A high-resolution compact dual-channel remote sensing optical system

Abstract

The application relates to a high-resolution compact double-channel remote sensing optical system, relates to the technical field of space optical remote sensing loads, and solves the defects of the existing visible light optical system and long-wave infrared optical system when used alone. The application adopts a coaxial catadioptric system, comprises a visible light imaging channel and a long-wave infrared imaging channel, and the two channels comprise a shared light path; the long-wave infrared imaging channel comprises a first lens group, a fifth mirror and a second lens group; light rays are imaged on a visible light imaging target surface after passing through the shared light path and the front surface of a first beam splitter; the light rays are sequentially imaged on a long-wave infrared imaging target surface after passing through the shared light path, being transmitted by the first beam splitter, passing through the first lens group, the fifth mirror and the second lens group. The new type integrates the visible light imaging channel and the long-wave infrared imaging channel in one system, improves the working ability of the optical system under all-weather and complex environments, and provides hardware support for obtaining high accuracy and multi-level images under complex environments.

Description

Technical Field

[0001] This utility model relates to the field of space optical remote sensing payload technology, specifically to a high-resolution compact dual-channel remote sensing optical system. Background Technology

[0002] One of the core components of space optical remote sensing payloads is the optical system. Visible light optical systems and long-wave infrared optical systems are currently the most widely used optical systems in the field of space remote sensing. A standalone visible light optical system can achieve high spatial resolution, provide intuitive information, and offer rich detail, but its fatal weakness is its susceptibility to lighting conditions, making it unable to operate at night and unable to penetrate clouds or fog. A standalone long-wave infrared optical system can operate around the clock, detect thermal targets, and has a certain degree of penetration capability, but its main drawback is that its spatial resolution is usually lower than that of a visible light system of the same aperture, resulting in images lacking color and texture detail, making accurate target identification difficult.

[0003] Therefore, integrating visible light and long-wave infrared optical systems into a single common-path system successfully combines the advantages of both types of cameras and overcomes the inherent defects of discrete systems. This provides a powerful hardware platform for achieving higher-level and more intelligent remote sensing detection and is an important direction for the development of space optical remote sensing payload technology now and in the future. Utility Model Content

[0004] This invention addresses the shortcomings of existing visible light optical systems and long-wave infrared optical systems when used alone, by providing a high-resolution, compact, dual-channel remote sensing optical system.

[0005] A high-resolution, compact, dual-channel remote sensing optical system, wherein the optical system adopts a coaxial catadioptric system and includes a visible light imaging channel and a long-wave infrared imaging channel;

[0006] The visible light imaging channel and the long-wave infrared imaging channel share a common optical path;

[0007] The shared optical path includes a first reflector, a second reflector, a third reflector, a fourth reflector, and a first beam splitter;

[0008] The long-wave infrared imaging channel also includes a first lens group, a fifth reflecting mirror, and a second lens group;

[0009] The light rays are imaged on the visible light imaging target surface after passing through the first reflecting mirror, the second reflecting mirror, the third reflecting mirror, the fourth reflecting mirror, and the front surface of the first beam splitter.

[0010] After being transmitted through the first, second, third, and fourth reflecting mirrors and the first beam splitter, the light rays are sequentially imaged on the long-wave infrared imaging target surface by the first lens group, the fifth reflecting mirror, and the second lens group.

[0011] The first lens group includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens;

[0012] The second lens group includes a sixth lens, a seventh lens, and an infrared window lens;

[0013] The focal length of the first reflector is between 940mm and 960mm, the focal length of the second reflector is between -220mm and -240mm, and the focal length of the third reflector is between 300mm and 320mm.

[0014] The focal length of the first lens is between 70mm and 90mm, the focal length of the second lens is between -140mm and -160mm, the focal length of the third lens is between 2100mm and 2200mm, the focal length of the fourth lens is between -120mm and -140mm, and the focal length of the fifth lens is between 80mm and 100mm.

[0015] The focal length of the sixth lens is between -440mm and -460mm, and the focal length of the seventh lens is between 40mm and 60mm.

[0016] The beneficial effects of this utility model are as follows: The optical system described in this utility model integrates the two into a common optical path optical system by selecting a suitable structure, which enhances the working ability of the remote sensing optical system in all weather and complex environments, and makes the optical system have the advantages of compactness, lightweight, high contrast and high resolution.

[0017] 1. By folding the light path multiple times through a plane mirror, the overall envelope size of the optical system is shortened, resulting in a compact structure and achieving compact optical lenses.

[0018] 2. The dual-channel optical system uses four mirrors and one beam splitter, which reduces the number of optical components, greatly reduces the difficulty of assembly and adjustment, and also makes the overall structure more compact, which is conducive to the compactness and weight reduction of optical lenses.

[0019] 3. The visible light imaging channel can resolve a 0.5m object at a distance of 500km and capture an image with a width greater than 11km. The long-wave infrared imaging channel can resolve a 12m object at a distance of 500km and capture an image with a width greater than 11km, achieving wide-swath, high-resolution imaging and capturing more and finer image details.

[0020] 4. Integrating the visible light imaging channel and the long-wave infrared imaging channel into one system can avoid the shortcomings of using the two optical systems separately, improve the working ability of the optical system in all weather and complex environments, and provide hardware support for obtaining high-accuracy, multi-layered images in complex environments. Attached Figure Description

[0021] Figure 1 This is an optical path diagram of a high-resolution compact dual-channel remote sensing optical system according to the present invention.

[0022] Figure 2 The visible light imaging channel dot plot shows that the size of the blur spot is smaller than the pixel size of the imaging target surface throughout the entire field of view, resulting in good imaging quality.

[0023] Figure 3 The image shows a long-wave infrared imaging channel dot plot. The size of the blur spot is smaller than the pixel size of the imaging target surface throughout the entire field of view, resulting in good imaging quality.

[0024] Figure 4 The MTF curve for the visible light imaging channel shows that at the cutoff frequency, the MTF curve of this system is greater than 0.34, which is close to the diffraction limit.

[0025] Figure 5 The MTF curve for the long-wave infrared imaging channel is shown. At the cutoff frequency, the MTF curve of this system is greater than 0.368.

[0026] In the diagram: L1, first reflecting mirror; L2, second reflecting mirror; L3, third reflecting mirror; L4, fourth reflecting mirror; L5, first beam splitter; L6, first lens; L7, second lens; L8, third lens; L9, fourth lens; L10, fifth lens; L11, fifth reflecting mirror; L12, sixth lens; L13, seventh lens; L14, infrared window lens; S1, visible light imaging target surface; S2, long-wave infrared imaging target surface. Detailed Implementation

[0027] Specific Implementation Method 1: Combination Figure 1 This embodiment describes a high-resolution compact dual-channel remote sensing optical system. The optical system has a coaxial catadioptric system structure and two imaging channels: a visible light imaging channel and a long-wave infrared imaging channel.

[0028] The dual-channel remote sensing optical system includes an imaging target surface, a mirror group for reflecting light, and a lens group for refracting light. The first mirror L1, the second mirror L2, the third mirror L3, the fourth mirror L4, and the first beam splitter L5 share the same optical path for the visible light imaging channel and the long-wave infrared imaging channel.

[0029] The light rays of the visible light imaging channel pass sequentially through the front surfaces of the first reflecting mirror L1, the second reflecting mirror L2, the third reflecting mirror L3, the fourth reflecting mirror L4, and the first beam splitter L5, and finally form an image on the visible light imaging target surface S1.

[0030] The light rays of the long-wave infrared imaging channel pass sequentially through the first reflecting mirror L1, the second reflecting mirror L2, the third reflecting mirror L3, the fourth reflecting mirror L4, the first beam splitter L5, the first lens group, the fifth reflecting mirror L11, and the second lens group, and finally form an image on the long-wave infrared imaging target surface S2.

[0031] In this embodiment, the first lens group includes a first lens L6, a second lens L7, a third lens L8, a fourth lens L9, and a fifth lens L10; the second lens group includes a sixth lens L12, a seventh lens L13, and an infrared window lens L14.

[0032] In this embodiment, the first beam splitter L5 is a dual-plane lens, whose front surface reflects light in the 450nm~800nm ​​spectral range and transmits light in the 8μm~10μm spectral range.

[0033] In this embodiment, the focal length of the first reflector L1 is between 940mm and 960mm, the focal length of the second reflector L2 is between -220mm and -240mm, the focal length of the third reflector L3 is between 300mm and 320mm, and the fourth reflector L4 and the fifth reflector L11 are planar.

[0034] In this embodiment, the focal length of the first lens L6 is between 70mm and 90mm, the focal length of the second lens L7 is between -140mm and -160mm, the focal length of the third lens L8 is between 2100mm and 2200mm, the focal length of the fourth lens L9 is between -120mm and -140mm, the focal length of the fifth lens L10 is between 80mm and 100mm, the focal length of the sixth lens L12 is between -440mm and -460mm, and the focal length of the seventh lens L13 is between 40mm and 60mm.

[0035] In this embodiment, the thickness of the first lens L6 is between 10mm and 12mm, the thickness of the second lens L7 is between 9mm and 11mm, the thickness of the third lens L8 is between 9mm and 11mm, the thickness of the fourth lens L9 is between 6mm and 8mm, the thickness of the fifth lens L10 is between 9mm and 11mm, the thickness of the sixth lens L12 is between 15mm and 17mm, and the thickness of the seventh lens L13 is between 13mm and 15mm.

[0036] The infrared window lens L14 is a dual-plane lens with a thickness of 4mm.

[0037] In this embodiment, the air gap between the first reflector L1 and the second reflector L2 is between 760mm and 780mm; the air gap between the second reflector L2 and the third reflector L3 is between 1320mm and 1340mm; the air gap between the third reflector L3 and the fourth reflector L4 is between 380mm and 400mm; the air gap between the fourth reflector L4 and the first beam splitter L5 is between 80mm and 100mm; the air gap between the first beam splitter L5 and the visible light imaging target surface S1 is between 340mm and 370mm; the air gap between the first beam splitter L5 and the first lens L6 is between 40mm and 60mm; the air gap between the first lens L6 and the second lens L7 is between 14mm and 17mm; and the air gap between the second lens L7 and the third reflector L6 is between 14mm and 17mm. The air gap between lenses L8 is between 1mm and 3mm; the air gap between the third lens L8 and the fourth lens L9 is between 60mm and 70mm; the air gap between the fourth lens L9 and the fifth lens L10 is between 10mm and 12mm; the air gap between the fifth lens L10 and the fifth reflecting mirror L11 is between 40mm and 50mm; the air gap between the fifth reflecting mirror L11 and the sixth lens L12 is between 70mm and 80mm; the air gap between the sixth lens L12 and the seventh lens L13 is between 18mm and 22mm; the air gap between the seventh lens L13 and the infrared window lens L14 is between 15mm and 20mm; and the air gap between the infrared window lens L14 and the long-wave infrared imaging target surface S2 is between 35mm and 45mm.

[0038] In this embodiment, the pixel size of the visible light imaging target surface S1 is 7μm, and the pixel size of the long-wave infrared imaging target surface S2 is 20μm.

[0039] In this embodiment, the fourth reflecting mirror L4 has a rotation angle of 35° relative to the optical axis, the first beam splitter L5 has a rotation angle of 10° relative to the optical axis, and the fifth reflecting mirror L11 has a rotation angle of 59.2° relative to the optical axis.

[0040] In this embodiment, the visible light imaging channel has a focal length between 7400mm and 7600mm, an entrance pupil diameter of 700mm, a resolution of less than 0.5m at a distance of 500km, a field of view greater than 1.3° × 0.2°, a panchromatic imaging spectrum range between 450nm and 800nm, and an optical envelope size less than φ700mm × 1337mm. The long-wave infrared imaging channel has a focal length between 860mm and 900mm, an entrance pupil diameter of 700mm, a resolution of less than 12m at a distance of 500km, a field of view greater than 1.3° × 0.1°, a long-wave infrared imaging spectrum range between 8μm and 10μm, and an optical envelope size less than φ700mm × 1337mm.

[0041] Specific Implementation Method Two: Combination Figures 2 to 5 This embodiment describes the optimal parameters of each mirror in the high-resolution compact dual-channel remote sensing optical system described in Embodiment 1. The optical system is a coaxial catadioptric system with two imaging channels: a visible light imaging channel and a long-wave infrared imaging channel. The visible light imaging channel has a focal length of 7500mm, an entrance pupil diameter of 700mm, a resolution of 0.467m at a distance of 500km, a field of view of 1.3°×0.2°, a panchromatic imaging spectrum range between 450nm and 800nm, and an optical envelope size of φ700mm×1336.7mm. The long-wave infrared imaging channel has a focal length of 882.896mm, an entrance pupil diameter of 700mm, a resolution of 11.326m at a distance of 500km, a field of view of 1.3°×0.1°, a long-wave infrared imaging spectrum range between 8μm and 10μm, and an optical envelope size smaller than φ700mm×1336.7mm. Specifically as follows:

[0042] Visible light imaging channels are shown in Table 1:

[0043] Table 1

[0044]

[0045] The long-wave infrared imaging channels are shown in Table 2:

[0046] Table 2:

[0047]

[0048] like Figures 2 to 5 The image shown is the result of the imaging quality analysis of the optical system:

[0049] Figure 2 The middle image shows the visible light imaging channel dot plot. The size of the blur spot is smaller than the pixel size of the imaging target surface throughout the entire field of view, indicating good imaging quality. Figure 3 The image shows a long-wave infrared imaging channel dot plot. The size of the blur spot is smaller than the pixel size of the imaging target surface throughout the entire field of view, resulting in good imaging quality. Figure 4 The MTF curve for the visible light imaging channel shows that at the cutoff frequency, the MTF curve of this system is greater than 0.34, which is close to the diffraction limit. Figure 5 The MTF curve for the long-wave infrared imaging channel is shown. At the cutoff frequency, the MTF curve of this system is greater than 0.368.

[0050] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0051] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A high-resolution, compact, dual-channel remote sensing optical system, characterized by: The optical system adopts a coaxial catadioptric system, including a visible light imaging channel and a long-wave infrared imaging channel; The visible light imaging channel and the long-wave infrared imaging channel share a common optical path; The shared optical path includes a first reflector (L1), a second reflector (L2), a third reflector (L3), a fourth reflector (L4), and a first beam splitter (L5). The long-wave infrared imaging channel also includes a first lens group, a fifth reflecting mirror (L11), and a second lens group; After passing through the front surfaces of the first reflecting mirror (L1), the second reflecting mirror (L2), the third reflecting mirror (L3), the fourth reflecting mirror (L4), and the first beam splitter (L5), light is imaged on the visible light imaging target surface (S1). After being transmitted through the first reflecting mirror (L1), the second reflecting mirror (L2), the third reflecting mirror (L3), the fourth reflecting mirror (L4) and the first beam splitter (L5), the light rays are sequentially imaged on the long-wave infrared imaging target surface (S2) by the first lens group, the fifth reflecting mirror (L11) and the second lens group. The first lens group includes a first lens (L6), a second lens (L7), a third lens (L8), a fourth lens (L9), and a fifth lens (L10). The second lens group includes a sixth lens (L12), a seventh lens (L13), and an infrared window lens (L14). The focal length of the first reflector (L1) is between 940mm and 960mm, the focal length of the second reflector (L2) is between -220mm and -240mm, and the focal length of the third reflector (L3) is between 300mm and 320mm. The first lens (L6) has a focal length between 70mm and 90mm, the second lens (L7) has a focal length between -140mm and -160mm, the third lens (L8) has a focal length between 2100mm and 2200mm, the fourth lens (L9) has a focal length between -120mm and -140mm, and the fifth lens (L10) has a focal length between 80mm and 100mm. The sixth lens (L12) has a focal length between -440mm and -460mm, and the seventh lens (L13) has a focal length between 40mm and 60mm.

2. The high-resolution compact dual-channel remote sensing optical system according to claim 1, characterized in that: The first beam splitter (L5) is a dual-plane lens. Its front surface reflects light in the 450nm~800nm ​​spectral range and transmits light in the 8μm~10μm spectral range.

3. The high-resolution compact dual-channel remote sensing optical system according to claim 1, characterized in that: The thickness of the first lens (L6) is between 10mm and 12mm, the thickness of the second lens (L7) is between 9mm and 11mm, the thickness of the third lens (L8) is between 9mm and 11mm, the thickness of the fourth lens (L9) is between 6mm and 8mm, the thickness of the fifth lens (L10) is between 9mm and 11mm, the thickness of the sixth lens (L12) is between 15mm and 17mm, and the thickness of the seventh lens (L13) is between 13mm and 15mm.

4. The high-resolution compact dual-channel remote sensing optical system according to claim 1, characterized in that: The infrared window lens (L14) is a dual-plane lens with a thickness of 4mm.

5. The high-resolution compact dual-channel remote sensing optical system according to claim 1, characterized in that: The air gap between the first reflector (L1) and the second reflector (L2) is between 760mm and 780mm, the air gap between the second reflector (L2) and the third reflector (L3) is between 1320mm and 1340mm, the air gap between the third reflector (L3) and the fourth reflector (L4) is between 380mm and 400mm, the air gap between the fourth reflector (L4) and the first beam splitter (L5) is between 80mm and 100mm, and the air gap between the first beam splitter (L5) and the visible light imaging target (S1) is between 340mm and 370mm.

6. The high-resolution compact dual-channel remote sensing optical system according to claim 1, characterized in that: The air gap between the first beam splitter (L5) and the first lens (L6) is between 40mm and 60mm; the air gap between the first lens (L6) and the second lens (L7) is between 14mm and 17mm; the air gap between the second lens (L7) and the third lens (L8) is between 1mm and 3mm; the air gap between the third lens (L8) and the fourth lens (L9) is between 60mm and 70mm; the air gap between the fourth lens (L9) and the fifth lens (L10) is between 10mm and 12mm; and the air gap between the fifth lens (L10) is between 10mm and 12mm. The air gap between the fifth reflector (L11) and the sixth lens (L12) is between 40mm and 50mm, the air gap between the fifth reflector (L11) and the sixth lens (L12) is between 70mm and 80mm, the air gap between the sixth lens (L12) and the seventh lens (L13) is between 18mm and 22mm, the air gap between the seventh lens (L13) and the infrared window lens (L14) is between 15mm and 20mm, and the air gap between the infrared window lens (L14) and the long-wave infrared imaging target surface (S2) is between 35mm and 45mm.

7. A high-resolution, compact, dual-channel remote sensing optical system according to claim 1, characterized in that: The fourth reflector (L4) and the fifth reflector (L11) are planar; the fourth reflector (L4) has a rotation angle of 35° relative to the optical axis, the first beam splitter (L5) has a rotation angle of 10° relative to the optical axis, and the fifth reflector (L11) has a rotation angle of 59.2° relative to the optical axis.

8. A high-resolution compact dual-channel remote sensing optical system according to claim 1, characterized in that: The visible light imaging target surface (S1) has a pixel size of 7 μm, and the long-wave infrared imaging target surface (S2) has a pixel size of 20 μm.

9. A high-resolution, compact, dual-channel remote sensing optical system according to claim 1, characterized in that: The visible light imaging channel has a focal length between 7400mm and 7600mm, an entrance pupil diameter of 700mm, a resolution of less than 0.5m at a distance of 500km, a field of view greater than 1.3°×0.2°, a panchromatic imaging spectrum range between 450nm and 800nm, and an optical envelope size of less than φ700mm×1337mm.

10. A high-resolution, compact, dual-channel remote sensing optical system according to claim 1, characterized in that: The long-wave infrared imaging channel has a focal length between 860mm and 900mm, an entrance pupil diameter of 700mm, a resolution of less than 12m at a distance of 500km, a field of view greater than 1.3°×0.1°, a long-wave infrared imaging spectrum range between 8μm and 10μm, and an optical envelope size of less than φ700mm×1337mm.

Images