CN114488187A - A satellite formation imaging system and method based on multi-channel Fourier stack - Google Patents

Abstract

A formation imaging system and method based on multi-path Fourier lamination is characterized in that a formation imaging system is composed of a plurality of groups of optical cameras, a series of low-resolution overlapped images with different intensities are obtained by monochromatic light illumination, a high-resolution target image is quickly synthesized in an inversion mode, multiple images are sampled by overlapped surfaces for iteration to carry out phase solution, the Fourier lamination synthetic aperture is applied to on-orbit satellite formation flight high-resolution imaging, the application field of the Fourier lamination synthetic aperture on-orbit remote sensing imaging is expanded, the structural form is compact, and the integration complexity is low.

Description

A satellite formation imaging system and method based on multi-channel Fourier stack

technical field

The invention relates to a satellite formation imaging system and method based on a multi-channel Fourier stack, belonging to the design of an on-orbit formation flight system and the application field of remote sensing imaging.

Background technique

In order to meet the response requirements of on-orbit satellites with large field of view, high-resolution imaging and carrying capacity constraints, it is proposed to use multiple small-aperture optical systems to form sparse apertures with a certain filling ratio, and comprehensively process the observation results for object imaging. Make the final effect close to the observation effect of a large aperture optical system on the object.

The technologies such as expandable space block and optical synthetic aperture imaging can effectively solve the bottleneck of on-orbit high-resolution imaging technology for large-aperture remote sensors. The traditional large-caliber remote sensor has the engineering problems of high development cost and difficult installation and adjustment of the heaven and earth. Spatial division can be expanded. The spatial position of optical components assembled on rails is quantitatively complex, and the compensation and correction depends on the accuracy of mechanical control. The synthetic aperture interferometric imaging system requires that the sub-optical systems have the same orientation and co-phase, which puts forward higher error control requirements for design, processing, assembly and on-orbit assembly.

SUMMARY OF THE INVENTION

The technical problem solved by the present invention is: in view of the problems in the current prior art, the traditional large-caliber remote sensor has high development cost and difficult engineering for the consistency of the sky and the ground, and proposes a satellite formation imaging based on multi-channel Fourier stacking. system and method.

The present invention solves the above-mentioned technical problems through the following technical solutions:

A satellite formation imaging system based on multi-channel Fourier stacking, including optical cameras for recording all images in different positions and overlapping areas, the number of optical camera groups is determined according to the satellite formation imaging task, the external light source illuminates the target, and the optical The formation imaging system composed of cameras receives the illumination field reflected by the target and generates a low-resolution image. The formation imaging system iteratively reconstructs a high-resolution image in the Fourier domain through an external imaging processing system.

The formation imaging system receives the illumination field reflected by the target, and can receive at different angles and through different spectrums.

The external light source is natural light or polarized light.

The optical camera includes an optical lens and a detector. The optical lens is used to collect the reflected light of the target, and the detection is used to receive the reflected light of the target after focusing processing by the optical lens, and obtain a low-resolution image associated with the sequence of external light sources.

The optical camera further includes an optical filter and a polarization module, all of which are arranged on the optical path between the optical lens and the detector, and perform filtering and polarization processing on the focused reflected light output by the optical lens.

The formation imaging system sequentially acquires the reflected image data of each target sample at different incident angles, and performs operations to generate a reconstructed image of each sample, iteratively updates the overlapping area in the Fourier domain, and restores the phase data to generate a high-resolution image of the target. .

A detector is arranged at the focal plane of the formation imaging system for collecting the imaging light emitted by the formation imaging system.

A satellite formation imaging method based on multi-channel Fourier stack, the steps are as follows:

(1) Launch the formation imaging system, dynamically track and receive the initial orbit detection light field data;

(2) Set the first position to the fifth position of the formation imaging system. After the initial orbit detection light field data is accumulated for one cycle, the formation imaging system is used to improve the trajectory and collect the light field distribution in each detection direction at the second position;

(3) After accumulating the optical field data of the orbit detection at the second position for a period, the trajectory is improved by the formation imaging system, and the distribution of the optical field in each detection direction at the third position is collected;

(4) After accumulating the light field data of the orbit detection at the third position for a period, the formation imaging system is used to improve the trajectory, and the light field distribution in each detection direction at the fourth position is collected. The overlapping information of the light field distribution builds a Fourier domain model;

(5) After accumulating the light field data of the orbit detection at the fourth position for a period, the trajectory is improved by the formation imaging system, and the light field distribution in each detection direction at the fifth position is collected, and the rules are set according to the sparse distribution and covered by partial overlap. The target imaging area is obtained, and a high-resolution image of the target imaging area is obtained through an iterative phase recovery algorithm.

The first position is the position of the optical system, and the image information of multiple sets of overlapping positions is generated by controlling the transformation to calculate the phase information to obtain a high-resolution image.

The advantages of the present invention compared with the prior art are:

(1) A satellite formation imaging system and method based on multi-channel Fourier stacking provided by the present invention adopts monochromatic light illumination to obtain a series of low-resolution overlapping images of different intensities, and quickly inverts and synthesizes high-resolution target images. The formation flying multi-optical system receives focused light from different illumination radiations (angles, wavelengths, etc.), obtains a series of low-resolution intensity images with different illumination intensity information, and uses overlapping surface sampling multi-image iteratively to perform phase solution to realize the Fourier stack. Layer synthetic aperture is applied to high-resolution imaging of in-orbit satellite formation flight, with compact structure and low integration complexity;

(2) The present invention adopts a new method of satellite formation imaging based on multi-channel Fourier stacking, and recovers the lost optical field phase by taking Fourier space intensity images of different regions and measuring overlapping redundant information, thereby increasing the optical aperture and viewing angle of the imaging system. Compared with the traditional synthetic aperture implementation, the common-phase detection adjustment mechanism is not used, and the imaging capability similar to the overall aperture is realized, and the sampling image quality of the on-orbit remote sensor is improved. Expanded the application field of Fourier stack sparse synthetic aperture imaging technology.

Description of drawings

1 is a schematic diagram of a satellite formation imaging system based on a multi-channel Fourier stacking method provided by the invention;

2 is a simplified schematic diagram of the arrangement of the sparse aperture structure of the satellite formation imaging system provided by the invention;

3 is a schematic diagram of a typical method of flight push-broom of a satellite formation imaging system provided by the invention;

4 is a schematic diagram of a synthetic aperture image reconstruction effect provided by the invention;

5 is a simplified schematic diagram of the Fourier stack synthetic aperture imaging experimental device provided by the invention;

Detailed ways

A satellite formation imaging system and method based on multi-channel Fourier stacking, by acquiring a series of low-resolution intensity images under different illumination radiation angles and wavelengths, and using overlapping sampling information phase recovery iterative algorithm to obtain high-resolution target images, System components include:

Multiple groups of optical cameras are used to record all images at different positions and with overlapping areas. The number of optical camera groups is determined according to the satellite formation imaging task. The external light source illuminates the target. The formation imaging system composed of optical cameras receives the illumination field reflected by the target and generates a Generate low-resolution images, and the formation imaging system iteratively reconstructs high-resolution images in the Fourier domain through an external imaging processing system;

Among them, the formation imaging system receives the illumination field reflected by the target, and can receive it at different angles and through different spectrums;

The external light source is natural light or polarized light; the optical camera includes an optical lens and a detector. The optical lens is used to collect the reflected light of the target, and the detection is used to receive the reflected light of the target after being focused by the optical lens, and obtain the low-level light associated with the external light source sequence. distinguish images;

The optical camera further includes an optical filter and a polarization module, which are all arranged on the optical path between the optical lens and the detector, and perform filtering and depolarization processing on the focused reflected light output by the optical lens;

The formation imaging system sequentially acquires the reflected image data of each target sample at different incident angles, and performs operations to generate a reconstructed image of each sample, iteratively updates the overlapping area in the Fourier domain, and restores the phase data to generate a high-resolution image of the target;

A detector is arranged at the focal plane of the formation imaging system to collect the imaging light emitted by the formation imaging system;

Through the above formation imaging system, a formation imaging method is proposed. The specific steps are as follows:

(1) Launch the formation imaging system, dynamically track and receive the initial orbit detection light field data;

(2) Set the first position to the fifth position of the formation imaging system. After the initial orbit detection light field data is accumulated for one cycle, the formation imaging system is used to improve the trajectory and collect the light field distribution in each detection direction at the second position;

Wherein, the first position is the position of the optical system, and the image information of multiple sets of overlapping regions of positions is generated by controlling the transformation to solve the phase information to obtain a high-resolution image;

(3) After accumulating the optical field data of the orbit detection at the second position for a period, the trajectory is improved by the formation imaging system, and the distribution of the optical field in each detection direction at the third position is collected;

(4) After accumulating the light field data of the orbit detection at the third position for a period, the formation imaging system is used to improve the trajectory, and the light field distribution in each detection direction at the fourth position is collected. The overlapping information of the light field distribution builds a Fourier domain model;

(5) After accumulating the light field data of the orbit detection at the fourth position for a period, the trajectory is improved by the formation imaging system, and the light field distribution in each detection direction at the fifth position is collected, and the rules are set according to the sparse distribution and covered by partial overlap. The target imaging area is obtained, and a high-resolution image of the target imaging area is obtained through an iterative phase recovery algorithm.

Further description is given below according to specific embodiments:

As shown in FIG. 1 to FIG. 5 , in the satellite formation imaging system based on multi-channel Fourier stack, the light source 3 illuminates the target 4, and the formation imaging system 1 receives the illumination field reflected by the target to form a series of low-resolution images, and uses the processing system 5 Iteratively reconstructs high-resolution images in the Fourier domain; the formation imaging system 1 is composed of multiple groups of optical cameras 2, and the optical cameras 2 record multiple images at different positions and overlapping areas;

The way that the formation imaging system 1 receives the reflected illumination field of the target can be received through different angles or through different spectrums;

The light source 3 can be natural light or polarized light;

The optical camera 2 is composed of an optical lens and a detector, wherein the optical lens collects the light reflected by the illuminated target, and the detector receives the light focused by the optical lens, and acquires the low-resolution images associated with the sequence of the light sources 3 image;

The optical camera 2 may also include an optical filter and a polarization module, which are located in the optical path between the optical lens and the detector;

The formation imaging system 1 sequentially acquires the reflected image data of each target sample at different incident angles, performs an operation to generate a reconstructed image of each sample, iteratively updates the overlapping area in the Fourier domain, and restores the phase data to generate a high-resolution image of the target;

The specific steps of the formation imaging method are as follows:

Step 1, launch a group of satellite formation imaging systems, dynamically track and receive initial orbit detection light field data 6;

Step 2: After a period of data accumulation, the satellite formation imaging system performs the first series of trajectory improvement, and collects the light field distributions in each detection direction at the second position 7;

Step 3: After a period of data accumulation, the satellite formation imaging system executes the second series of trajectory improvement, and collects the light field distribution in each detection direction at the third position 8 ;

Step 4. After a period of data accumulation, the satellite formation imaging system performs the third series of trajectory improvement, collects the light field distribution 9 in each detection direction at the fourth position, and compares the overlapping information of the images to construct a Fourier domain model;

Step 5. After a period of data accumulation, the satellite formation imaging system performs the fourth series of trajectory improvement, collects the light field distribution 10 in each detection direction at the fifth position, and covers the target in a partially overlapping manner according to the rules set by the sparse distribution. In the imaging area 11, a high-resolution image of the target imaging area is obtained through an iterative phase recovery algorithm.

Specifically, steps 2 to 4 are not limited to this light field arrangement order to jointly construct an imaging area covering the entire target;

The monochromatic light 12 illuminates the target 13 located at the focal plane of the focusing mirror 14. Additional optical elements such as filters and polarizers are omitted in the figure. The imaging light is collected by the detector 16 located at the focal plane of the optical system 15. By using The translation stage moves the optical system 15 multiple times to sample the complete area of Fourier space, capturing multiple low-resolution images 17 to resolve and synthesize high-resolution target images.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can use the methods and technical contents disclosed above to improve the present invention without departing from the spirit and scope of the present invention. The technical solutions are subject to possible changes and modifications. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solutions of the present invention belong to the technical solutions of the present invention. protected range.

The content not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims (9)

1. A multi-path fourier stack based satellite formation imaging system, comprising:

the system comprises optical cameras, wherein the optical cameras are used for recording all images of different positions and overlapped areas, the number of groups of the optical cameras is determined according to a satellite formation imaging task, an external light source illuminates a target, a formation imaging system formed by the optical cameras receives an illumination field reflected by the target and generates a low-resolution image, and the formation imaging system iteratively reconstructs a high-resolution image of a Fourier domain through an external imaging processing system.

2. The multi-path fourier stack based satellite formation imaging system of claim 1, wherein:

the formation imaging system receives the illumination field reflected by the target, can receive the illumination field at different angles and can receive the illumination field through different light spectrums.

3. The multi-path fourier stack based satellite formation imaging system of claim 2, wherein:

the external light source is natural light or polarized light.

4. A multi-path fourier stack based satellite formation imaging system according to claim 3, wherein:

the optical camera comprises an optical lens and a detector, wherein the optical lens is used for collecting target reflected light, detecting the target reflected light after the target reflected light is focused by the optical lens, and acquiring a low-resolution image associated with an external light source sequence.

5. The multi-path fourier stack based satellite formation imaging system of claim 4, wherein:

the optical camera further comprises a filter and a polarization module which are arranged on a light path between the optical lens and the detector and used for filtering and polarizing the focused target reflected light output by the optical lens.

6. The multi-path fourier stack based satellite formation imaging system of claim 5, wherein:

the formation imaging system sequentially obtains reflection image data of each target sample at different incidence angles, executes operation to generate a reconstructed image of each sample, iteratively updates an overlapping area in a Fourier domain, and restores phase data to generate a high-resolution image of the target.

7. The multi-path fourier stack based satellite formation imaging system of claim 6, wherein:

and a detector is arranged on the focal plane of the formation imaging system and is used for collecting imaging light rays emitted by the formation imaging system.

8. A method for forming an image of a satellite based on a multi-path fourier stack as claimed in claim 7, characterized by the steps of:

(1) the transmitting formation imaging system dynamically tracks and receives the initial track detection light field data;

(2) setting a first position to a fifth position of the formation imaging system, after the initial orbit detection light field data is accumulated for one cycle, carrying out track improvement through the formation imaging system, and collecting light field distribution in each detection direction at the second position;

(3) after the second position track detection light field data are accumulated for one period, track improvement is carried out through a formation imaging system, and light field distribution in each detection direction at a third position is collected;

(4) after the third position track detection light field data are accumulated for one period, track improvement is carried out through a formation imaging system, light field distribution in each detection direction at the fourth position is collected, and a Fourier domain model is constructed through light field distribution overlapping information obtained in the step (2) and the step (3);

(5) after the fourth position track detection light field data are accumulated for one period, track improvement is carried out through a formation imaging system, light field distribution in each detection direction at the fifth position is collected, a target imaging area is covered according to sparse distribution setting rules and a partial overlapping mode, and a high-resolution image of the target imaging area is obtained through an iterative phase recovery algorithm.

9. A method for forming an image of a satellite based on a multi-path fourier stack as claimed in claim 8, wherein:

the first position is the position of the optical system, and the image information of a plurality of groups of position overlapping areas is generated through control conversion to calculate the phase information, so that a high-resolution image is obtained.

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