A single-lens long-wave infrared imager and an image processing method thereof

Abstract

The application provides a single-lens long-wave infrared imager and an image processing method thereof, comprising a single-lens imaging optical lens, the single-lens imaging optical lens is a double aspheric lens; the long-wave infrared detector is a surface array detector, the pixel scale is 640*512, the single-lens imaging optical lens is connected with the long-wave infrared detector; a processing circuit board is arranged on the long-wave infrared detector, and the processing circuit board has an information processing unit; the information processing unit is configured to restore a low-resolution original image captured by the single-lens long-wave infrared imager into a high-resolution image; based on the design idea of "optics-image" integration, the single double aspheric lens is used as the optical lens, so that the volume of the whole infrared imaging system is reduced by more than 30%, the weight is reduced by more than 40%, the cost is reduced by more than 40%, and the total optical system efficiency in the 8-12 mu m wave band is also improved.

Description

Technical Field

[0001] This application relates to the field of computational imaging technology, and in particular to a single-lens long-wave infrared imager and its image processing method. Background Technology

[0002] With the rapid development of optoelectronic equipment in military reconnaissance, unmanned vehicles, security monitoring, and disaster relief, the demand for high-quality images is increasing. Currently, optical systems mainly improve image quality by increasing the number of lenses or using special surface shapes;

[0003] However, while improving the imaging quality of the system, it increases the overall size, weight and cost of the system, which contradicts the design requirements of miniaturization, lightweighting and low cost.

[0004] To address the challenges of miniaturization, weight reduction, and low cost in imaging systems, this application proposes a single-lens long-wave infrared imager and its image processing method. Summary of the Invention

[0005] The purpose of this application is to address the above problems by providing a single-lens long-wave infrared imager and its image processing method.

[0006] First aspect:

[0007] This application provides a single-lens long-wave infrared imager, comprising:

[0008] A single-lens imaging optical lens, wherein the single-lens imaging optical lens is a double aspherical lens;

[0009] The long-wave infrared detector is an area array detector with a pixel size of 640×512. The single-lens imaging optical lens is connected to the long-wave infrared detector. The long-wave infrared detector is equipped with a pre-processing circuit board, which has an information processing unit.

[0010] The information processing unit is configured to restore the low-resolution image captured by the single-lens long-wave infrared imager to a high-resolution image.

[0011] According to the technical solution provided in the embodiments of this application, the number of double aspherical lenses is one.

[0012] According to the technical solution provided in the embodiments of this application, the double aspherical lens includes a front surface and a rear surface, wherein the front surface is a first aspherical surface, and the coefficient of the first aspherical surface is A = -5.101660 × 10⁻⁶. -7 B = 1.837840 × 10 -11 C = -3.707620 × 10 -13 D = -4.637340 × 10-17 Its radius ranges from 109mm to 110mm, and its light-transmitting aperture ranges from φ70.5mm to φ71.5mm; the rear surface is a second aspherical surface, and the coefficient of the second aspherical surface is A = -5.155260 × 10⁻⁶. -7 B = 1.321300 × 10 -10 C = -7.104970 × 10 -13 D = 1.814090 × 10 -16 The radius ranges from 212.5mm to 213.5mm, and the aperture ranges from φ70.5mm to φ71.5mm.

[0013] According to the technical solution provided in the embodiments of this application, the center thickness of the double aspherical lens ranges from 9.5mm to 10.5mm.

[0014] According to the technical solution provided in the embodiments of this application, the optical material of the double aspherical lens is germanium.

[0015] The second aspect:

[0016] This application also provides a single-lens long-wave infrared imager and its image processing method, the method comprising the following steps:

[0017] The scene is photographed using the single-lens long-wave infrared imager with the double aspherical lenses to obtain the original image, which is a low-resolution image.

[0018] The original image and the PSF of the double aspherical lens are input into the information processing unit, which has the ADMM algorithm built in.

[0019] The original image is restored using the ADMM algorithm and the PSF.

[0020] Compared with the prior art, the beneficial effects of this application are as follows: The optical lens used in this application is a double aspherical lens, which is connected to a long-wave infrared detector. A processing circuit board is provided on the long-wave infrared detector, and an information processing unit is also provided on the processing circuit board. The information processing unit is mainly used to restore the original image captured by the single-lens long-wave infrared imager, thereby improving its resolution. In use, a single-lens long-wave infrared imager based on a double aspherical lens is used to capture images of a scene, and the captured images are input into the information processing unit for processing. The processed image is a high-resolution image. This application is based on "optical— The integrated design concept of "image processing" replaces the existing technology of using multiple lenses and various optical materials to design optical lenses by adopting a single double aspherical lens as the optical lens and combining it with image processing algorithms. This reduces the size of the entire infrared imaging system by more than 30%, the weight by more than 40%, and the cost by more than 40%. The long-wave infrared imager is used to capture images of the scene, and the captured images are input into the information processing unit for processing and restoration. The spatial resolution of the restored image can reach the cutoff frequency of the infrared detector, and the overall efficiency of the optical system in the 8μm to 12μm band can reach more than 93%. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the principle of a single-lens long-wave infrared imager provided in an embodiment of this application;

[0022] Figure 2 This is a graph showing the optical transfer function of a single-lens long-wave infrared imager.

[0023] Figure 3 This is a flowchart of the image processing of a single-lens long-wave infrared imager.

[0024] The text labels in the image represent:

[0025] 1. Single-lens imaging optical lens; 3. Information processing unit. Detailed Implementation

[0026] To enable those skilled in the art to better understand the technical solution of this application, the application will be described in detail below with reference to the accompanying drawings. The description in this section is only exemplary and explanatory, and should not be used to limit the scope of protection of this application.

[0027] Example 1

[0028] This application provides a single-lens long-wave infrared imager with a working wavelength of 8μm to 12μm, a diagonal field of view of 12°, a focal length of f = 70mm, and an F-number of 1.0.

[0029] Please refer to Figures 1-3 This embodiment provides a single-lens long-wave infrared imager, comprising:

[0030] A single-lens imaging optical lens 1, wherein the single-lens imaging optical lens 1 is a double aspherical lens;

[0031] The long-wave infrared detector is an area array detector with a pixel size of 640×512. The single-lens imaging optical lens 1 is connected to the long-wave infrared detector. The long-wave infrared detector is equipped with a processing circuit board, which has an information processing unit 3.

[0032] The information processing unit 3 is configured to restore the low-resolution raw image captured by the single-lens long-wave infrared imager to a high-resolution image.

[0033] Specifically, in this embodiment, the single-lens imaging optical lens 1 uses a double aspherical lens; the long-wave infrared detector is an area array detector with a pixel size of 640×512; the lens barrel of the single-lens imaging optical lens 1 is provided with a connection interface, which is connected to the single-lens long-wave infrared detector and fixed together with screws; the long-wave infrared detector is also provided with a processing circuit board, which has an information processing unit 3. The information processing unit 3 is configured to restore the low-resolution image obtained by the single-lens long-wave infrared imager from the external scene to a high-resolution image.

[0034] Furthermore, the number of the double aspherical lenses is one.

[0035] Specifically, in this embodiment, the number of double aspherical lenses is one. Using one double aspherical lens not only ensures the quality of the captured image, but also reduces the weight, size and cost of the system.

[0036] Furthermore, the double aspherical lens includes a front surface and a rear surface, wherein the front surface is a first aspherical surface, and the coefficient of the first aspherical surface is A = -5.101660 × 10⁻⁶. -7 B = 1.837840 × 10 -11 C = -3.707620 × 10 -13 D = -4.637340 × 10 -17 Its radius ranges from 109mm to 110mm, and its light-transmitting aperture ranges from φ70.5mm to φ71.5mm; the rear surface is a second aspherical surface, and the coefficient of the second aspherical surface is A = -5.155260 × 10⁻⁶. -7 B = 1.321300 × 10 -10C = -7.104970 × 10 -13 D = 1.814090 × 10 -16 The radius ranges from 212.5mm to 213.5mm, and the aperture ranges from φ70.5mm to φ71.5mm.

[0037] Specifically, in this embodiment, based on the optical path direction, the left surface of all optical elements in the diagram is designated as the front surface, and the right surface as the rear surface. Both the front and rear surfaces are aspherical, but their parameters are different. The front surface is a first aspherical surface, and the coefficient of the first aspherical surface is A = -5.101660 × 10⁻⁶. -7 B = 1.837840 × 10 -11 C = -3.707620 × 10 -13 D = -4.637340 × 10 -17 Its radius ranges from 109mm to 110mm, and its light-transmitting aperture ranges from φ70.5mm to φ71.5mm; the coefficient of the second aspherical surface is A = -5.155260 × 10⁻⁶. -7 B = 1.321300 × 10 -10 C = -7.104970 × 10 -13 D = 1.814090 × 10 -16 The radius ranges from 212.5mm to 213.5mm, and the aperture ranges from φ70.5mm to φ71.5mm.

[0038] Furthermore, the center thickness of the double aspherical lens ranges from 9.5 mm to 10.5 mm.

[0039] Specifically, in this embodiment, the range is the constraint range of the optical lens center thickness design.

[0040] Furthermore, the optical material of the double aspherical lens is germanium.

[0041] Specifically, in this embodiment, germanium is chosen as the material for the double aspherical lens because germanium has the characteristics of high refractive index and good transmittance in the long-wave infrared band, and is a commonly used infrared material. In this embodiment, the design of the single lens optical lens 1 is achieved by matching the refractive index of the material with the center thickness and surface shape of the double aspherical lens.

[0042] Example 2

[0043] This application provides a single-lens long-wave infrared imager and a method for processing its images, the method comprising the following steps:

[0044] 1. Using the single-lens long-wave infrared imager with the double aspherical lenses, the scene is photographed to obtain an original image, wherein the original image is a low-resolution image;

[0045] Specifically, a single-lens long-wave infrared imager equipped with the aforementioned double aspherical lenses is used to photograph the external scene to obtain an original image. The original image is a low-resolution image, which means a blurry image that is not clearly visible.

[0046] 2. Input the original image and the PSF of the double aspherical lens into the information processing unit, wherein the information processing unit has a built-in ADMM algorithm;

[0047] Specifically, the original image obtained by the capture and the PSF of the double aspherical lens are input into the information processing unit for processing; the information processing unit has a built-in ADMM algorithm, which is existing technology, and the PSF is the point spread function, which is well known to those in the field and will not be described in detail here.

[0048] 3. Restore the original image using the ADMM algorithm and the PSF;

[0049] The ADMM algorithm is the alternating direction multiplier method, which is a prior art. The original image is restored using the ADMM algorithm and the PSF of the double aspherical lens, and the restored image is formed as the first image.

[0050] 4. Capture a high-resolution reference image of the same scene using a standard long-wave infrared imager with the same optical parameters and designed using existing technology;

[0051] The same scene is photographed using an existing standard long-wave infrared imager, and the operating band, diagonal field of view and F-number of the existing standard long-wave infrared imager are consistent with the operating conditions in this application. After the photograph is taken, a second image is formed. The second image has a high resolution, which means a clear image. The first image is used as a reference image. The scene is consistent with the scene photographed by the imager equipped with double aspherical lenses.

[0052] 5. Input the first image and the second image into the discrimination program set in the information processing unit, and perform similarity discrimination calculation based on the SSIM (structural similarity) evaluation method. If the similarity is greater than 95%, output the second image as the output image of the single-lens long-wave infrared imager.

[0053] If the similarity is less than 95%, random perturbation should be added to the ADMM algorithm and PSF for correction. This correction method is a type of correction method in the prior art, which will not be described in detail here. Then, steps 3 and 4 are repeated until a restored image that meets the requirements, i.e., a high-resolution image, is output.

[0054] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. The above descriptions are only preferred embodiments of this application. It should be noted that due to the limitations of written expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this invention, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of this application.

Claims

1. An image processing method for a single-lens long-wave infrared imager, characterized in that, Single-lens long-wave infrared imagers include: A single-lens imaging optical lens (1), wherein the single-lens imaging optical lens (1) is a double aspherical lens; the number of double aspherical lenses is one; The long-wave infrared detector is an array detector with a pixel size of 640×512. The single-lens imaging optical lens (1) is connected to the long-wave infrared detector. The long-wave infrared detector is provided with a pre-processing circuit board, and the pre-processing circuit board has an information processing unit (3). The information processing unit (3) is configured to restore the low-resolution image captured by the single-lens long-wave infrared imager to a high-resolution image; Image processing methods include the following steps: The scene is photographed using the single-lens long-wave infrared imager with the double aspherical lenses to obtain the original image, which is a low-resolution image. The original image and the PSF of the double aspherical lens are input into the information processing unit, which has the ADMM algorithm built in. The original image is restored using the ADMM algorithm and the PSF.

2. The image processing method for a single-lens long-wave infrared imager according to claim 1, characterized in that, The double aspherical lens includes a front surface and a rear surface. The front surface is a first aspherical surface with coefficients A = -5.101660 × 10⁻⁷, B = 1.837840 × 10⁻¹¹, C = -3.707620 × 10⁻¹³, ​​and D = -4.637340 × 10⁻¹⁷. Its radius ranges from 109 mm to 110 mm, and its aperture ranges from φ70.5 mm. φ71.5mm; the rear surface is a second aspherical surface with coefficients A=-5.155260×10-7, B=1.321300×10-10, C=-7.104970×10-13, D=1.814090×10-16, a radius range of 212.5mm~213.5mm, and a light transmission aperture range of φ70.5mm~φ71.5mm.

3. The image processing method for a single-lens long-wave infrared imager according to claim 2, characterized in that, The center thickness of the double aspherical lens ranges from 9.5 mm to 10.5 mm.

4. The image processing method for a single-lens long-wave infrared imager according to claim 3, characterized in that, The optical material of the double aspherical lens is germanium.

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