Airglow Spectral Imaging System

Abstract

The present invention provides an airglow spectrum imaging system, comprising a spherical window, an imaging lens assembly, a field lens, a relay telecentric imaging lens assembly and a camera, wherein the spherical window is suitable for transmitting an initial airglow beam generated by the atmosphere; the imaging lens assembly is suitable for simultaneously imaging multiple spectral bands of the initial airglow beam and outputting multiple airglow imaging beams; the field lens is suitable for converting the airglow imaging beam into a telecentric beam and correcting the telecentric beam; the relay telecentric imaging lens assembly is suitable for imaging the corrected telecentric beam; and the camera is suitable for collecting multiple images generated by the relay telecentric imaging lens assembly, the multiple images respectively corresponding to the multiple spectral bands of the initial airglow beam, wherein the relay telecentric imaging lens assembly comprises a first convex lens and a second convex lens, and the relationship between the focal length of the first convex lens and the focal length of the second convex lens satisfies.

Description

Technical Field

[0001] At least one embodiment of the present invention relates to the technical field of multi-spectral airglow imaging observation, and more specifically to an airglow spectral imaging system. Background Art

[0002] Airglow is a weak luminous phenomenon in the middle and upper atmosphere of the Earth. It is mainly caused by the gas or atomic components in the atmosphere absorbing the solar radiation energy and emitting a weak glow in the photochemical process. Due to the different gas or atomic components at different altitudes, the characteristic light band ranges emitted are different. The atmospheric information at different altitudes is monitored by monitoring the airglow of different gas or atomic components. The components of airglow include OH, Na, N2, O2, CO2, OI, etc., which radiate the corresponding characteristic spectrum through the transition of vibration and rotation energy levels. Since the intensity of the radiation spectrum is modulated by the atmospheric dynamic process, the spatial distribution characteristics of atmospheric fluctuations can be studied by detecting the two-dimensional spatial variation information of the spectrum intensity.

[0003] The multi-spectral airglow imaging system mainly images the airglow luminous layer, and uses filters to achieve imaging of airglow in different bands of a wide range of the sky. It has the advantages of simple spectral information acquisition, real-time fast static imaging, long measurement distance, small structure size, and low price. By studying the changes in atmospheric airglow, we can understand important physical phenomena in the middle and high atmosphere, such as atmospheric gravity waves, atmospheric temperature, wind fields, tidal waves, planetary waves, and small and medium irregular body structures, which is of great significance to the recognition and understanding of the structure and physical processes of the middle and high atmosphere.

[0004] The multi-spectral airglow imager in the related technology sets a filter wheel or slot inside the wide-angle lens, and collects multiple wavelength spectra radiated by the same target and the same gas component by rotating or plugging and unplugging the filter, and finally images the collected light information on the photosensitive surface of the high-sensitivity camera, thereby achieving spatial resolution and spectral resolution. The traditional filter switching imaging method determines that the acquisition time of spectral information of different wavelengths is different, which not only affects the time resolution of the observation, but also fails to obtain rapidly changing spectral intensity information, affecting the accuracy of the instrument's final detection object. Summary of the invention

[0005] In order to solve at least one of the above-mentioned and other technical problems in the prior art, the present invention provides an airglow spectral imaging system, which can achieve wide-angle airglow imaging with an angle of more than 120° and simultaneously image multiple spectral bands of the airglow beam generated by the atmosphere, thereby improving the temporal resolution of airglow beam imaging.

[0006] According to one aspect of the present invention, there is provided an airglow spectrum imaging system, comprising:

[0007] Spherical window, suitable for transmitting the initial airglow beam generated by the atmosphere;

[0008] An imaging lens assembly, adapted to simultaneously image multiple spectral bands of the initial airglow beam and output multiple airglow imaging beams;

[0009] A field lens, adapted to transform the airglow imaging beam into a telecentric beam and to correct the telecentric beam;

[0010] A relay telecentric imaging lens assembly, adapted to image the corrected telecentric beam; and

[0011] A camera, adapted to collect a plurality of images generated by the relay telecentric imaging lens assembly, wherein the plurality of images correspond one-to-one to a plurality of spectral bands of the initial airglow beam;

[0012] The above-mentioned relay telecentric imaging lens assembly includes a first convex lens and a second convex lens, and the focal length of the above-mentioned first convex lens is and the second convex lens The relationship between the focal lengths satisfies: .

[0013] According to an embodiment of the present invention, the imaging lens assembly comprises a plurality of wide-angle imaging lenses, wherein the wide-angle imaging lenses are reverse telephoto imaging lenses.

[0014] The plurality of wide-angle imaging lenses are centrally symmetrically arranged on a projection surface along the central axis of the airglow spectrum imaging system, and the optical axes of the plurality of wide-angle imaging lenses are parallel to the central axis.

[0015] According to an embodiment of the present invention, the first convex lens is adapted to focus the telecentric light beam to form a focused light beam; and the second convex lens is adapted to image the focused light beam;

[0016] Among them, the focal length of the first convex lens is Meet 100mm< <300mm, the focal length of the second convex lens Meet 10mm< <100mm.

[0017] According to an embodiment of the present invention, the above-mentioned airglow spectrum imaging system further includes:

[0018] A field of view aperture adapted to filter out light beams outside the field of view angle required by the airglow spectral imaging system to avoid overlap of the multiple images collected by the camera; and

[0019] The filter is adapted to allow a beam of a specific wavelength in the corrected telecentric beam to pass.

[0020] According to an embodiment of the present invention, the number of the above-mentioned filters is the same as the number of the above-mentioned wide-angle imaging lenses and is four, and the above-mentioned filters are all narrow-band filters.

[0021] According to an embodiment of the present invention, the number of the above-mentioned field stops is the same as the number of the above-mentioned wide-angle imaging lenses and is four, and the shape of the above-mentioned field stop is rectangular to improve the utilization rate of the pixel size of the above-mentioned camera.

[0022] According to an embodiment of the present invention, the aperture D of the above-mentioned spherical window satisfies 100 mm < D < 300 mm, and the relationship between the thickness t of the above-mentioned spherical window and the aperture D of the above-mentioned spherical window satisfies 10 < D / t < 30.

[0023] According to an embodiment of the present invention, the focal length of the above-mentioned wide-angle imaging lens is f c satisfies 10 mm < f c < 40 mm, the field of view angle w of the above-mentioned wide-angle imaging lens satisfies 120° < w < 180°, and the imaging wavelength wav of the above-mentioned wide-angle imaging lens satisfies 1500 nm < wav < 1600 nm.

[0024] According to an embodiment of the present invention, the focal length F of the above-mentioned field lens w satisfies F w > 20 mm, the above-mentioned field lens changes the above-mentioned airglow imaging beam into a telecentric beam and corrects the above-mentioned telecentric beam to reduce the angular deviation of the corrected above-mentioned telecentric beam incident on the above-mentioned filter.

[0025] According to an embodiment of the present invention, the focal length F of the above-mentioned airglow spectral imaging system satisfies F = f c × m;

[0026] wherein, f c is the focal length of the above-mentioned wide-angle imaging lens, m is the imaging magnification of the above-mentioned relay telecentric imaging lens assembly, and m satisfies 0.1 < m < 0.5.

[0027] According to an embodiment of the present invention, an initial airglow beam generated by the atmosphere is transmitted through a spherical window; an imaging lens assembly is used to image multiple spectral bands of the initial airglow beam simultaneously and output multiple airglow imaging beams; a field lens is used to change the airglow imaging beam into a telecentric beam and correct the telecentric beam; a relay telecentric imaging lens assembly is used to image the corrected telecentric beam; a camera is used to collect multiple images generated by the relay telecentric imaging lens assembly, and the multiple images respectively correspond to multiple spectral bands of the initial airglow beam one by one; the relay telecentric imaging lens assembly includes a first convex lens and a second convex lens, and the focal length of the first convex lens and the focal length of the second convex lens , achieving wide-angle airglow imaging of more than 120°, and simultaneously imaging multiple spectral bands of the airglow beam generated by the atmosphere (i.e., the initial airglow beam), improving the temporal resolution of airglow beam imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above contents and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0029] Figure 1 A working principle diagram of an airglow spectrum imaging system according to an embodiment of the present invention is shown;

[0030] Figure 2 A schematic diagram showing an arrangement of multiple aperture units of a relay telecentric imaging lens assembly in an airglow spectral imaging system according to an embodiment of the present invention is shown;

[0031] Figure 3 An enlarged view of the structure of a spherical window in an airglow spectrum imaging system according to an embodiment of the present invention is shown;

[0032] Figure 4 A schematic diagram of imaging distribution of a camera photosensitive surface in an airglow spectrum imaging system according to an embodiment of the present invention is shown;

[0033] Figure 5 A distortion curve diagram of imaging of a single aperture unit in a relay telecentric imaging lens assembly in an airglow spectral imaging system according to an embodiment of the present invention is shown;

[0034] Figure 6 shows the wave shape of a gravity wave with a wavelength of 1.5 km according to an embodiment of the present invention; and

[0035] Figure 7 The imaging resolution diagram of the wave shape of a gravity wave with a wavelength of 1.5 km after passing through the airglow spectrum imaging system according to an embodiment of the present invention is shown.

[0036] In the above drawings, the meanings of the reference numerals are as follows:

[0037] 1-spherical window;

[0038] 2- Imaging lens assembly;

[0039] 201-Wide-angle imaging lens;

[0040] 3- Field lens;

[0041] 4- Field stop;

[0042] 5-Filter;

[0043] 6-Relay telecentric imaging lens assembly;

[0044] 601- first convex lens;

[0045] 602- second convex lens;

[0046] a-first aperture unit;

[0047] b-second aperture unit;

[0048] c-third aperture unit;

[0049] d-the fourth aperture unit;

[0050] 7- Camera;

[0051] 701-first image;

[0052] 702 - second image;

[0053] 703- third image;

[0054] 704- fourth image;

[0055] 8-Central axis of the airglow spectral imaging system;

[0056] 9- incident end face;

[0057] 10-Exit end face. DETAILED DESCRIPTION

[0058] Below, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of concepts of the present invention.

[0059] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0060] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0061] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0062] The multi-spectral airglow imager in the related technology sets a filter wheel or slot inside the wide-angle lens, and collects multiple wavelength spectra radiated by the same target and the same gas component by rotating or plugging and unplugging the filter, and finally images the collected light information on the photosensitive surface of the high-sensitivity camera, thereby achieving spatial resolution and spectral resolution. The traditional filter switching imaging method determines that the acquisition time of spectral information of different wavelengths is different, which not only affects the time resolution of the observation, but also fails to obtain rapidly changing spectral intensity information, affecting the accuracy of the instrument's final detection object.

[0063] In view of this, the present invention provides an airglow spectral imaging system, which is provided with a spherical window to transmit an initial airglow beam generated by the atmosphere; an imaging lens assembly is used to simultaneously image multiple spectral bands of the initial airglow beam, and multiple airglow imaging beams are output; a field lens is used to convert the airglow imaging beam into a telecentric beam, and the telecentric beam is corrected; a relay telecentric imaging lens assembly is used to image the corrected telecentric beam; a camera is used to collect multiple images generated by the relay telecentric imaging lens assembly, and the multiple images correspond one-to-one to the multiple spectral bands of the initial airglow beam, respectively, and the relay telecentric imaging lens assembly includes a first convex lens and a second convex lens, and the focal length of the first convex lens is and the second convex lens The relationship between the focal lengths satisfies , achieving wide-angle airglow imaging of more than 120°, and simultaneously imaging multiple spectral bands of the initial airglow beam generated by the atmosphere, improving the temporal resolution of airglow beam imaging.

[0064] Figure 1 The working principle diagram of the airglow spectrum imaging system according to an embodiment of the present invention is shown.

[0065] According to some embodiments of the present invention, Figure 1As shown, the above-mentioned airglow spectrum imaging system includes: a spherical window 1, an imaging lens assembly 2, a field lens 3, a relay telecentric imaging lens assembly 6 and a camera 7, the spherical window 1 is suitable for transmitting the initial airglow beam generated by the atmosphere; the imaging lens assembly 2 is suitable for simultaneously imaging multiple spectral bands of the initial airglow beam and outputting multiple airglow imaging beams; the field lens 3 is suitable for converting the airglow imaging beam into a telecentric beam and correcting the telecentric beam; the relay telecentric imaging lens assembly 6 is suitable for imaging the corrected telecentric beam; and the camera 7 is suitable for collecting multiple images generated by the relay telecentric imaging lens assembly 6, and the multiple images correspond one by one to the multiple spectral bands of the initial airglow beam; the relay telecentric imaging lens assembly includes a first convex lens and a second convex lens, and the focal length of the first convex lens is and the second convex lens The relationship between the focal lengths satisfies .

[0066] According to some embodiments of the present invention, a spherical window is provided to transmit an initial airglow beam generated by the atmosphere; an imaging lens assembly is used to simultaneously image multiple spectral bands of the initial airglow beam, and multiple airglow imaging beams are output; a field lens is used to convert the airglow imaging beam into a telecentric beam; a relay telecentric imaging lens assembly is used to image the telecentric beam; a camera is used to collect multiple images generated by the relay telecentric imaging lens assembly, and the multiple images correspond one-to-one to the multiple spectral bands of the initial airglow beam; the relay telecentric imaging lens assembly includes a first convex lens and a second convex lens, and the focal length of the first convex lens is and the second convex lens The relationship between the focal lengths satisfies , achieving wide-angle airglow imaging of more than 120°, and simultaneously imaging multiple spectral bands of the initial airglow beam generated by the atmosphere, improving the temporal resolution of airglow beam imaging.

[0067] According to some embodiments of the present invention, the imaging lens assembly 2 includes a plurality of wide-angle imaging lenses 201, and the wide-angle imaging lenses 201 are reverse telephoto imaging lenses, wherein the plurality of wide-angle imaging lenses 201 are centrally symmetrically arranged on a projection surface along a central axis 8 of the airglow spectrum imaging system, and the optical axes of the plurality of wide-angle imaging lenses 201 are parallel to the central axis 8.

[0068] According to some alternative embodiments of the present invention, the reverse telephoto imaging lens comprises a combination of a concave lens and a convex lens, the focal length of the front lens group of the reverse telephoto imaging lens is negative, and the focal length of the rear lens group is positive. The number of the plurality of wide-angle imaging lenses 201 comprises four, and the plurality of wide-angle imaging lenses 201 respectively images the four spectral bands of the initial airglow beam.

[0069] According to some embodiments of the present invention, the number of the wide-angle imaging lenses 201 depends on the shape and size of the photosensitive surface of the camera. When the photosensitive surface of the camera is square, the number of the wide-angle imaging lenses 201 is four, and they are arranged in central symmetry on the projection plane along the central axis 8 of the airglow spectral imaging system, which improves the pixel utilization rate of the photosensitive surface of the camera and at the same time improves the consistency of the aberration and distortion responses of each imaging channel in the airglow spectral imaging system. By setting the optical axes of the multiple wide-angle imaging lenses 201 to be parallel to the central axis 8, each wide-angle imaging lens 201 can image the same target airglow region.

[0070] According to some embodiments of the present invention, the focal length of the wide-angle imaging lens 201 is f c satisfying 10 mm < f c < 40 mm, the field of view angle w of the wide-angle imaging lens 201 satisfies 120° < w < 180°, and the imaging wavelength wav of the wide-angle imaging lens 201 satisfies 1500 nm < wav < 1600 nm.

[0071] According to some embodiments of the present invention, as Figure 1 shown, the above-mentioned airglow spectral imaging system further includes a field stop 4 and a filter 5. The field stop 4 is suitable for filtering out the light beams outside the required field of view angle of the above-mentioned airglow spectral imaging system to avoid the overlap of multiple images collected by the camera 7; and the filter 5 is suitable for allowing the light beams of specific wavelengths in the corrected telecentric light beams to pass through.

[0072] According to some embodiments of the present invention, the initial airglow beam is imaged multiple times by the airglow spectral imaging system. When the initial airglow beam is incident on the wide-angle imaging lens 201, the combination of the concave lens and the convex lens in the wide-angle imaging lens 201 will perform divergence and convergence processing on the initial airglow beam, and form a clear intermediate image at a certain position behind the wide-angle imaging lens 201. The position of the intermediate image is at the field stop 4, and the intermediate image is further imaged on the photosensitive surface of the camera 7 by the relay telecentric imaging lens assembly 6, and finally multiple images corresponding to the multiple spectral bands of the initial airglow beam are obtained.

[0073] According to some embodiments of the present invention, the setting of the field stop 4 filters out the light beams outside the required field of view angle of the above-mentioned airglow spectral imaging system, avoids the overlap of the light beams incident on the photosensitive surface of the camera 7, and avoids the overlap of multiple images collected by the camera 7. The setting of the filter 5 allows the light beams of specific wavelengths in the telecentric light beams to pass through, achieving frequency selection of the spectral bands of the initial airglow beam to be detected and suppressing the influence of other spectral bands.

[0074] According to some embodiments of the present invention, lens distortion is a general term for the inherent perspective distortion of optical lenses, also known as distortion, which is mainly caused by the shape of camera lenses and photography technology. Distortion coefficients are important parameters that describe this distortion. The size of the intermediate image plane is S1, the size of the intermediate image plane S1, the field of view w, and the focal length f of the wide-angle imaging lens 201 c And the relationship between the lens distortion dist of the wide-angle imaging lens 201 satisfies formula (1):

[0075] S1=f c ×tan(w)×(1-dist)(1).

[0076] According to some embodiments of the present invention, the size of the intermediate image plane may affect the size selection of the field stop 4 , the filter 5 , the relay telecentric imaging lens assembly 6 , and the camera 7 .

[0077] According to some alternative embodiments of the present invention, the size S1 of the intermediate image plane satisfies 20 mm. <S1<60mm。

[0078] According to some alternative embodiments of the present invention, the field of view w of the wide-angle imaging lens 201 is 130°, and the focal length f of the wide-angle imaging lens 201 is c is 23 mm. At this time, the size S1 of the intermediate image plane satisfies formula (2):

[0079] S1=2×f c ×tan(65°)×(1-dist)(2).

[0080] According to some embodiments of the present invention, the lens distortion dist of the wide-angle imaging lens 201 is 0.5.

[0081] According to some embodiments of the present invention, the focal lengths, apertures Dc, and field angles of multiple wide-angle imaging lenses 201 are equal, and the multiple wide-angle imaging lenses 201 are all achromatic wide-angle imaging lenses, that is, the initial airglow beams of different spectral bands have no effect on the focal length and other parameters of each wide-angle imaging lens, thereby achieving exactly the same imaging observation area for the initial airglow beam.

[0082] According to some embodiments of the present invention, the imaging bands of the plurality of wide-angle imaging lenses 201 are different, so that the airglow spectrum imaging system can detect and image airglow spectrum signals in as many different spectrum bands as possible.

[0083] According to some embodiments of the present invention, the first convex lens 601 is adapted to focus the telecentric light beam to form a focused light beam; and the second convex lens 602 is adapted to image the focused light beam. Meet 100mm< <300 mm, focal length of the second convex lens 602 Meet 10mm< <100 mm, focal length of the first convex lens 601 Greater than the focal length of the second convex lens 602 .

[0084] According to some alternative embodiments of the present invention, the focal length of the first convex lens 601 is and the focal length of the second convex lens 602 The relationship between .

[0085] Figure 2 A schematic diagram showing the arrangement of multiple aperture units of a relay telecentric imaging lens assembly in an airglow spectral imaging system according to an embodiment of the present invention is shown.

[0086] According to some embodiments of the present invention, Figure 2 As shown, the arrangement of the relay telecentric imaging lens assembly 6 is the same as the arrangement of the multiple wide-angle imaging lenses 201, and they are all arranged in a centrally symmetrical manner on the projection surface along the central axis 8 of the airglow spectrum imaging system. The aperture unit of the relay telecentric imaging lens assembly 6 includes a first aperture unit a, a second aperture unit b, a third aperture unit c and a fourth aperture unit d, a total of four aperture units, and the four aperture units correspond to the four wide-angle imaging lenses 201 one by one.

[0087] According to some embodiments of the present invention, the first convex lens 601 and the second convex lens 602 included in the relay telecentric imaging lens assembly 6 are both telecentric lenses, and the position setting between the first convex lens 601 and the second convex lens 602 satisfies the characteristics of the relay lens, so the relay telecentric imaging lens assembly 6 combines the characteristics of the relay lens and the telecentric lens. The relay lens can transmit the image formed by the front wide-angle lens (i.e., the imaging lens assembly 2) to the photosensitive surface of the camera 7, and the telecentric lens can improve the consistency of the incident angle of the corrected telecentric light beam incident on the photosensitive surface of the camera 7 at each field of view, thereby improving the consistency of imaging illumination. Therefore, the relay telecentric lens assembly 6 can not only transmit the image formed by the imaging lens assembly 2 to the photosensitive surface of the camera 7, but also change the incident angle of the corrected telecentric light beam incident on the photosensitive surface of the camera 7, thereby improving the resolution of multiple images captured by the camera 7.

[0088] According to some embodiments of the present invention, the imaging illuminance uniformity refers to the deviation of the received energy of each pixel in the photosensitive surface position of the camera 7 from the uniform intensity light source on the object side during the airglow spectral imaging process. Improving the imaging illuminance uniformity is beneficial to improving the data calculation accuracy of the final airglow imaging system, thereby improving the time resolution of the airglow beam imaging.

[0089] According to some embodiments of the present invention, the number of the filters 5 is the same as that of the wide-angle imaging lenses and is four, and the filters 5 are all narrow-band filters.

[0090] According to some alternative embodiments of the present invention, the central wavelengths of the four filters 5 are preferably 1521 nm, 1523.7 nm, 1542.8 nm, and 1532.5 nm.

[0091] According to some embodiments of the present invention, the clear aperture D of the filter 5 f satisfies 24 mm < D f < 102 mm. Since the filters 5 are all narrow-band filters, the bandwidths of each filter 5 are equal.

[0092] According to some embodiments of the present invention, by setting the central wavelengths of each filter 5 to be different, and the central wavelengths of the four filters 5 are 1521 nm, 1523.7 nm, 1542.8 nm, and 1532.5 nm respectively. Since the central wavelengths of the four filters 5 are all in the infrared spectral region, which is a band where the atmospheric airglow radiation is relatively significant, it is possible to invert the temperature of the airglow beam for detecting the same target atmosphere, so that an airglow temperature imaging map can be drawn and obtained.

[0093] According to some alternative embodiments of the present invention, the bandwidth of each filter 5 is 2 nm.

[0094] According to some embodiments of the present invention, the number of the field stops 4 is the same as that of the wide-angle imaging lenses 201 and is four, and the shape of the field stops 4 is rectangular to improve the utilization rate of the pixel size of the camera 7.

[0095] Figure 3 Shows an enlarged view of the structure of the spherical window in the airglow spectral imaging system according to an embodiment of the present invention.

[0096] According to some embodiments of the present invention, the aperture D of the spherical window 1 satisfies 100 mm < D < 300 mm, and the relationship between the thickness t of the spherical window 1 and the aperture D of the spherical window 1 satisfies 10 < D / t < 30.

[0097] According to some embodiments of the present invention, as Figure 3As shown, the spherical center angle α of the spherical window 1 satisfies 150°≤α≤180°, and the material of the spherical window 1 includes any one of optical glasses such as quartz, H-K9L, or other resin materials.

[0098] According to some alternative embodiments of the present invention, the spherical center angle α of the spherical window 1 is 160°, and the material of the spherical window 1 is preferably H-K9L optical glass.

[0099] According to some embodiments of the present invention, the thickness t of the spherical window 1 is the distance between the incident end face 9 and the exit end face 10, the initial gas glow light beam is incident from the incident end face 9 and exits from the exit end face 10, and the center of the incident end face 9 coincides with the center of the exit end face 10; the aperture D of the spherical window 1 is the diameter of the incident end face 9.

[0100] According to some embodiments of the present invention, a spherical window 1 is provided to protect the imaging lens assembly 2 from environmental pollution. The airglow spectral imaging system is not affected and at the same time has the functions of being waterproof, insect-proof, and easy to clean, thereby reducing the maintenance cost of the airglow spectral imaging system.

[0101] According to some embodiments of the present invention, the focal length F of the field lens 3 w Satisfy F w >20mm, the field lens 3 converts the airglow imaging beam into a telecentric beam and corrects the telecentric beam to reduce the angular deviation of the corrected telecentric beam incident on the filter 5.

[0102] According to some embodiments of the present invention, the field lens 3 is arranged to convert the airglow imaging beam into a telecentric beam, so that the angles of the telecentric beams of each field of view entering the optical filter 5 are consistent. The arrangement of the field lens 3 is beneficial to the consistency of the divergence angles of the telecentric beams of each field of view angle, reduces the divergence angle deviation of the output beams of each field of view angle, improves the uniformity of the incident angles of the beams of each field of view, and thus improves the consistency of the spectral bandwidth of each field of view angle passing through the optical filter 5.

[0103] According to some embodiments of the present invention, the relay telecentric imaging lens assembly 6 images the telecentric light beam corrected by the field lens 3 onto the photosensitive surface of the camera 7. The relay telecentric imaging lens assembly 6 includes two lenses, a first convex lens 601 and a second convex lens 602. By providing the first convex lens 601 and the second convex lens 602, the illumination uniformity of the imaging surface of the camera 7 is improved.

[0104] According to some alternative embodiments of the present invention, the focal length F of the field lens 3 is w It is 26mm.

[0105] According to some alternative embodiments of the present invention, the camera 7 comprises an area array camera, and the length of the area array camera is L and the width is N, wherein L>10 mm and N>10 mm.

[0106] Figure 4 A schematic diagram of imaging distribution of a camera photosensitive surface in an airglow spectrum imaging system according to an embodiment of the present invention is shown.

[0107] According to some embodiments of the present invention, Figure 4 As shown, the imaging distribution of the photosensitive surface of the camera 7 in the airglow spectrum imaging system corresponds one-to-one to the four wide-angle imaging lenses 201 and the four aperture units of the relay telecentric imaging lens assembly 6, that is, the first image 701 corresponds to the first aperture unit a of the relay telecentric imaging lens assembly 6, the second image 702 corresponds to the second aperture unit b of the relay telecentric imaging lens assembly 6, the third image 703 corresponds to the third aperture unit c of the relay telecentric imaging lens assembly 6, and the fourth image 704 corresponds to the fourth aperture unit d of the relay telecentric imaging lens assembly 6.

[0108] According to some embodiments of the present invention, by arranging a plurality of wide-angle imaging lenses 201, four aperture units of the relay telecentric imaging lens assembly 6, and the imaging distribution of the photosensitive surface of the camera 7 in one-to-one correspondence, overlapping of light beams incident on the photosensitive surface of the camera 7 is avoided, overlapping of multiple images captured by the camera 7 is avoided, and simultaneous imaging of multiple spectral bands of the airglow beam (i.e., the initial airglow beam) generated by the atmosphere is achieved, thereby improving the resolution of the airglow beam imaging.

[0109] Figure 5 A distortion curve diagram of imaging of a single aperture unit in a relay telecentric imaging lens assembly in an airglow spectral imaging system according to an embodiment of the present invention is shown.

[0110] According to some embodiments of the present invention, Figure 5 As shown in the figure, the distortion curve of a single aperture unit imaging shows that the image distortion changes with the field of view position, where the ordinate of the distortion curve represents the half-field of view angle position, that is, the distance from a point in the image to the center of the image formed by the camera (usually expressed in degrees or millimeters, and half of the value is taken to represent the half field of view); the abscissa of the distortion curve represents the distortion amount at the point, in percentage (%), indicating the degree of deviation between the actual image height and the ideal image height. By analyzing the distortion curve, the distortion characteristics of the above-mentioned airglow spectral imaging system at different field of view positions can be understood, and corresponding measures can be taken in time for correction and optimization, thereby improving the accuracy and resolution of airglow beam imaging.

[0111] According to some embodiments of the present invention, the focal length F of the above-mentioned airglow spectrum imaging system satisfies F=f c ×m; where f c is the focal length of the wide-angle imaging lens, m is the imaging magnification of the relay telecentric imaging lens assembly 6, and m satisfies 0.1 <m<0.5。

[0112] According to some alternative embodiments of the present invention, the imaging magnification m of the relay telecentric imaging lens assembly 6 is 0.25 times.

[0113] According to some embodiments of the present invention, the size of each image of the photosensitive surface of the camera 7 is h, and h satisfies formula (3):

[0114] h = tan(w) × f c ×(1-dist) ×m×(1-distc)(3),

[0115] Wherein distc is the lens distortion of the relay telecentric imaging lens assembly 6. The imaging distortion of the above-mentioned airglow spectral imaging system is (1-dist)×(1-distc)<60%. The value of the F number (F#) of the above-mentioned airglow spectral imaging system is set to F#<1.5, which is a large-flux aperture parameter. The relationship between the F number and the entrance pupil size Dp of each aperture unit of the above-mentioned airglow spectral imaging system satisfies Dp=F / F#. The F number is the ratio of the focal length F of the lens to the pupil diameter, that is, the F number satisfies F#=F / D.

[0116] According to some alternative embodiments of the present invention, the F number of the above-mentioned airglow spectrum imaging system is 1.3.

[0117] According to some embodiments of the present invention, the single-pixel luminous flux Φ of the system satisfies formula (4):

[0118] (4),

[0119] Where B is the brightness of the object after atmospheric attenuation, and π is approximately 3.1415926.

[0120] According to some embodiments of the present invention, the pixel size of the camera 7 is x, corresponding to the upper atmosphere space size S c , satisfying formula (5):

[0121] (5),

[0122] Where L w is the altitude of the atmosphere corresponding to the detected airglow beam.

[0123] According to some alternative embodiments of the present invention, the pixel size of the camera 7 is set to 15 μm, the focal length F of the above-mentioned airglow spectrum imaging system is set to 4.5 mm, and the detection object height L w is 87 km, so S is calculated c It is 290m.

[0124] Figure 6 shows the wave shape of a gravity wave with a wavelength of 1.5 km according to an embodiment of the present invention; Figure 7The imaging resolution diagram of the wave shape of a gravity wave with a wavelength of 1.5 km after passing through the airglow spectrum imaging system according to an embodiment of the present invention is shown.

[0125] According to some embodiments of the present invention, Figure 6 The wavelength is 1.5 km (L wav =1.5km) of gravity waves, Figure 7 This is a waveform simulation diagram of the wave shape of a gravity wave with a wavelength of 1.5 km after passing through the airglow spectrum imaging system. Figure 6 and Figure 7 It can be seen that the above-mentioned airglow spectrum imaging system is able to distinguish the wave shape of gravity waves with a wavelength of 1.5 km, and has a high waveform resolving power and a high waveform resolution for gravity waves with a wavelength of 1.5 km.

[0126] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present invention may be combined and / or combined in various ways, even if such combinations and / or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments and / or claims of the present invention may be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All of these combinations and / or combinations fall within the scope of the present invention.

[0127] The embodiments of the present invention are described above. However, these embodiments are only for the purpose of illustration, and are not intended to limit the scope of the present invention. Although each embodiment is described above, it does not mean that the measures in each embodiment cannot be used in combination. The scope of the present invention is defined by the attached claims and their equivalents. Without departing from the scope of the present invention, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. An airglow spectral imaging system, characterized in that: Comprising: A spherical window, adapted to pass through an initial airglow beam generated by the atmosphere; An imaging lens assembly, adapted to image multiple spectral bands of the initial airglow beam simultaneously and output multiple airglow imaging beams; wherein, the imaging lens assembly includes a plurality of wide-angle imaging lenses, the number of the plurality of wide-angle imaging lenses is four, and the plurality of wide-angle imaging lenses image four spectral bands of the initial airglow beam respectively; A field lens, adapted to convert the airglow imaging beam into a telecentric beam and correct the telecentric beam; A relay telecentric imaging lens assembly, adapted to image the corrected telecentric beam; A camera, adapted to collect a plurality of images generated by the relay telecentric imaging lens assembly, and the plurality of images respectively correspond to the multiple spectral bands of the initial airglow beam; and A filter, adapted to allow a beam with a specific wavelength in the corrected telecentric beam to pass through, and the number of the filters is four; The relay telecentric imaging lens assembly includes a first convex lens and a second convex lens, and the focal length of the first convex lens is and the second convex lens The relationship between the focal lengths satisfies: .

2. The airglow spectrum imaging system according to claim 1, characterized in that: The wide-angle imaging lens is a retrofocus type imaging lens, wherein, the plurality of wide-angle imaging lenses are arranged in central symmetry on a projection plane along the central axis direction of the airglow spectral imaging system, and the optical axes of the plurality of wide-angle imaging lenses are all parallel to the central axis.

3. The airglow spectrum imaging system according to claim 1, characterized in that: The first convex lens is adapted to focus the telecentric beam to form a focused beam; and the second convex lens is adapted to image the focused beam; Among them, the focal length of the first convex lens is Meet 100mm< <300mm, the focal length of the second convex lens Meet 10mm< <100mm.

4. The airglow spectrum imaging system according to claim 2, characterized in that: Further comprising: A field stop, adapted to filter out beams outside the required field of view angle of the airglow spectral imaging system to prevent the plurality of images collected by the camera from overlapping.

5. The airglow spectrum imaging system according to claim 1, characterized in that: The filters are all narrow-band filters.

6. The airglow spectrum imaging system according to claim 4, characterized in that: The number of the field stops is the same as the number of the wide-angle imaging lenses and is four, and the shape of the field stop is rectangular to improve the utilization rate of the pixel size of the camera.

7. The airglow spectrum imaging system according to claim 1, characterized in that: The aperture D of the spherical window satisfies 100mm < D < 300mm, and the relationship between the thickness t of the spherical window and the aperture D of the spherical window satisfies 10 < D / t < 30.

8. The airglow spectrum imaging system according to claim 2, characterized in that: The focal length of the wide-angle imaging lens is f c Satisfying 10mm < f c < 40mm, the field of view angle w of the wide-angle imaging lens satisfies 120° < w < 180°, and the imaging wavelength wav of the wide-angle imaging lens satisfies 1500nm < wav < 1600nm.

9. The airglow spectrum imaging system according to claim 4, characterized in that: The focal length F of the field lens w Satisfy F w >20mm, the field lens converts the airglow imaging beam into a telecentric beam and corrects the telecentric beam to reduce the angular deviation of the corrected telecentric beam incident on the filter.

10. The airglow spectrum imaging system according to claim 2, characterized in that: The focal length F of the airglow spectrum imaging system satisfies F=f c ×m; Among them, f c is the focal length of the wide-angle imaging lens, m is the imaging magnification of the relay telecentric imaging lens assembly, and m satisfies 0.1 <m<0.5。

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