for an imaging spectrometer provided according to the first aspect of the present invention includes: a light source group, including a spectral line light source, a broadband light source, and a switching mechanism; an integrating sphere for receiving the first incident light emitted by the spectral line light source and the second incident light emitted by the broadband light source in a time-sharing manner to respectively form a first Lambertian light source and a second Lambertian light source with corresponding wavelength ranges at its light exit port, and enabling the imaging spectrometer to be calibrated to obtain corresponding first spectral images and second spectral images; and a controller configured to: calibrate the imaging spectrometer according to the first spectral image and the second spectral image.

[0010] In addition, the calibration method for an imaging spectrometer provided according to the second aspect of the present invention includes the following steps: switching the spectral line light source of the calibration device provided in the first aspect of the present invention to the light inlet of its integrating sphere to form a first Lambertian light source with a corresponding wavelength range at the light exit port of the integrating sphere, and enabling the imaging spectrometer to be calibrated to obtain a corresponding first spectral image; switching the broadband light source of the calibration device to the light inlet of the integrating sphere to form a second Lambertian light source with a corresponding wavelength range at the light exit port of the integrating sphere, and enabling the imaging spectrometer to obtain a corresponding second spectral image; and calibrating the imaging spectrometer according to the first spectral image and the second spectral image.

[0011] In addition, according to the third aspect of the present invention, there is also provided a computer-readable storage medium, on which computer instructions are stored. When the computer instructions are executed by a processor, the calibration method for an imaging spectrometer provided in the second aspect of the present invention is implemented. Description of the Drawings

[0012] After reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings, the above features and advantages of the present invention can be better understood. In the drawings, the components are not necessarily drawn to scale, and components having similar relevant characteristics or features may have the same or similar reference numerals.

[0013] Figure 1 The structural schematic diagram of a calibration device for an imaging spectrometer provided according to some embodiments of the present invention is shown;

[0014] Figure 2A The front structural schematic diagram of an integrating sphere provided according to some embodiments of the present invention is shown;

[0015] Figure 2B is Figure 2A The side structural schematic diagram of the integrating sphere shown;

[0016] Figure 3 The curve graph of the spectral reflectivity of PTFE provided according to some embodiments of the present invention is shown;

[0017] Figure 4 The structural schematic diagram of a spectral line light source provided according to some embodiments of the present invention is shown;

[0018] Figure 5A The spectral power distribution of a laser plasma light source provided according to some embodiments of the present invention is shown;

[0019] Figure 5B The spectral power distribution of a quartz halogen tungsten lamp provided according to some embodiments of the present invention is shown;

[0020] Figure 5C The structural schematic diagram of an optical reflection structure supporting a quartz halogen tungsten lamp provided according to some embodiments of the present invention is shown;

[0021] Figure 6 The hybrid spectrogram of a laser plasma light source (PEL) and a quartz halogen tungsten lamp (QTH) provided according to some embodiments of the present invention is shown;

[0022] Figure 7 The curve graph of the spectral response range and photoelectric sensitivity of a silicon photodiode provided according to some embodiments of the present invention is shown;

[0023] Figure 8A The spectral schematic diagram of non-distorted crosstalk provided according to some embodiments of the present invention is shown;

[0024] Figure 8B The spectral schematic diagram of the presence of smile distortion crosstalk provided according to some embodiments of the present invention is shown;

[0025] Figure 8C Shows a spectrogram with trapezoidal distortion crosstalk provided according to some embodiments of the present invention;

[0026] Figure 9A Shows a schematic structural diagram of a checkerboard target board provided according to some embodiments of the present invention;

[0027] Figure 9B Shows a schematic structural diagram of a slit target board provided according to some embodiments of the present invention;

[0028] Figure 9C Shows a schematic structural diagram of a pinhole target board provided according to some embodiments of the present invention;

[0029] Figure 10 Shows a flowchart of a calibration method for an imaging spectrometer provided according to some embodiments of the present invention;

[0030] Figure 11 Shows a calibration flowchart for a staring imaging spectrometer provided according to some embodiments of the present invention; and

[0031] Figure 12 Shows a calibration flowchart for a pushbroom imaging spectrometer provided according to some embodiments of the present invention.

[0032] Reference numerals:

[0033] 100 Calibration device;

[0034] 110 Spectral line light source;

[0035] 111 Semiconductor laser;

[0036] 112 Switching mechanism;

[0037] 120 Integrating sphere;

[0038] 121 Light output port;

[0039] 122, 123, 124 Light input ports;

[0040] 125 Detection element interface;

[0041] 130 Broadband light source;

[0042] 131 Laser plasma light source;

[0043] 132 Quartz halogen tungsten lamp;

[0044] 133, 134 Variable aperture;

[0045] 510 Optical reflection structure;

[0046] 910 checkerboard target board;

[0047] 920 slit target board;

[0048] 921 slit;

[0049] 930 pinhole target board;

[0050] 931 pinhole;

[0051] Steps S11 to S13; and

[0052] Steps S131 to S135. Detailed implementation manners

[0053] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiments, this does not mean that the features of this invention are limited to this implementation manner. On the contrary, the purpose of introducing the invention in conjunction with the implementation manner is to cover other alternatives or modifications that may be extended based on the claims of the present invention. In order to provide a deep understanding of the present invention, many specific details will be included in the following description. The present invention can also be implemented without using these details. In addition, in order to avoid confusing or obscuring the key points of the present invention, some specific details will be omitted in the description.

[0054] 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0055] In addition, the "upper", "lower", "left", "right", "top", "bottom", "horizontal", and "vertical" used in the following description should be understood as the orientations shown in this section and the related drawings. This relative term is only for the convenience of description and does not represent that the device described needs to be manufactured or operated in a specific orientation, so it should not be understood as a limitation to the present invention.

[0056] It is understood that although terms such as "first", "second", "third", etc. may be used herein to describe various components, regions, layers, and / or parts, these components, regions, layers, and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers, and / or parts. Therefore, the first component, region, layer, and / or part discussed below may be referred to as the second component, region, layer, and / or part without departing from some embodiments of the present invention.

[0057] As described above, the calibration device for traditional spectrometers is no longer suitable for calibrating new imaging spectrometers. In this regard, based on the working principle of spectral imaging devices, there is currently a method of using an integrating sphere type uniform surface light source as a Lambertian spatial and angular spectral radiation field to calibrate imaging spectrometers. However, the existing integrating sphere type uniform surface light source has a relatively single structure and function, and cannot simultaneously meet the calibration requirements of parameters such as wavelength accuracy, spectral radiance, and response linearity of imaging spectrometers.

[0058] To solve the above problems existing in the prior art, the present invention provides a calibration device for an imaging spectrometer, a calibration method for an imaging spectrometer, and a computer-readable storage medium, which can simultaneously meet the calibration requirements for multiple parameters in an imaging spectrometer, ensure that a uniform, stable, and intensity-adjustable spectrum and radiance can be output on its light-emitting surface, and at the same time, can also avoid crosstalk between physical quantities in multiple dimensions, thereby improving the measurement level of the entire calibration device.

[0059] In some non-limiting embodiments, the calibration device for an imaging spectrometer provided in the first aspect of the present invention can be used to implement the calibration device method for an imaging spectrometer provided in the second aspect of the present invention.

[0060] Specifically, in some non-limiting embodiments, the computer-readable storage medium provided in the third aspect of the present invention stores computer instructions. When the computer instructions are executed by a processor, they can be used to implement the calibration method for an imaging spectrometer provided in the second aspect of the present invention.

[0061] The working principle of the above calibration device for an imaging spectrometer will be described below in conjunction with some embodiments of the calibration method for an imaging spectrometer. Those skilled in the art can understand that these embodiments of the calibration method for an imaging spectrometer are only some non-limiting implementation manners provided by the present invention, aiming to clearly show the main concept of the present invention and provide some specific solutions convenient for the public to implement, rather than being used to limit all working modes or all functions of the calibration device for an imaging spectrometer. Similarly, the calibration device for an imaging spectrometer is also only a non-limiting implementation manner provided by the present invention, and does not limit the implementation subject of each step in these calibration device methods for an imaging spectrometer.

[0062] Please refer to Figure 1 , Figure 1 which shows a schematic structural diagram of a calibration device for an imaging spectrometer provided according to some embodiments of the present invention.

[0063] As Figure 1 shown, in some embodiments of the present invention, the calibration device for an imaging spectrometer may mainly include a light source group, an integrating sphere 120, and a controller (not shown in the drawings). The light source group may include a spectral line light source 110 and its switching mechanism 112, and a broadband light source 130. The integrating sphere 120 may be configured to receive the first incident light emitted by the spectral line light source 110 and the second incident light emitted by the broadband light source 130 at different times, so as to respectively form a first Lambertian light source and a second Lambertian light source with corresponding wavelength ranges at its light outlet 121, and enable the imaging spectrometer to be calibrated to obtain corresponding first spectral images and second spectral images. The controller may be configured to: calibrate the imaging spectrometer according to the first spectral image and the second spectral image.

[0064] Specifically, please refer to Figure 2A and Figure 2B , Figure 2A which shows a schematic front view of an integrating sphere provided according to some embodiments of the present invention, Figure 2B and Figure 2A is a schematic side view of the integrating sphere shown in

[0065] Combined with Figure 1 , Figure 2A and Figure 2B shown, in some embodiments, an integrating sphere type uniform surface light source may be used as a Lambertian space and angular spectral radiation field to calibrate the imaging spectrometer. Since the imaging spectrometer usually uses a C-mount lens, its light passing aperture is generally less than 60 mm. In this embodiment, the diameter of the integrating sphere 120 may be 300 mm, and it includes two light inlet ports, namely the light inlet port 122 of the spectral line light source 110 for receiving the first incident light, and the light inlet ports 123 and 124 of the broadband light source 130 for receiving the second incident light. Optionally, the diameters of the two light inlet ports 122, and 123 and 124 may be 25.4 mm, and the diameter of the light outlet 121 of the integrating sphere 120 may be 100 mm.

[0066] Furthermore, in some embodiments, the interior of the integrating sphere 120 may be coated with a high-reflectivity diffuse reflection material. Specifically, the reflection material may be selected as polytetrafluoroethylene (PTFE). PTFE has a high reflectivity in the ultraviolet, visible, and near-infrared wavelength ranges. As Figure 3 shown, PTFE has good Lambertian reflection characteristics in the visible-near infrared wavelength range of 400 nm to 1000 nm.

[0067] In addition, in some alternative embodiments, a baffle (not shown in the drawings) may be provided between the light inlet and the light outlet 121 inside the integrating sphere 120. By reasonably arranging the position of the light outlet 121 outside the integrating sphere 120 to match the size of the baffle inside the integrating sphere 120, it is possible to ensure that a uniform first Lambertian light source or second Lambertian light source is formed at the light outlet 121 of the integrating sphere 120. In some preferred embodiments, with a suitable baffle size, the uniformity at the light outlet 121 can reach more than 98%.

[0068] In this embodiment, compared with the traditional spectral radiation standard lamp paired with a diffuse reflection target board, the integrating sphere type uniform surface light source in the present invention has significant advantages in terms of light output uniformity, stability, light output surface size, field of view angle, intensity adjustment, spectral mixing, etc.

[0069] Further, please refer to Figure 4 , Figure 4 which shows a schematic structural diagram of a spectral line light source provided according to some embodiments of the present invention.

[0070] In the prior art, a commonly used mercury-argon lamp is used as a spectral line light source to calibrate the wavelength of a traditional spectrometer, and its characteristic spectral lines can cover a wavelength range of about 254 - 922 nm. However, since the output power of the mercury-argon lamp is small, it is not sufficient to be introduced into the integrating sphere 120 to calibrate the wavelength accuracy of the imaging spectrometer. In view of this, in some embodiments of the present invention, a semiconductor laser 111 can be selected as the spectral line light source 110 to provide a monochromatic light source for calibrating the imaging spectrometer.

[0071] As Figure 4 shown, in some embodiments of the present invention, the spectral line light source 110 may include a plurality of semiconductor lasers 111 and a switching mechanism 112 connected thereto. The characteristic spectral lines of the plurality of semiconductor lasers 111 can cover a wavelength range of 400 - 1000 nm, and their output power and full width at half maximum (FWHM) can both meet the calibration requirements. The semiconductor lasers 111 can output in a free space manner. Specifically, each semiconductor laser 111 can be alternatively switched by the switching mechanism 112 to the light inlet 122 of the integrating sphere 120 (i.e., the working position of the laser) to input the first incident light of the corresponding wavelength to the light inlet 122 of the integrating sphere 120, so as to ensure that only the output monochromatic light of the specified laser can be introduced into the integrating sphere 120 at the same time.

[0072] In some embodiments of the present invention, in order to further calibrate the spectral radiance of the imaging spectrometer, the integrating sphere 120 can also be equipped with a broadband light source 130 as an input, and its wavelength range can cover the visible-near infrared light in the wavelength range of 400nm to 1000nm. In the prior art, it is difficult for a single light source to provide a smooth, stable, and strong radiation output throughout this wavelength range. Therefore, in this embodiment, a combination of two light sources can be selected as the broadband light source 130 to calibrate the imaging spectrometer.

[0073] Specifically, as Figure 1 shown, the broadband light source 130 can be composed of a laser plasma light source 131 (Plasma External Lamp, PEL) and a quartz tungsten halogen lamp 132 (Quartz Tungsten Halogen, QTH). Among them, the laser plasma light source can output the first light in the wavelength range of 400 to 800nm, while the quartz tungsten halogen lamp can output the second light in the wavelength range of 800nm to 1000nm to form the second incident light.

[0074] It can be understood in combination with Figure 5A and Figure 5B Commonly understood. As Figure 5A shown, for the visible light band of 400 to 800nm, it is preferably to use the laser plasma light source 131 as the main light source, which can provide output light with strong power, high stability, and smooth spectral distribution as the second Lambertian light source within this wavelength range. Further, the laser plasma light source 131 can be approximately regarded as an ideal point light source. Therefore, an optical collimation system can be designed to collimate the output light of the laser plasma light source 131 and then introduce it into the light inlet 123 of the integrating sphere 120.

[0075] Continuing as Figure 5A shown, for the near infrared light band of 800 to 1000nm, the spectral distribution of the laser plasma light source is no longer smooth. For this, the quartz tungsten halogen lamp 132 can be selected as the main light source. As Figure 5B shown, the quartz tungsten halogen lamp can provide a light source with high irradiation intensity, high stability, and smooth spectral distribution in the wavelength range of 800 to 1000nm.

[0076] Further, in some preferred embodiments, in order to improve the energy utilization rate of the quartz tungsten halogen lamp 132 as much as possible, the broadband light source 130 can also include an optical reflection structure. Specifically, reference can be made to Figure 5C , Figure 5C shows a schematic structural diagram of the optical reflection structure supporting the quartz tungsten halogen lamp provided according to some embodiments of the present invention. As Figure 5CAs shown, in some embodiments, the optical reflection structure 510 can reflect and converge the scattered second light rays output by the quartz halogen tungsten lamp 132 to the light inlet 124 of the integrating sphere 120, thereby improving the light efficiency of the broadband light source 130.

[0077] In addition, considering that the radiation energy of the quartz halogen tungsten lamp 132 is mainly concentrated in the infrared band and has a strong thermal effect. In some alternative embodiments, the optical reflection structure 510 can also be equipped with heat dissipation devices ( Figure 5C not shown in the figure), such as heat sinks and fans, etc., to dissipate heat from the quartz halogen tungsten lamp 132 to reduce the thermal effect of the second light rays. In addition, the outer shell of the optical reflection structure 510 can also be made of black oxidized metal to further improve the heat dissipation efficiency.

[0078] Furthermore, in the above embodiments of the broadband light source, the calibration device 100 can further include variable apertures. As Figure 1 and Figure 2A shown, the calibration device 100 can include variable apertures 133 and 134, which are respectively located between the laser plasma light source 131 in the broadband light source 130 and its corresponding light inlet 123, and between the quartz halogen tungsten lamp 132 and its corresponding light inlet 124, for independently adjusting the light passing apertures of the incident light provided by the laser plasma light source 131 and the quartz halogen tungsten lamp 132, thereby changing the light passing aperture of the second incident light provided by the broadband light source 130 to adjust the irradiation intensity of the second spectral image.

[0079] The output light of the laser plasma light source 131 can be collimated and then introduced into the integrating sphere 120 through the electric variable aperture 133. The output light of the quartz halogen tungsten lamp 132 can be reflected and converged by the optical reflection structure 510 and then introduced into the integrating sphere 120 through the electric variable aperture 134.

[0080] Even further, although the quartz halogen tungsten lamp 132 is widely used as a spectral radiance standard light source, it is not the best choice for calibrating an imaging spectrometer. The reason is that the quartz halogen tungsten lamp 132 is actually a light source rich in red and near-infrared spectra but lacking in blue spectra, which will lead to a decrease in the signal-to-noise ratio of the measurement results of the imaging spectrometer in the blue band and saturation of the signal-to-noise ratio in the red and near-infrared bands, and ultimately cause spectral leakage or stray light in the imaging spectrometer. In this regard, in some preferred embodiments of the present invention, the calibration device 100 can also mix the light sources provided by the above laser plasma light source 131 and the quartz halogen tungsten lamp 132 through the integrating sphere 120, and then output a mixed-color second Lambertian light source through the light outlet 121.

[0081] Specifically, please refer to Figure 1 , Figure 2A and Figure 6 for a combined understanding.Figure 6 Shows the hybrid spectral diagram of a laser plasma light source (PEL) and a quartz halogen tungsten lamp (QTH) provided according to some embodiments of the present invention.

[0082] As Figure 1 , Figure 2A and Figure 6 shown, in some embodiments, the laser plasma light source 131 rich in the blue light spectrum can be obtained through the light inlet 123 in the integrating sphere 120, the quartz halogen tungsten lamp 132 rich in the red light and near-infrared spectrum can be obtained through the light inlet 124, and the two light sources are mixed in the integrating sphere 120, so that an ideal hybrid spectral output can be obtained at the light outlet 121 of the integrating sphere 120. As Figure 6 shown, in a 12-inch integrating sphere 120, the curve represents the spectral radiant luminance after the mixing of PEL and QTH, and its spectral radiant luminance performs well in the blue light, red light and near-infrared spectrum (400 - 1000 nm).

[0083] It should be emphasized that, in the embodiments of the present invention, in order to further calibrate the response linearity of the imaging spectrometer, therefore, the output light intensity of the integrating sphere type uniform surface light source must be adjustable. In the above embodiments, the light source provided by the laser plasma light source 131 and the quartz halogen tungsten lamp 132 can be independently adjusted by separately adjusting the variable apertures 133 and / or 134, so as to jointly change the light passing aperture of the second incident light, thereby adjusting the incident light of the integrating sphere 120, and further being able to adjust the intensity of its mixed-color outgoing light. At the same time, it can also ensure that the spectral distribution of the outgoing light remains unchanged during this process.

[0084] Next, please refer to Figure 7 , Figure 7 shows the spectral response range and photoelectric sensitivity curve diagram of a silicon photodiode provided according to some embodiments of the present invention.

[0085] In some embodiments of the present invention, in order to ensure that the integrating sphere 120 can output a stable spectral distribution and irradiation intensity on its light-emitting surface, the calibration device 100 may further include a spectral regulation system. Specifically, the spectral regulation system may include a spectral detection element and a light intensity detection element, which are respectively used to detect the spectral distribution and irradiation intensity of the first Lambert light source and the second Lambert light source, and send an adjustment instruction to the spectral line light source and / or the broadband light source, so that the difference between the detection results of their spectral distribution and irradiation intensity is within a preset range. As shown in Figure 2, the integrating sphere 120 may include a detection element interface 125, the diameter of which may be 12.7 mm, and is used to connect the spectral detection element or the light intensity detection element respectively.

[0086] Optionally, the spectral detection element may be a pre-calibrated standard spectrometer, and the light intensity detection element may be a silicon photodiode in a photoelectric sensor. AsFigure 7 As shown, in a typical working environment, the ambient temperature around the device or component is 25 degrees Celsius (Typ. Ta = 25 °C). The spectral response range of a silicon photodiode (e.g., a silicon photodiode of model S1336-BQ or S1336-BK) can cover the 190 - 1100 nm band, and its photoelectric sensitivity can reach 0.5 A / W. Also, the spectral response range of a standard spectrometer can cover the 400 - 1000 nm band, with a spectral resolution less than 2 nm, a wavelength accuracy better than 0.5 nm, and a measurement repeatability of up to 99%.

[0087] Furthermore, in some preferred embodiments, silicon photodiodes of different models can be selected according to the response requirements for a specific band. As Figure 7 shown, if there is a high response requirement for the band around 190 - 400 nm, a silicon photodiode of model S1336-BQ can be preferably selected.

[0088] Since the physical quantities measured by an imaging spectrometer cover multiple dimensions such as two-dimensional space, one-dimensional spectrum, and one-dimensional radiance, due to various factors such as the design limits of the imaging system, the production process of components, the assembly defects of the whole machine, and the internal stress release and aging of components, crosstalk will occur between physical quantities in multiple dimensions. Specifically, in combination with Figure 8A - 8C for a common understanding, taking smile and keystone distortions as examples, they are two types of crosstalk that seriously affect the performance indicators of an imaging spectrometer. Among them, smile distortion is a one-dimensional spectrum crosstalk, and keystone distortion is a two-dimensional space crosstalk. Due to the existence of crosstalk, the measurement results directly calibrated for an imaging spectrometer often have large errors. Therefore, before calibrating an imaging spectrometer, the influence degree of crosstalk can be preferably evaluated and corresponding corrections can be made.

[0089] Specifically, crosstalk evaluation and correction mainly include spectral crosstalk evaluation and correction, and spatial crosstalk evaluation and correction. Among them, spectral crosstalk evaluation and correction can include smile distortion crosstalk evaluation and correction, which is mainly for pushbroom imaging spectrometers, while spatial crosstalk evaluation and correction can include keystone distortion crosstalk evaluation and correction, which is mainly for pushbroom imaging spectrometers and staring imaging spectrometers. In some embodiments of the present invention, for this, different target plates can be placed at the light outlet 121 of the integrating sphere 120 to achieve the evaluation and correction of different crosstalks.

[0090] Specifically, please combine Figure 9A 、 Figure 9B ,and Figure 9C for a common understanding, among which Figure 9A shows a schematic structural diagram of a checkerboard target plate provided according to some embodiments of the present invention.Figure 9B shows a schematic structural diagram of a slit target board provided according to some embodiments of the present invention, Figure 9C shows a schematic structural diagram of a pinhole target board provided according to some embodiments of the present invention.

[0091] As Figure 9A shown, in some embodiments, the checkerboard target board 910 can be mainly used to evaluate and correct the two-dimensional spatial distortion crosstalk of a staring imaging spectrometer, where the black positions completely block light and the white positions are completely transparent.

[0092] The principle of using the checkerboard target board 910 to evaluate and correct the spatial distortion crosstalk is as follows: First, the checkerboard target board 910 can be installed at the light outlet 121 of the integrating sphere 120, and then the imaging spectrometer to be calibrated is used to sequentially measure the spectral images at various wavelengths. After that, by calculating the positions of the checkerboard corner points, the spatial mismatch characteristics (i.e., the spatial crosstalk characteristics) at various wavelengths can be quantitatively evaluated. Finally, based on the spatial mismatch calculation results, spatial crosstalk correction can be performed on the spectral images of the imaging spectrometer to be calibrated at various wavelengths.

[0093] As Figure 9B shown, in some embodiments, the slit target board 920 can be mainly used to evaluate and correct the smile distortion crosstalk of a pushbroom imaging spectrometer, where the length of the slit 921 can be greater than the length of the scanning line of the pushbroom imaging spectrometer, and the width of the image of the slit 921 on its focal plane array can be less than the physical width of one pixel.

[0094] The principle of using the slit target board 920 to evaluate and correct the smile distortion crosstalk is as follows: First, the slit target board 920 can be installed at the light outlet 121 of the integrating sphere 120. In the spectral line light source output mode, the pushbroom imaging spectrometer to be calibrated is used to sequentially measure the spectral images at various wavelengths. For an ideal imaging spectrometer without crosstalk, the measured spectral lines should be parallel to the direction of the scanning line. If the measured spectral lines deviate from the parallel direction of the scanning line, it indicates that the imaging spectrometer to be calibrated has smile distortion crosstalk, and the smile distortion crosstalk can be corrected by adjusting the imaging system or digital image processing methods.

[0095] Further, as Figure 9C shown, in some embodiments, the pinhole target board 930 can be mainly used to evaluate and correct the trapezoidal distortion crosstalk of a pushbroom imaging spectrometer, where the size of the image of the pinhole 931 on its focal plane array can be less than the physical size of one pixel.

[0096] The principle of evaluating and correcting trapezoidal distortion crosstalk using the pinhole target board 930 is as follows: First, the pinhole target board 930 can be installed at the light output port 121 of the integrating sphere 120. In the wide-spectrum light source output mode, the pinhole 931 can be moved along the scanning line of the pushbroom imaging spectrometer to be calibrated, and the spectral lines at various positions on the scanning line can be measured. For an ideal imaging spectrometer without crosstalk, the measured spectral lines should be perpendicular to the direction of the scanning line and there should be no bending. If the measured spectral lines deviate from or are bent in the perpendicular direction to the scanning line, it indicates that the imaging spectrometer to be calibrated has trapezoidal distortion crosstalk, and the trapezoidal distortion crosstalk can be corrected by adjusting the imaging system or digital image processing methods.

[0097] So far, the main structure of the calibration device 100 of the imaging spectrometer provided in the first aspect of the present invention has been basically introduced. Through the research on the principle of spectral imaging technology and the performance indicators of the imaging spectrometer, the present invention provides an integrating sphere type uniform surface light source as the Lambert space and angular spectral radiation field, and based on this integrating sphere type uniform surface light source, a set of calibration device 100 of the imaging spectrometer is built, which can realize the free switching between the spectral line light source and the wide-spectrum light source, and combine the spectral mixing and spectral regulation technologies to ensure that the calibration device can output uniform, stable, and intensity-adjustable spectra and radiance on its light output surface. The spectral line light source can include semiconductor laser light sources with different wavelengths and their mechanical switching mechanisms. The wide-spectrum light source can include a laser plasma light source and its optical collimation system, a quartz halogen tungsten lamp and its optical reflection system. The spectral mixing system can include an integrating sphere and an electrically variable aperture. The spectral regulation system can include a photoelectric sensor (such as a silicon photodiode) and a spectrometer.

[0098] Next, based on the controller, combined with the calibration method of the imaging spectrometer provided in another aspect, the working principle of the calibration device 100 of the imaging spectrometer will be further introduced.

[0099] It can be combined Figure 10 to understand together Figure 10 which shows a flowchart of the calibration method of the imaging spectrometer provided according to some embodiments of the present invention.

[0100] As Figure 10 shown, in some embodiments of the present invention, the calibration method of the imaging spectrometer may include step S11: Switch the spectral line light source of the calibration device to the light input port of its integrating sphere to form a first Lambert light source with a corresponding wavelength range at the light output port of the integrating sphere, and enable the imaging spectrometer to be calibrated to obtain a corresponding first spectral map.

[0101] Specifically, in some embodiments of the present invention, the first incident light emitted by the spectral line light source is directly introduced into the integrating sphere 120 to form a uniform and stable single-wavelength spectral radiation field at the light outlet 121 of the integrating sphere 120, the size of which can cover the field of view of the imaging spectrometer to be calibrated, so as to be used for calibrating the wavelength accuracy and spectral resolution of the imaging spectrometer.

[0102] Continuing as Figure 10 shown, the calibration method of the above imaging spectrometer provided by the present invention may further include step S12: switching the broadband light source of the calibration device to the light inlet of the integrating sphere to form a second Lambertian light source corresponding to a wavelength range at the light outlet of the integrating sphere, and enabling the imaging spectrometer to acquire a corresponding second spectral image.

[0103] Specifically, in some embodiments of the present invention, the second incident light emitted by the broadband light source preferably can first change the light passing aperture of the second incident light through an electric variable aperture diaphragm multiple times to adjust the irradiation intensity of the second spectral image, and then, according to the change of the irradiation intensity, it can be used for calibrating the radiance response of the imaging spectrometer in multiple wavelength ranges. In this embodiment, by changing the input light of the integrating sphere 120 through the variable aperture diaphragm, a uniform, stable and intensity-adjustable full-band spectral radiation field can be formed at the light outlet 121 of the integrating sphere 120, so as to be used for calibrating the radiance response of the imaging spectrometer.

[0104] In this embodiment, in order to comprehensively evaluate the radiance response of the imaging spectrometer at each wavelength, the output light intensity of the integrating sphere type uniform surface light source must be adjustable, and its range can cover the complete dynamic range of the imaging spectrometer, and based on this, the evaluation work of technical indicators such as noise, dynamic range, linearity, and stray light is carried out.

[0105] Continuing as Figure 10 shown, the calibration method of the above imaging spectrometer provided by the present invention may further include step S13: calibrating the imaging spectrometer according to the first spectral image and the second spectral image.

[0106] In some alternative embodiments, when the imaging spectrometer to be calibrated is a staring imaging spectrometer, it can be calibrated by a checkerboard target board. Specifically, as Figure 11 shown, step S13 can be embodied as steps S131 and S132.

[0107] It can be understood in combination with Figure 1 , Figure 9A and Figure 11 collectively that first, step S131 can be executed: switching the broadband light source to the light inlet of the integrating sphere and placing the checkerboard target board at the light outlet of the integrating sphere to obtain second spectral images of the staring imaging spectrometer in multiple wavelength ranges.

[0108] Specifically, a checkerboard target board 910 is installed at the light outlet 121 of the integrating sphere 120, and the input light source is switched to a broadband light source. Then, the spectral images at various wavelengths can be sequentially measured using the staring imaging spectrometer to be calibrated, so as to obtain the second spectral images of the staring imaging spectrometer within multiple wavelength ranges.

[0109] After that, step S132 can be executed: Based on the corner positions of multiple checkerboards in the checkerboard target board, the spatial crosstalk of the staring imaging spectrometer is evaluated and corrected.

[0110] Specifically, the corner positions of the checkerboards in the checkerboard target board 910 can be calculated to evaluate the spatial mismatch characteristics of the staring imaging spectrometer at various wavelengths. Then, based on the calculation results of the spatial mismatch, the spatial mismatch correction can be performed on the second spectral images at various wavelengths.

[0111] Furthermore, after completing the above evaluation and correction of the spatial mismatch crosstalk of the staring imaging spectrometer, the current checkerboard target board 910 can be removed, the spectral line light source is switched to the light inlet 122 of the integrating sphere 120, and the staring imaging spectrometer is used to sequentially measure the first spectral images at multiple spectral line wavelengths, and the wavelength accuracy and spectral resolution of the imaging spectrometer are calibrated.

[0112] Even further, after that, the input light source can be switched to the broadband light source again, and by adjusting the electric variable aperture, the radiometric response of the staring imaging spectrometer at various wavelengths is calibrated in sequence.

[0113] In some other alternative embodiments, when the imaging spectrometer to be calibrated is a pushbroom imaging spectrometer, a pinhole target board and a slit target board can be combined to calibrate it. Specifically, as Figure 12 shown, step S13 can be embodied as steps S133 to S135.

[0114] First, it can be combined with Figure 1 , Figure 9C and Figure 12 to understand together. First, step S133 can be executed: Switch the broadband light source to the light inlet of the integrating sphere, and place the pinhole target board at the light outlet of the integrating sphere to obtain the linearity and direction information of the spectral lines at the pinholes on the scanning line of the pushbroom imaging spectrometer.

[0115] Specifically, first install the pinhole target board 930 at the light outlet 121 of the integrating sphere 120, and switch the input light source to a broadband light source. Place the pinhole 931 of the pinhole target board 930 on the scanning line of the pushbroom imaging spectrometer to be calibrated, and measure the linearity and direction information of the spectral line at the pinhole 931 on the scanning line. Then, the pinhole 931 can be moved along the scanning line of the pushbroom imaging spectrometer, and the linearity and direction information of the spectral lines at multiple positions on the scanning line can be measured and obtained.

[0116] After that, step S134 can be executed: Switch the spectral line light source to the light inlet of the integrating sphere, and replace the pinhole target board with a slit target board to obtain the linearity and direction information of the spatial lines in multiple wavelength ranges at the slit on the scanning line of the pushbroom imaging spectrometer.

[0117] Specifically, it can be further combined with Figure 1 、 Figure 9B and Figure 12 to be understood together. Remove the pinhole target board 930 to replace it with a slit target board 920, and switch the input light source to a spectral line light source. The slit 921 in the slit target board 920 can be aligned with the scanning line of the pushbroom imaging spectrometer, and the linearity and direction information of the spatial lines in each wavelength range can be measured and obtained.

[0118] After that, step S135 can be executed: Based on the linearity and direction information of the spectral lines and spatial lines, evaluate and correct the spectral crosstalk and spatial crosstalk of the pushbroom imaging spectrometer.

[0119] Specifically, in response to the spectral line measured via the pinhole target board 930 deviating or bending from the perpendicular direction of the scanning line, it is determined that the pushbroom imaging spectrometer has trapezoidal distortion crosstalk, and the trapezoidal distortion crosstalk is corrected so that the spectral line is perpendicular to the direction of the scanning line. In addition, in response to the spatial line measured via the slit target board 920 deviating from the parallel direction of the scanning line, it is determined that the pushbroom imaging spectrometer has smile distortion crosstalk, and the smile distortion crosstalk is corrected so that the spatial line is parallel to the direction of the scanning line. That is to say, after correction, both the spectral line and the spatial line are kept straight.

[0120] Furthermore, optionally, after completing the above evaluation and correction of the trapezoidal distortion crosstalk and smile distortion crosstalk of the pushbroom imaging spectrometer, the current slit target board 920 can be removed, and the spectral line light source can be switched to the light inlet 122 of the integrating sphere 120. The pushbroom imaging spectrometer is used to sequentially measure and obtain the first spectral images at multiple spectral line wavelengths, and the wavelength accuracy and spectral resolution of the imaging spectrometer are calibrated.

[0121] Further, after that, the input light source can be switched to a broadband light source again, and by adjusting the electric variable aperture, the radiometric response of the push-broom imaging spectrometer at each wavelength can be calibrated in sequence.

[0122] Although the above methods are illustrated and described as a series of actions for simplicity of explanation, it should be understood and appreciated that these methods are not limited by the order of the actions, because according to one or more embodiments, some actions may occur in a different order and / or concurrently with other actions that are illustrated and described herein or that are not illustrated and described herein but are understood by those skilled in the art.

[0123] Through the calibration method of the above imaging spectrometer, based on the fact that the physical quantity measurement of the imaging spectrometer covers multiple dimensions such as two-dimensional space, one-dimensional spectrum, and one-dimensional radiance, combined with factors such as the design limit of its imaging system, the production process of components, and the assembly defects of the whole machine, the occurrence mechanism of crosstalk in multiple dimensions can be studied, the influence of crosstalk on its measurement results can be evaluated, and corresponding crosstalk correction methods can be proposed to improve the measurement level of the whole calibration device. Crosstalk evaluation and correction can include spectral crosstalk evaluation and correction, and spatial crosstalk evaluation and correction. Spectral crosstalk evaluation and correction mainly can include smile distortion, for push-broom imaging spectrometers, while spatial crosstalk evaluation and correction mainly can include trapezoidal distortion, for push-broom imaging spectrometers and staring imaging spectrometers.

[0124] Further, in some preferred practical examples, since the calibration device 100 can be equipped with a spectral detection element and a light intensity detection element as monitoring sensors for spectral distribution and irradiance intensity respectively, therefore, in the above calibration step, the monitoring results between the two can also be compared to make the difference between the detection results of the spectral distribution and the irradiance intensity within a preset range, so as to ensure the output stability of the spectral distribution and the irradiance intensity on the light exit surface of the integrating sphere 120. And when there is a large difference in the readings of the two, the spectral distribution and the irradiance intensity on the light exit surface can be recalibrated.

[0125] Those skilled in the art will further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or a combination of the two. To clearly illustrate this interchangeability of hardware and software, the various illustrative components, blocks, modules, circuits, and steps are described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the particular application and the design constraints imposed on the overall system. Skilled artisans may implement the described functionality in different ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

[0126] The various illustrative logical modules and circuits described in connection with the embodiments disclosed herein can be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0127] The steps of a method or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read from, and write to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

[0128] In one or more exemplary embodiments, the described functionality may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software as a computer program product, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or code. The computer-readable medium includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. The storage media may be any available media that can be accessed by a computer. By way of example and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a web site, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the medium. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disk generally reproduces data magnetically, while disc uses lasers to optically reproduce data. Combinations of the above should also be included within the scope of computer-readable media.

[0129] In summary, the present invention provides a calibration device for an imaging spectrometer, a calibration method for an imaging spectrometer, and a computer-readable storage medium, which can simultaneously meet the calibration requirements for multiple parameters in the imaging spectrometer, ensure that a uniform, stable, and intensity-adjustable spectrum and radiance can be output on its light exit surface. At the same time, it can also avoid crosstalk between physical quantities in multiple dimensions, thereby improving the measurement level of the entire calibration device.

[0130] The foregoing description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A calibration device for an imaging spectrometer, characterized in that: include: A light source group, including a spectral line light source, a broadband light source and a switching mechanism; An integrating sphere, used for receiving the first incident light emitted by the spectral line light source and the second incident light emitted by the broadband light source in a time-sharing manner, so as to form a first Lambertian light source and a second Lambertian light source of corresponding wavelength ranges at its light outlet, respectively, and to enable the imaging spectrometer to be calibrated to obtain the corresponding first spectral image and second spectral image; as well as The controller is configured to calibrate the imaging spectrometer according to the first spectral image and the second spectral image.

2. The calibration device according to claim 1, characterized in that The calibration device further includes a variable iris, which is located between the broadband light source and the light inlet of the integrating sphere and is used to change the aperture of the second incident light to adjust the irradiation intensity of the second spectral image. The step of calibrating the imaging spectrometer according to the first spectral image and the second spectral image includes: changing the clear aperture of the second incident light multiple times via the variable aperture to adjust the irradiance intensity of the second spectral image; and calibrating the radiometric response of the imaging spectrometer in the multiple wavelength ranges according to the change of the irradiance intensity.

3. The calibration device according to claim 1, characterized in that The imaging spectrometer includes a staring imaging spectrometer, and the calibration device also includes a checkerboard target plate. The step of calibrating the imaging spectrometer according to the first spectral image and the second spectral image comprises: switching the wide-spectrum light source to the light inlet of the integrating sphere, and placing the checkerboard target plate at the light outlet of the integrating sphere, so as to obtain a second spectral image of the staring-type imaging spectrometer within a plurality of wavelength ranges; and evaluating and correcting spatial crosstalk of the staring-type imaging spectrometer based on the corner point positions of a plurality of checkerboards in the checkerboard target plate.

4. The calibration device according to claim 3, characterized in that The step of evaluating and correcting the spatial crosstalk of the staring imaging spectrometer based on the corner point positions of a plurality of checkerboards in the checkerboard target plate comprises: Calculating the corner point position of each checkerboard in the checkerboard target plate to evaluate the spatial mismatch characteristics of the staring imaging spectrometer at each wavelength; and Based on the spatial mismatch calculation result, spatial mismatch correction is performed on the second spectral image at each wavelength.

5. The calibration device according to claim 1, characterized in that: The imaging spectrometer includes a push-broom imaging spectrometer, and the calibration device also includes a pinhole target plate and a slit target plate. The step of calibrating the imaging spectrometer according to the first spectral image and the second spectral image comprises: switching the wide-spectrum light source to the light inlet of the integrating sphere, and placing the pinhole target plate at the light outlet of the integrating sphere, so as to obtain the linearity and direction information of the spectral line at the pinhole on the scanning line of the push-broom imaging spectrometer; switching the spectral line light source to the light inlet of the integrating sphere, and replacing the pinhole target plate with the slit target plate, so as to obtain the linearity and direction information of the spatial lines within multiple wavelength ranges at the slit on the scanning line of the push-broom imaging spectrometer; and evaluating and correcting the spectral crosstalk and spatial crosstalk of the push-broom imaging spectrometer based on the linearity and direction information of the spectral lines and the spatial lines.

6. The calibration device according to claim 5, characterized in that The spatial crosstalk includes trapezoidal distortion crosstalk, the spectral crosstalk includes smile distortion crosstalk, and the step of evaluating and correcting the spectral crosstalk and spatial crosstalk of the push-broom imaging spectrometer based on the linearity and direction information of the spectral line and the spatial line includes: In response to the spectral line measured through the pinhole target plate deviating from or bending in a direction perpendicular to the scanning line, determining that the push-broom imaging spectrometer has keystone crosstalk, and correcting the keystone crosstalk so that the spectral line is perpendicular to the scanning line; and In response to the deviation of the spatial line measured through the slit target plate from the parallel direction of the scanning line, it is determined that the push-broom imaging spectrometer has smile distortion crosstalk, and the smile distortion crosstalk is corrected to make the spatial line parallel to the direction of the scanning line.

7. The calibration device according to claim 5, characterized in that The step of obtaining the linearity and direction information of the spectral line at the pinhole located on the scanning line of the push-broom imaging spectrometer comprises: positioning the pinhole of the pinhole target plate on the scanning line of the push-broom imaging spectrometer, and obtaining the linearity and direction information of the spectral line at the pinhole on the scanning line; and moving the pinhole along the scanning line of the push-broom imaging spectrometer, and measuring the linearity and direction information of the spectral line at multiple positions on the scanning line. The step of obtaining linearity and direction information of spatial lines within multiple wavelength ranges at a slit located on a scanning line of the push-broom imaging spectrometer comprises: aligning the slit in the slit target plate with the scanning line of the push-broom imaging spectrometer, and obtaining linearity and direction information of spatial lines within each of the wavelength ranges.

8. The calibration device according to claim 3 or 5, characterized in that: The controller is also configured to: After performing the crosstalk evaluation and correction, removing the current target plate, and switching the spectral line light source to the light inlet of the integrating sphere; and The first spectral images at multiple spectral line wavelengths are acquired by the imaging spectrometer to calibrate the wavelength accuracy and spectral resolution of the imaging spectrometer.

9. The calibration device according to claim 1, characterized in that: The calibration device also includes a spectral control system, which includes a spectral detection element and a light intensity detection element, which are respectively used to detect the spectral distribution and irradiation intensity of the first Lambertian light source and the second Lambertian light source, and send adjustment instructions to the spectral line light source and / or the wide-spectrum light source so that the difference between the detection results of their spectral distribution and irradiation intensity is within a preset range.

10. The calibration device according to claim 1, characterized in that: The integrating sphere includes two light inlets for respectively receiving the first incident light and the second incident light. The interior of the integrating sphere is coated with a diffuse reflection material with high reflectivity. A baffle is provided between the two light inlets and the light outlet to form the first Lambertian light source or the second Lambertian light source at the light outlet.

11. The calibration device according to claim 1, characterized in that: The spectral line light source includes a plurality of semiconductor lasers, whose characteristic spectral lines cover the (400-1000) nm band range. Each of the semiconductor lasers is selectively switched to the light inlet of the integrating sphere by the switching mechanism to input the first incident light of the corresponding wavelength into the integrating sphere.

12. The calibration device according to claim 1, characterized in that The broadband light source is composed of a laser plasma light source and a quartz tungsten halogen lamp, wherein the laser plasma light source outputs a first light in the wavelength range of 400nm to 800nm, and the quartz tungsten halogen lamp outputs a second light in the wavelength range of 800nm ​​to 1000nm to constitute the second incident light.

13. The calibration device according to claim 12, characterized in that The broadband light source further comprises: An optical reflection structure is used to reflect the scattered second light output by the quartz tungsten halogen lamp to the light inlet of the integrating sphere to improve the light efficiency of the broadband light source, and / or The heat dissipation device is used to dissipate heat for the quartz tungsten halogen lamp to reduce the thermal effect of the second light.

14. A calibration method for an imaging spectrometer, characterized in that: The following steps are involved: Switching the spectral line light source of the calibration device according to any one of claims 1 to 13 to the light inlet of its integrating sphere to form a first Lambertian light source of the corresponding wavelength range at the light outlet of the integrating sphere, and enabling the imaging spectrometer to be calibrated to acquire the corresponding first spectral image; Switching the wide-spectrum light source of the calibration device to the light inlet of the integrating sphere to form a second Lambertian light source of the corresponding wavelength range at the light outlet of the integrating sphere, and enabling the imaging spectrometer to acquire a corresponding second spectrum image; as well as The imaging spectrometer is calibrated according to the first spectral image and the second spectral image.

15. A computer-readable storage medium having computer instructions stored thereon, characterized in that: When the computer instructions are executed by a processor, the calibration method for an imaging spectrometer as claimed in claim 14 is implemented.

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