High-resolution large-view-field optical lens for aerial camera

Abstract

The invention relates to a high-resolution large-view-field optical lens for an aerial camera, and belongs to the technical field of photoelectric instruments. Comprising window glass (1), an objective lens assembly, a reflector (12) and a CMOS detector. The objective lens assembly comprises a first lens (2), a second lens (3), a third lens (4), a fourth lens (5), a diaphragm (6), a fifth lens (7), a sixth lens (8), a seventh lens (9), an eighth lens (10) and a ninth lens (11) which are sequentially and coaxially arranged from front to back in the light path direction. The window glass (1) and the first lens (2) are coaxially arranged, and the window glass (1) is arranged in front of the first lens (2); and the reflector (12) is obliquely fixed on the optical axis at a certain angle and is arranged behind the ninth lens (11). The optical system has the advantages of being simple in design, large in field angle, high in resolution, small in size and high in reliability.

Description

Technical Field

[0001] The invention belongs to the technical field of optoelectronic instruments, and in particular relates to a high-resolution and large-field optical lens for an aerial camera. Background Art

[0002] The basic structure of the optical lens of an aerial camera is similar to that of an ordinary photographic lens. Its characteristics are that the aberration correction is more stringent than that of an ordinary lens, and it has extremely high resolution and contrast. It is difficult to design and requires the ability to adapt to various climate and light conditions. It is mostly used in military and meteorological fields. As the application of aerial cameras becomes more and more extensive, the requirements for the resolution and large field of view of aerial cameras are getting higher and higher. With the development of domestic chip technology, the pixel size of imaging chips is getting smaller and smaller, and camera lenses can be designed with higher and higher resolution. However, due to the limitation of process size, the size of CMOS image sensors cannot be made large according to the requirements of field of view, so the size of CMOS image sensors has become the main factor limiting the field of view of cameras. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] The technical problem to be solved by the present invention is to provide a high-resolution and large-field-of-view optical lens for an aerial camera, which has the advantages of large field of view, small size and simple optical system.

[0005] (II) Technical solution

[0006] In order to solve the above technical problems, the present invention provides a high-resolution and large-field optical lens for an aerial camera, comprising: a window glass 1, an objective lens assembly, a reflector 12, and a CMOS detector;

[0007] The objective lens assembly comprises: a first lens 2, a second lens 3, a third lens 4, a fourth lens 5, a stop 6, a fifth lens 7, a sixth lens 8, a seventh lens 9, an eighth lens 10, and a ninth lens 11, which are coaxially arranged in sequence from front to back along the optical path direction;

[0008] The window glass 1 is coaxially arranged with the first lens 2 and arranged in front of the first lens 2;

[0009] The reflector 12 is fixed on the optical axis at a certain angle and is placed behind the ninth lens 11;

[0010] The CMOS detectors are provided with two, which are respectively denoted as a first CMOS detector 13 and a second CMOS detector 14. The first CMOS detector 13 is coaxially arranged with the optical axis behind the reflector 12, and the second CMOS detector 14 is perpendicular to the optical axis and arranged below the reflector 12.

[0011] The external scene light is split by the reflector 12 onto two CMOS detectors, and the two CMOS detectors are spliced ​​to form an image.

[0012] The aperture 6 is arranged at the center of the optical axis.

[0013] Among them, the pixel size of the two CMOS detectors is 4.6μm, the number of pixels on the image plane is 8424×6032, the focal length is designed to be 126mm, 632.8nm is selected as the central wavelength of the system design, the relative aperture is 6, and the field of view angle is ≥35°, the pixel resolution is ≤0.19m, and the optical imaging at a shooting height of 5000m is achieved.

[0014] Among them, the external scene light is split by a reflector and projected onto two detectors, which expands the field of view by 2 times, that is, the field of view angle is ≥35°.

[0015] (III) Beneficial effects

[0016] Compared with the prior art, the present invention has the following beneficial effects: using a domestically produced CMOS chip with a small pixel size (4.6um), and through optical design, realizing a high-resolution lens with a resolution of 108 (lp / mm);

[0017] The optical lens adopts a double Gaussian lens structure as the basic form, and designs a coaxial transmission optical path system. The external scene light is split by a reflector and projected onto two detectors, realizing the design of an optical lens that expands the field of view by 2 times (field of view angle ≥ 35°). BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a diagram of the structure of the optical lens of the present invention;

[0019] Figure 2 The double Gauss lens design result of the optical lens of the present invention;

[0020] Figure 3 It is the vignetting diagram of the optical lens of the present invention;

[0021] Figure 4 Designing a transmission function for the optical lens of the present invention;

[0022] Figure 5 This is the field curvature and distortion diagram of the lens used in this invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, content, and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the accompanying drawings and examples.

[0024] This embodiment provides a high-resolution and large-field optical lens for an aerial camera, comprising: a window glass 1, an objective lens assembly, a reflector 12, and a CMOS detector;

[0025] The objective lens assembly comprises: a first lens 2, a second lens 3, a third lens 4, a fourth lens 5, a stop 6, a fifth lens 7, a sixth lens 8, a seventh lens 9, an eighth lens 10, and a ninth lens 11, which are coaxially arranged in sequence from front to back along the optical path direction;

[0026] The window glass 1 is coaxially arranged with the first lens 2 and arranged in front of the first lens 2;

[0027] The reflector 12 is fixed on the optical axis at a certain angle and is placed behind the ninth lens 11;

[0028] The CMOS detectors are provided with two, which are respectively denoted as a first CMOS detector 13 and a second CMOS detector 14. The first CMOS detector 13 is coaxially arranged with the optical axis behind the reflector 12, and the second CMOS detector 14 is perpendicular to the optical axis and arranged below the reflector 12.

[0029] The external scene light is split by the reflector 12 onto two CMOS detectors, and the two CMOS detectors are spliced ​​to form an image.

[0030] The aperture 6 is arranged at the center of the optical axis.

[0031] Among them, the pixel size of the two CMOS detectors is 4.6μm, the number of pixels on the image plane is 8424×6032, the focal length is designed to be 126mm, 632.8nm is selected as the central wavelength of the system design, the relative aperture is 6, and the field of view angle is ≥35°, the pixel resolution is ≤0.19m, and the optical imaging at a shooting height of 5000m is achieved.

[0032] Among them, the external scene light is split by a reflector and projected onto two detectors, which expands the field of view by 2 times, that is, the field of view angle is ≥35°.

[0033] The optical lens adopts a double Gaussian lens structure as the basic form and is optimized on this basis. The double Gaussian objective is one of the basic forms of aberration-free objective. The optical elements of this objective are centered on the aperture to form an almost symmetrical structural layout, which can better correct phase aberration within a large aperture and medium field of view.

[0034] The optical lens has a vignetting coefficient of K = 1 in the full field of view, which meets the system design requirements. According to the wavelength weight design, the optical system design transfer function average transfer function MTF = 0.43 (108lp / mm), the optical lens uses two detector devices for splicing, considering 152 overlapping pixels, the actual focal length is about 76.8mm, and the corresponding ground width is about 3047m (H = 5km).

[0035] Distortion is a parameter often mentioned in optical systems and is one of the important factors that limit the accuracy of optical measurements. It is the degree of distortion of the image formed by the optical system on the object relative to the object itself. It only causes the deformation of the image and has no effect on the clarity of the image. The system distortion is less than 0.3%, and the system distortion meets the system use requirements. Field curvature reflects the degree of curvature of the image plane of the optical system. The deviation of the object from the ideal focus after passing through the optical system is within the semi-focal depth, which meets the system use requirements.

[0036] Through parameter selection and design, the technical indicators of the optical lens are shown in the table. The designed optical lens achieves the characteristics of high resolution, large field of view, small size, light weight, and wide applicability.

[0037] Table 1 Optical system design indicators

[0038]

[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high-resolution and large-field-of-view optical lens for an aerial camera, characterized in that: include: Window glass (1), objective lens assembly, reflector (12), CMOS detector; The objective lens assembly comprises: a first lens (2), a second lens (3), a third lens (4), a fourth lens (5), a stop (6), a fifth lens (7), a sixth lens (8), a seventh lens (9), an eighth lens (10), and a ninth lens (11) which are coaxially arranged in sequence from front to back along the optical path; The window glass (1) is coaxially arranged with the first lens (2) and is arranged in front of the first lens (2); The reflector (12) is fixed on the optical axis at a certain angle and is placed behind the ninth lens (11); The CMOS detectors are provided with two, respectively denoted as a first CMOS detector (13) and a second CMOS detector (14); the first CMOS detector (13) is arranged coaxially with the optical axis behind the reflector (12); and the second CMOS detector (14) is arranged perpendicular to the optical axis below the reflector (12); The external scene light is split by a reflector (12) onto two CMOS detectors, and an image is formed by splicing the two CMOS detectors.

2. The high-resolution and large-field-of-view optical lens for an aerial camera according to claim 1, characterized in that: The aperture (6) is arranged at the center of the optical axis.

3. The high-resolution and large-field-of-view optical lens for an aerial camera according to claim 1, characterized in that: The pixel size of the two CMOS detectors is 4.6 μm, the number of image plane pixels is 8424×6032, and the focal length is designed to be 126 mm.

4. The high-resolution and large-field-of-view optical lens for an aerial camera according to claim 1, characterized in that: The external scene light is split by a reflector and projected onto two detectors, which doubles the field of view, that is, the field of view is ≥35°.

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