A cross-media snell window edge peripheral vision imaging optical system

Abstract

The application discloses a cross-medium Snell window edge peripheral vision imaging optical system, and belongs to the optical technical field. The system is sequentially composed of a pressure-resistant protection window G1, a light path folding mirror G2, a wedge-shaped mirror G3, a focusing lens group G4, a front fixed imaging group G5 and a rear fixed imaging group G6 from the object side. The system is adapted to a 2048*2048 high-resolution detector with a pixel size of 5.5 microns, and has a Snell window edge peripheral vision panoramic imaging function through a peripheral scanning mode. The application overcomes the technical bottleneck of the underwater air-to-Snell window edge peripheral vision imaging optical design, provides a static sealing panoramic scanning imaging and compact optical module, and provides a new solution for the underwater air-to-Snell window edge peripheral vision imaging detection of an underwater submarine.

Description

Technical Field

[0001] This invention belongs to the field of optical technology, and more specifically, relates to a transmedia Snell window edge panoramic imaging optical system. Background Technology

[0002] The imaging optical system for observing sea surface and aerial targets underwater through waves was proposed by Areté Corporation in the United States. It provides an effective way for underwater air detection and has greatly promoted the development of underwater air cross-media imaging technology. Addressing the problem of severe compression at the edge of the field of view, Areté designed an oblique panoramic imaging system aligned with the edge of the Snell window, which can obtain clear imaging results in calm water.

[0003] However, this system only has a limited field-of-view staring imaging capability and lacks panoramic imaging. To achieve panoramic imaging, multiple systems would need to be stitched together. Because the system is tilted, stitching together panoramic imaging would drastically increase the size and weight of the entire optical system, which is detrimental to the miniaturization of underwater submersible devices. Summary of the Invention

[0004] In response to the above-mentioned deficiencies or improvement needs of existing technologies, this invention proposes a cross-medium Snell window edge panoramic imaging optical system. This system has staring and panoramic scanning imaging functions, which significantly improves the detection performance of underwater vehicles.

[0005] To achieve the above objectives, the present invention provides a transmedium Snell window edge panoramic imaging optical system, comprising: a pressure-resistant protective window (G1), an optical path folding mirror (G2), a wedge mirror (G3), a focusing lens group (G4), a front fixed imaging group (G5), and a rear fixed imaging group (G6) arranged sequentially from the object side to the image side along the light direction, so as to realize underwater aerial Snell window edge staring imaging and panoramic scanning imaging.

[0006] In some optional implementations, when imaging underwater, the operating wavelength is 450nm to 700nm, the F# is 1.8, and the imaging field of view is: elevation not less than 50° to 90°, azimuth 360°, adapted to a 2048×2048, 5.5μm visible light detector.

[0007] In some optional implementations, the staring imaging detection field of view is not less than 40°×40°; the scanning panoramic imaging is achieved by a motor driving the optical path folding mirror (G2), wedge mirror (G3), focusing mirror group (G4), front fixed imaging group (G5) and rear fixed imaging group (G6) and detector assembly to rotate around the vertical axis.

[0008] In some alternative implementations, the pressure-resistant protection window (G1) is a spherical meniscus concentric hemispherical lens (L11) used for optical system aberration balance correction.

[0009] In some alternative implementations, the optical path deflector (G2) is a prism or a reflector that deflects the beam at the edge of the Snell window by 48.6°, so that the beam passes through the center of the lens group G2 to G6 and is incident directly onto the center of the detector target surface.

[0010] In some alternative implementations, the wedge mirror (G3) is used to correct water dispersion, improve longitudinal compression of the optical system, and enhance the imaging quality of the optical system.

[0011] In some alternative implementations, a focusing lens group (G4) that can move back and forth along the optical axis is used to compensate for part of the defocusing effect caused by water disturbance, so as to achieve focusing function for both near and far-distance imaging.

[0012] In some alternative implementations, during underwater air-to-air Snell window edge staring imaging, the imaging beam is incident from the air medium, passes through the water medium and is incident on the pressure-resistant protective window (G1). After being converged by the pressure-resistant protective window (G1), the beam continues to propagate backward. Through the optical path folding mirror (G2), the Snell window edge imaging beam is folded 48.6° and incident on the center of the wedge mirror (G3). After passing through the wedge mirror (G3), the beam is refracted in sequence by the focusing lens group (G4), the front fixed imaging group (G5), and the rear fixed imaging group (G6), and finally imaged on the detector target surface.

[0013] In some alternative implementations, during underwater airborne Snell window edge scanning panoramic imaging, the optical path folding mirror (G2), wedge mirror (G3), focusing mirror group (G4), front fixed imaging group (G5), rear fixed imaging group (G6), and detector group rotate 360° around the vertical axis of the optical system under motor drive to achieve panoramic time-sharing imaging.

[0014] In some alternative implementations, the anterior fixed imaging group (G5) includes a first lens (L51), a second lens (L52), and a third lens (L53);

[0015] The first lens (L51) is a meniscus lens with negative optical power; the second lens (L52) is a cemented doublet lens with positive optical power; and the third lens (L53) is a meniscus lens with positive optical power.

[0016] The post-fixed imaging group (G6) includes: a fourth lens (L61), a fifth lens (L62), and a sixth lens (L63);

[0017] The fourth lens (L61) is a cemented doublet with positive optical power, the fifth lens (L62) is a biconvex lens with positive optical power, and the sixth lens (L63) is a cemented doublet with positive optical power.

[0018] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0019] The cross-medium Snell window edge panoramic imaging optical system is primarily designed for imaging and detection of targets near the edge of the Snell cone in the near-horizontal plane. It has overcome key technologies such as underwater panoramic imaging of near-horizontal targets in the Snell cone edge region, water dispersion compensation, and conformal dome design. This results in a miniaturized design for underwater near-horizontal target imaging with 40° pitch and 360° azimuth. This system is used for covert detection of sea and air targets by underwater platforms, compensating for the detection blind spots of traditional optoelectronic equipment on underwater vehicles, and significantly improving the detection performance of underwater vehicles. It has significant application value in areas such as underwater vehicle surface and airspace detection, and safety monitoring of underwater vehicle surfacing channels. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a transmedia Snell window edge panoramic imaging optical system provided in an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] Figure 1 This is a schematic diagram of a transmedia Snell window edge panoramic imaging optical system provided in an embodiment of the present invention. Following the light path, the left side is the object side, and the right side is the image side. From the object side, the system consists of: a pressure-resistant protective window (G1), an optical path folding mirror (G2), a wedge mirror (G3), a focusing lens group (G4), a front fixed imaging group (G5), and a rear fixed imaging group (G6).

[0023] In this embodiment of the invention, when performing underwater air imaging, the working wavelength is 450nm~700nm, the F# is 1.8, the imaging field of view is: elevation not less than 50°~90°, azimuth 360°, and it is compatible with a 2048×2048 visible light detector with a pixel size of 5.5μm.

[0024] In this embodiment of the invention, the staring imaging detection field of view is not less than 40°×40°; the scanning panoramic imaging is achieved by the motor driving the optical path folding mirror (G2), wedge mirror (G3), focusing mirror group (G4), front fixed imaging group (G5) and rear fixed imaging group (G6) and detector assembly to rotate around the vertical axis.

[0025] In this embodiment of the invention, the pressure-resistant protection window (G1) is a spherical meniscus concentric hemispherical lens (L11) used for aberration balance correction of the optical system.

[0026] In this embodiment of the invention, the optical path folding mirror (G2) is a prism or a reflector (L21) to fold the light beam at the edge of the Snell window. The light beam is folded by 48.6° so that the light beam passes through the center of the lens group G2 to G6 and is incident directly onto the center of the detector target surface.

[0027] In this embodiment of the invention, the wedge mirror (G3) is used to correct water dispersion, improve longitudinal compression of the optical system, and enhance the imaging quality of the optical system. The wedge mirror (G3) is also referred to as... Figure 1 The wedge-shaped mirror (L31) in the design is made of a high-refractive-index, high-dispersion material with a refractive index greater than 1.7 and a dispersion coefficient less than 32.

[0028] In this embodiment of the invention, a focusing lens group (G4) that can move back and forth along the optical axis is used to compensate for part of the defocusing effect caused by water disturbance, so as to achieve focusing functions for both near and far-distance imaging. Figure 1 The focusing lens (L41) is a meniscus lens with negative optical power.

[0029] When performing underwater air-to-air Snell window edge staring imaging using the system of this invention, the imaging beam is incident from the air medium, passes through the water medium and enters the pressure-resistant protective window (G1). After being converged by the spherical hemispherical protective window, the beam continues to propagate backward. Through the optical path deflector (G2), the imaging beam at the edge of the Snell window is deflected by 48.6° and incident at the center of the wedge mirror (G3). The spectral dispersion of the wedge mirror prism is used to compensate for the dispersion effect of the water body, and its longitudinal stretching effect is used to improve the longitudinal compression of the system. After passing through the wedge mirror (G3), the beam is successively refracted by the focusing lens group (G4), the front fixed imaging group (G5), and the rear fixed imaging group (G6), and finally imaged on the detector target surface.

[0030] The front fixed imaging group (G5) includes a first lens (L51), which is a meniscus lens with negative optical power; a second lens (L52), which is a cemented doublet lens with positive optical power; and a third lens (L53), which is a meniscus lens with positive optical power.

[0031] The rear fixed imaging group (G6) includes: a fourth lens (L61), which is a cemented doublet with positive optical power; a fifth lens (L62), which is a biconvex lens with positive optical power; and a sixth lens (L63), which is a cemented doublet with positive optical power.

[0032] When performing underwater panoramic imaging of the Snell window edge scanning using the system of this invention, the optical path folding mirror (G2), wedge mirror (G3), focusing mirror group (G4), front fixed imaging group (G5), rear fixed imaging group (G6), and detector group rotate 360° around the vertical axis of the optical system under the drive of a motor, thereby achieving panoramic time-sharing imaging.

[0033] Table 1 below provides specific design parameters for an optical system.

[0034] Table 1. Parameters for Underwater Snell Window Edge Panoramic Imaging

[0035]

[0036]

[0037] In Table 1, radius of curvature refers to the radius of curvature of each lens surface, thickness or spacing refers to the lens thickness or the distance between adjacent lens surfaces, material refers to the material used in the lens, and air refers to the medium between two lenses being air.

[0038] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0039] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A transmedia Snell window edge panoramic imaging optical system, characterized in that, It consists of a pressure-resistant protective window (G1), an optical path folding mirror (G2), a wedge mirror (G3), a focusing lens group (G4), a front fixed imaging group (G5), and a rear fixed imaging group (G6) arranged sequentially from the object side to the image side along the light direction, so as to realize underwater aerial Snell window edge staring imaging and panoramic scanning imaging. The pressure-resistant protection window (G1) is a spherical meniscus concentric hemispherical lens (L11) used for aberration balance correction of the optical system; The optical path folding mirror (G2) is a prism or a reflector that folds the beam at the edge of the Snell window by 48.6°, so that the beam passes through the center of the optical path folding mirror (G2), the wedge mirror (G3), the focusing mirror group (G4), the front fixed imaging group (G5), and the rear fixed imaging group (G6) and is incident directly onto the center of the detector target surface. The wedge mirror (G3) is used to correct water dispersion, improve longitudinal compression of the optical system, and enhance the imaging quality of the optical system. The wedge mirror (G3) has an Nd of 1.95 and a Vd of 17.

9. A focusing lens group (G4) that can move back and forth along the optical axis is used to compensate for some of the defocusing effect caused by water disturbance. The front fixed imaging group (G5) includes a first lens (L51), a second lens (L52), and a third lens (L53); the first lens (L51) is a meniscus lens with negative optical power, the second lens (L52) is a cemented doublet lens with positive optical power, and the third lens (L53) is a meniscus lens with positive optical power. The post-fixed imaging group (G6) includes: a fourth lens (L61), a fifth lens (L62), and a sixth lens (L63); the fourth lens (L61) is a cemented doublet with positive optical power, the fifth lens (L62) is a biconvex lens with positive optical power, and the sixth lens (L63) is a cemented doublet with positive optical power. Among them, the staring imaging detection field of view is not less than 40°×40°, and the scanning panoramic imaging is achieved by the motor driving the optical path folding mirror (G2), wedge mirror (G3), focusing mirror group (G4), front fixed imaging group (G5) and rear fixed imaging group (G6) and detector assembly to rotate around the vertical axis.

2. The system according to claim 1, characterized in that, When imaging underwater, the working wavelength is 450nm~700nm, the F# is 1.8, the imaging field of view is: elevation not less than 50°~90°, azimuth 360°, and it is compatible with 2048×2048 visible light detectors with a pixel size of 5.5μm.

3. The system according to claim 2, characterized in that, During underwater aerial Snell window edge scanning panoramic imaging, the optical path folding mirror (G2), wedge mirror (G3), focusing mirror group (G4), front fixed imaging group (G5), rear fixed imaging group (G6) and detector group rotate 360° around the vertical axis of the optical system under the drive of the motor, realizing panoramic time-sharing imaging.

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