Long-distance three-dimensional light field imaging long-wave infrared optical lens

Abstract

The invention discloses a long-distance three-dimensional light field imaging long-wave infrared optical lens, which comprises a main objective lens and a micro lens array which are coaxially arranged along a light path direction, and is used for simultaneously acquiring position, direction and color information of an object; the main objective lens comprises a first lens (1), a second lens (2), a third lens (3) and a fourth lens (4) which are coaxially arranged from front to back in the optical axis direction, and a micro-lens array (5) is arranged behind the fourth lens (4). Biplane parameterization (a micro-lens array and a detector focal plane) is adopted to capture and remotely detect a light field, and the device is composed of a main objective lens and the micro-lens array and can collect important information such as the position, direction and color of an object at the same time.

Description

Technical Field

[0001] The invention belongs to the technical field of optical system design and relates to a long-wave infrared optical lens for long-distance three-dimensional light field imaging. Background Art

[0002] A light field camera is a computational imaging optical system that uses dual-plane parameterization to capture and describe the light field. It has the advantage of being able to simultaneously obtain the position and direction information of the target with a single exposure. However, since the design optimization of the optical system performance and the research on machine vision algorithms in light field imaging are independent of each other, the light field resolution deteriorates with increasing distance, which makes the light field camera have the disadvantage of reduced three-dimensional imaging accuracy at long distances. At present, the research on three-dimensional light field imaging technology started early in foreign countries, and the technology is already quite mature. In 2016, the French Thales Group developed the world's first infrared light field camera, which can provide depth information between 1 and 10 meters, but has the problem of short imaging distance. China started late in this field, focusing more on depth extraction, super-resolution imaging, and multi-camera array imaging technology. Therefore, the exploration and research of long-distance infrared light field three-dimensional imaging systems can increase the possibility of their widespread application. Summary of the invention

[0003] (I) Purpose of the invention

[0004] The purpose of the present invention is to provide a long-distance three-dimensional light field imaging long-wave infrared optical lens, which can be applied to long-distance target simulation of a long-wave infrared optical system, and the optical system has excellent imaging performance.

[0005] (II) Technical solution

[0006] In order to solve the above technical problems, the present invention provides a long-distance three-dimensional light field imaging long-wave infrared optical lens, comprising a first lens 1, a second lens 2, a third lens 3, a fourth lens 4 and a microlens array 5 coaxially arranged from front to back along the light path. According to the direction of the light path, the left surface of all optical elements in the figure is defined as the front surface, and the right surface is defined as the back surface.

[0007] The first lens 1 is made of single crystal germanium, with a front surface radius ranging from 201 mm to 201.5 mm, a light aperture ranging from φ135.5 mm to φ136 mm, a rear surface radius ranging from 290 mm to 290.5 mm, a light aperture ranging from φ133.5 mm to φ134 mm, and an optical thickness ranging from 8.2 mm to 8.4 mm;

[0008] The second lens 2 is made of zinc selenide, with a front surface radius ranging from 512.5 mm to 512.8 mm, a clear aperture ranging from φ112.6 mm to φ112.8 mm, a rear surface radius ranging from 651.4 mm to 651.6 mm, a clear aperture ranging from φ112.4 to φ112.5 mm, and an optical thickness ranging from 3.2 mm to 3.4 mm;

[0009] The third lens 3 is made of single crystal germanium, the radius of the front surface is in the range of 111.6mm to 111.8mm, the clear aperture is in the range of φ62.5mm to φ62.6mm, the radius of the rear surface is in the range of 114.5mm to 114.7mm, the clear aperture is in the range of φ63.9mm to φ64mm, and the optical thickness is in the range of 4mm to 4.1mm;

[0010] The fourth lens 4 is made of single crystal germanium, the radius of the front surface is in the range of 74 mm to 74.1 mm, the clear aperture is in the range of φ59.3 mm to φ59.4 mm, the radius of the rear surface is in the range of 74 mm to 74.1 mm, the clear aperture is in the range of φ48.5 mm to φ48.6 mm, and the optical thickness is in the range of 16.4 mm to 16.5 mm;

[0011] The material of the microlens array 5 is chalcogenide glass IRG206, the aperture of a single microlens is 0.3 mm, the radius of the front surface varies in the range of 0.7 mm to 0.75 mm, the radius of the rear surface is flat, the aperture range is φ17 mm to φ18 mm, and the optical thickness range is 0.9 mm to 1 mm;

[0012] The distance between the first lens 1 and the second lens 2 varies in the range of 52.7 mm to 52.8 mm; the distance between the second lens 2 and the third lens 3 varies in the range of 119.6 mm to 119.7 mm; the distance between the third lens 3 and the fourth lens 4 varies in the range of 0.2 mm to 0.3 mm; the distance between the fourth lens 4 and the microlens array 5 varies in the range of 18.8 mm to 18.9 mm; the distance between the microlens array 5 and the detector image plane varies in the range of 0.36 mm to 0.37 mm.

[0013] (III) Beneficial effects

[0014] The long-wave infrared optical lens for long-distance three-dimensional light field imaging provided by the above technical solution uses dual-plane parameterization (microlens array, detector focal plane) to capture the light field and detect it at a long distance. It is composed of a main objective lens and a microlens array, and can simultaneously collect important information such as the position, direction and color of the object. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A system diagram of a long-wave infrared optical lens for long-distance three-dimensional light field imaging.

[0016] Figure 2 A schematic diagram of a microlens array 5 of a long-wave infrared optical lens for long-distance three-dimensional light field imaging.

[0017] Figure 3 It is the optical transfer function value of the main objective lens of a long-wave infrared optical lens for long-distance three-dimensional light field imaging.

[0018] Figure 4 This is a diagram of the optical transfer function values ​​of a long-wave infrared optical lens for long-distance three-dimensional light field imaging. DETAILED DESCRIPTION

[0019] 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 drawings and examples.

[0020] The technical performance indicators that can be achieved by the long-wave infrared optical lens for long-distance three-dimensional light field imaging in this embodiment are:

[0021] (1) Working band: 8μm~12.0μm;

[0022] (2) F#: 1.2;

[0023] (3) Focal length: 160 mm;

[0024] (4) Full field of view: 2ω = 11.8°;

[0025] (5) Single microlens aperture: 0.3mm.

[0026] The long-wave infrared optical lens for long-distance three-dimensional light field imaging in this embodiment uses dual-plane parameterization to capture the light field and detect it at a long distance, including a main objective lens and a microlens array, which can simultaneously collect the position, direction and color information of the object. The microlens array is used to replace the traditional detector window, which can realize long-distance detection in the long-wave infrared band and achieve zero crosstalk F# matching between the main objective lens and the microlens.

[0027] Reference Figure 1 and Figure 2 As shown, the main objective lens includes a first lens 1, a second lens 2, a third lens 3, and a fourth lens 4 coaxially arranged from front to back along the optical axis, and a microlens array 5 is arranged behind the fourth lens 4. According to the direction of the light path, the left surface of all optical elements in the figure is defined as the front surface, and the right surface is defined as the back surface.

[0028] The first lens 1 is made of single crystal germanium, with a front surface radius ranging from 201 mm to 201.5 mm, a light aperture ranging from φ135.5 mm to φ136 mm, a rear surface radius ranging from 290 mm to 290.5 mm, a light aperture ranging from φ133.5 mm to φ134 mm, and an optical thickness ranging from 8.2 mm to 8.4 mm;

[0029] The second lens 2 is made of zinc selenide, with a front surface radius ranging from 512.5 mm to 512.8 mm, a clear aperture ranging from φ112.6 mm to φ112.8 mm, a rear surface radius ranging from 651.4 mm to 651.6 mm, a clear aperture ranging from φ112.4 to φ112.5 mm, and an optical thickness ranging from 3.2 mm to 3.4 mm;

[0030] The third lens 3 is made of single crystal germanium, the radius of the front surface is in the range of 111.6mm to 111.8mm, the clear aperture is in the range of φ62.5mm to φ62.6mm, the radius of the rear surface is in the range of 114.5mm to 114.7mm, the clear aperture is in the range of φ63.9mm to φ64mm, and the optical thickness is in the range of 4mm to 4.1mm;

[0031] The fourth lens 4 is made of single crystal germanium, the radius of the front surface is in the range of 74 mm to 74.1 mm, the clear aperture is in the range of φ59.3 mm to φ59.4 mm, the radius of the rear surface is in the range of 74 mm to 74.1 mm, the clear aperture is in the range of φ48.5 mm to φ48.6 mm, and the optical thickness is in the range of 16.4 to 16.5 mm;

[0032] The material of the microlens array 5 is chalcogenide glass IRG206, the aperture of a single microlens is 0.3 mm, the number of arrays is 120×120, the radius of the front surface varies from 0.7 mm to 0.75 mm, the radius of the rear surface is flat, the aperture range is φ17 mm to φ18 mm, and the optical thickness range is 0.9 mm to 1 mm;

[0033] The distance between the first lens 1 and the second lens 2 varies in the range of 52.7 mm to 52.8 mm;

[0034] The distance between the second lens 2 and the third lens 3 varies in the range of 119.6 mm to 119.7 mm;

[0035] The distance between the third lens 3 and the fourth lens 4 varies in the range of 0.2 mm to 0.3 mm;

[0036] The distance between the fourth lens 4 and the microlens array 5 varies in the range of 18.8 mm to 18.9 mm;

[0037] The distance between the microlens array 5 and the detector image plane varies in the range of 0.36 mm to 0.37 mm.

[0038] Figure 3-4 This is a numerical diagram of the optical transfer function of the long-wave band of the infrared optical system simulated by optical software. The input wavelength is designed to be 8μm and 12μm, and the corresponding half fields of view are 0°, 2°, and 5°, respectively, the focal length is 160mm, and the F# is 1.2. Since the image quality of the positive field of view and the negative field of view is the same, only the positive field of view is used for input. The horizontal axis in the figure represents the spatial frequency, and the vertical axis represents the optical transfer function value.

[0039] Table 1 shows the long-wave imaging quality of the infrared optical system. It can be seen that the imaging quality of the infrared optical system from the central field of view to the edge field of view is excellent.

[0040] Table 1 Imaging quality of infrared optical system (MTF@33lp / mm)

[0041] Field of view theory 0 0.46 2 0.40 5 0.25

[0042] 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 long-distance three-dimensional light field imaging long-wave infrared optical lens, characterized in that: It includes a main objective lens and a microlens array coaxially arranged along the optical path, and simultaneously collects the position, direction and color information of the object.

2. The long-wave infrared optical lens for long-distance three-dimensional light field imaging as claimed in claim 1, characterized in that: The main objective lens comprises a first lens (1), a second lens (2), a third lens (3), and a fourth lens (4) which are coaxially arranged from front to back along the optical axis, and a microlens array (5) is arranged behind the fourth lens (4); according to the direction of the light path, the left side surfaces of all optical elements are defined as front surfaces, and the right side surfaces are defined as rear surfaces.

3. The long-wave infrared optical lens for long-distance three-dimensional light field imaging as claimed in claim 2, characterized in that: The first lens (1) is made of single crystal germanium, the radius of the front surface is in the range of 201 mm to 201.5 mm, the clear aperture is in the range of φ135.5 mm to φ136 mm, the radius of the rear surface is in the range of 290 mm to 290.5 mm, the clear aperture is in the range of φ133.5 mm to φ134 mm, and the optical thickness is in the range of 8.2 mm to 8.4 mm.

4. The long-wave infrared optical lens for long-distance three-dimensional light field imaging as claimed in claim 3, characterized in that: The second lens (2) is made of zinc selenide, the radius of the front surface is in the range of 512.5 mm to 512.8 mm, the light-clearing aperture is in the range of φ112.6 mm to φ112.8 mm, the radius of the rear surface is in the range of 651.4 mm to 651.6 mm, the light-clearing aperture is in the range of φ112.4 mm to φ112.5 mm, and the optical thickness is in the range of 3.2 mm to 3.4 mm.

5. The long-wave infrared optical lens for long-distance three-dimensional light field imaging as claimed in claim 4, characterized in that: The third lens (3) is made of single crystal germanium, the radius of the front surface is in the range of 111.6 mm to 111.8 mm, the clear aperture is in the range of φ62.5 mm to φ62.6 mm, the radius of the rear surface is in the range of 114.5 mm to 114.7 mm, the clear aperture is in the range of φ63.9 mm to φ64 mm, and the optical thickness is in the range of 4 mm to 4.1 mm.

6. The long-wave infrared optical lens for long-distance three-dimensional light field imaging as claimed in claim 5, characterized in that: The fourth lens (4) is made of single crystal germanium, the radius of the front surface is in the range of 74 mm to 74.1 mm, the aperture is in the range of φ59.3 mm to φ59.4 mm, the radius of the rear surface is in the range of 74 mm to 74.1 mm, the aperture is in the range of φ48.5 mm to φ48.6 mm, and the optical thickness is in the range of 16.4 mm to 16.5 mm.

7. The long-wave infrared optical lens for long-distance three-dimensional light field imaging as claimed in claim 6, characterized in that: The material of the microlens array (5) is chalcogenide glass IRG206, the aperture of a single microlens is 0.3 mm, the number of arrays is 120×120, the front surface radius ranges from 0.7 mm to 0.75 mm, the rear surface radius is flat, the light aperture ranges from φ17 mm to φ18 mm, and the optical thickness ranges from 0.9 mm to 1 mm.

8. The long-wave infrared optical lens for long-distance three-dimensional light field imaging as claimed in claim 7, characterized in that: The distance between the first lens (1) and the second lens (2) varies in the range of 52.7 mm to 52.8 mm; the distance between the second lens (2) and the third lens (3) varies in the range of 119.6 mm to 119.7 mm; and the distance between the third lens (3) and the fourth lens (4) varies in the range of 0.2 mm to 0.3 mm.

9. The long-wave infrared optical lens for long-distance three-dimensional light field imaging as claimed in claim 8, characterized in that: The distance between the fourth lens (4) and the microlens array (5) varies in the range of 18.8 mm to 18.9 mm.

10. The long-wave infrared optical lens for long-distance three-dimensional light field imaging as claimed in claim 9, characterized in that: The distance between the microlens array (5) and the detector image plane varies in the range of 0.36 mm to 0.37 mm.

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