CN216134467U

CN216134467U - Variable entropy compression sampling device of space camera

Info

Publication number: CN216134467U
Application number: CN202023153720.1U
Authority: CN
Inventors: 林长青; 孙胜利; 周双喜; 李璐芳; 喻琪超
Original assignee: Shanghai Institute of Technical Physics of CAS
Current assignee: Shanghai Institute of Technical Physics of CAS
Priority date: 2020-12-24
Filing date: 2020-12-24
Publication date: 2022-03-25
Anticipated expiration: 2030-12-24

Abstract

The utility model belongs to the technical field of detection of weak and small targets of space cameras, and discloses a variable-entropy compression sampling device of a space camera, wherein an AD1 quantization device is connected with a signal conditioning device and a signal processing device, and the output ends of the signal conditioning device and the signal processing device are connected with an AD2 quantization device; the AD1 quantization device is provided with a first AD converter and a first DA converter, and the output end of the first AD converter is connected with the input end of the first DA converter; the signal conditioning device is provided with a subtraction circuit unit and a signal amplification unit, and the output end of the subtraction circuit unit is connected with the input end of the signal amplification unit; the signal processing device is provided with a data memory and a time schedule controller; the AD2 quantization device is provided with a second AD converter and a second DA converter, and the output end of the second DA converter is connected with the input end of the second AD converter. The utility model can effectively reduce the data rate requirement of the space camera on the detection of the weak and small targets and reduce the requirement on AD resolution or transmission quantization bit number.

Description

Variable entropy compression sampling device of space camera

Technical Field

The utility model belongs to the technical field of detection of small and weak targets of space cameras, and particularly relates to a variable entropy compression sampling device of a space camera.

Background

At present, the imaging detection of weak and small targets by using a space camera is a hot spot in the current remote sensing field. The currently common detection scheme is that a space camera mounted on an aircraft (satellite, airplane, etc.) is adopted, various targets including airplanes, meteors and space stations are searched in the ground or in the air through high-resolution imaging, the mode of acquiring information is to image the targets through a photoelectric detector, and data after AD quantification is sent to a back end for processing or post-processing, so that the original data volume is generally huge, and the data rate is high.

With the development of remote sensing technology, pursuit of high time resolution, high space resolution and high radiation resolution is carried out, high-speed high-resolution AD (analog-to-digital) is used in a large amount on a technical route, generally 14 bits or more, so that the data volume of transmission and processing is further increased and the data rate is further improved, the front end original code rate of a typical imaging camera reaches the magnitude of hundreds of Gbps at present, a target signal needing to be extracted or detected is usually only the magnitude of a few Mbps, and most of acquired data is invalid data for detection. The front end of the traditional camera usually performs indiscriminate high-speed sampling and quantization and transmits the indiscriminate high-speed sampling and quantization to the back end for processing. However, the processing resources of the spacecraft are limited, which entails difficulties in transmission and processing.

Through the above analysis, the problems and defects of the prior art are as follows: for the target detection application environment, most data acquired by the traditional camera are invalid data, which causes resource waste of the spacecraft including power consumption, signal transmission links and the like, and the ground application system needs to process and process the original data again, so that the real-time performance is poor, target omission occurs easily, and the output benefit is low.

The difficulty in solving the above problems and defects is: the higher the A/D quantization bit number is, the higher the resolution is, the finer the detection identification granularity is, however, the larger the data quantity is, the more useless data is, the lower the resource utilization rate is, and a certain contradiction exists between the two.

The significance of solving the problems and the defects is as follows: aiming at the data rate requirement of the space camera on the detection of weak and small targets, the new method can reduce the requirement on high-resolution AD or transmission quantization digit, greatly reduce the requirements on acquisition, transmission and processing resources in the application occasion, obtain extremely high benefits while maintaining the performances of sensitivity, real-time detection and the like, reduce the complexity of an interface between the space camera and a data transmission system, improve the reliability and the service life of a spacecraft, reduce the processing complexity of a ground application system and improve the utilization rate of satellite and ground resources.

SUMMERY OF THE UTILITY MODEL

In order to solve the problems in the prior art, the utility model provides a variable entropy compression sampling device of a space camera.

The utility model is realized in such a way that a space camera variable entropy compression sampling device is provided with:

AD1 quantization means;

the AD1 quantization device is connected with a signal conditioning device and a signal processing device, and the output ends of the signal conditioning device and the signal processing device are connected with an AD2 quantization device.

Further, the AD1 quantization apparatus is provided with a first AD converter and a first DA converter, and the output end of the first AD converter is connected with the input end of the first DA converter.

Furthermore, the signal conditioning device is provided with a subtraction circuit unit and a signal amplification unit, and the output end of the subtraction circuit unit is connected with the input end of the signal amplification unit.

Further, the signal processing apparatus is provided with a data memory and a timing controller.

Further, the AD2 quantization apparatus is provided with a second AD converter and a second DA converter, and the output end of the second DA converter is connected with the input end of the second AD converter.

Further, the output end of the first AD converter is connected with the input end of the data memory; the output end of the first DA converter is connected with the input end of the subtraction circuit unit; the output end of the data memory is connected with the input end of the first DA converter; the output end of the time schedule controller is respectively connected with the input ends of the first AD converter, the first DA converter, the data memory, the second AD converter and the second DA converter; and the output end of the signal amplification unit is connected with the input end of the second AD converter.

By combining all the technical schemes, the utility model has the advantages and positive effects that: the analog signal output by the space camera detector is not subjected to high-resolution non-differential quantization, but is subjected to double AD quantization sampling, wherein an AD1 quantization module is used for reference sampling, a signal processing module feeds AD1 data back to the front end of the analog signal after DA1, subtraction is carried out, a residual signal is amplified by a signal conditioning module and then is sent to an AD2 quantization module for nonlinear quantization so as to improve a weak and small target signal, and quantization parameters are corrected through iterative training by comparing with a preset value, so that the large-amplitude compression of the imaging detection data rate is finally realized. The method has the characteristics of high sensitivity, strong real-time performance and small data operand, can effectively reduce the data rate requirement of a space camera on the detection of weak and small targets after being applied, and simultaneously reduces the requirement on high-resolution AD or transmission quantization digit.

This scheme can significantly reduce the amount of data relative to conventional sampling methods, as well as recent optical front-end compressive sampling schemes. Experiment results show that compared with the traditional sampling mode, the space detection camera adopting the method has the residence time of 10ms, the detector array of 1024 x 1024 elements and 2 spectral bands, the 16-bit quantization code rate of the traditional sampling mode is about 3.4Gbps, and the quantization code rate is reduced to 850Mbps after the method is adopted.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained from the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a variable entropy compression sampling apparatus of a space camera according to an embodiment of the present invention;

in the figure: 1. AD1 quantization means; 2. a signal conditioning device; 3. a signal processing device; 4. AD2 quantization means; 5. a first AD converter; 6. a first DA converter; 7. a subtraction circuit unit; 8. a signal amplification unit; 9. a data storage; 10. a time schedule controller; 11. a second AD converter; 12. a second DA converter.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.

In view of the problems in the prior art, the present invention provides a device for entropy-variable compressive sampling of a spatial camera, which is described in detail below with reference to the accompanying drawings.

As shown in fig. 1, the variable entropy compression sampling apparatus for a spatial camera according to an embodiment of the present invention includes: the AD1 quantization apparatus 1, the signal conditioning apparatus 2, the signal processing apparatus 3, the AD2 quantization apparatus 4, the first AD converter 5, the first DA converter 6, the subtraction circuit unit 7, the signal amplification unit 8, the data memory 9, the timing controller 10, the second AD converter 11, and the second DA converter 12.

The AD1 quantization device 1 of the present embodiment is connected with a signal conditioning device 2 and a signal processing device 3, and the output ends of the signal conditioning device 2 and the signal processing device 3 are connected with an AD2 quantization device 4.

In the embodiment, the AD1 quantization device 1 is provided with a first AD converter 5 and a first DA converter 6, wherein the output end of the first AD converter 5 is connected with the input end of the first DA converter 6; the first AD converter 5 is of type AD9204-20 and the first DA converter 6 is of type AD 9761.

In this embodiment, the signal conditioning device 2 is provided with a subtraction circuit unit 7 and a signal amplification unit 8, and an output end of the subtraction circuit unit 7 is connected with an input end of the signal amplification unit 8.

In the present embodiment, the signal processing apparatus 3 is provided with a data memory 9 and a timing controller 10.

In the present embodiment, the AD2 quantization apparatus 4 is provided with a second AD converter 11 and a second DA converter 12, and the output end of the second DA converter 12 is connected with the input end of the second AD converter 11; the second AD converter 11 is of type AD9204-20 and the second DA converter 12 is of type AD 9761.

In this embodiment, the output end of the first AD converter 5 is connected to the input end of the data memory 9; the output end of the first DA converter 6 is connected with the input end of the subtraction circuit unit 7; the output end of the data memory 9 is connected with the input end of the first DA converter 6; the output end of the time schedule controller 10 is respectively connected with the input ends of the first AD converter 5, the first DA converter 6, the data memory 9, the second AD converter 11 and the second DA converter 12; the output end of the signal amplifying unit is connected with the input end of the second AD converter 11.

The working principle of the utility model is as follows:

the push-broom camera images a target, 2 paths of analog signals output by the 1024-element infrared detector are firstly sent to an AD1 quantization module for AD conversion, two paths of intermediate resolution AD are selected, the residence time of the camera is set to be 1ms, the exposure time does not exceed the residence time and is set to be 500 us;

the data output by the AD1 quantization module is sent to a signal processing module, the current data is stored in a memory, the memory is arranged in an FPGA, the size of the memory is matched with the information amount generated by exposing a camera detector once, and each scanning line stores 1024 multiplied by 10 bits; then when the data of the next exposure is sent, the read data is sent to a first DA converter 6 of an AD2 quantization module;

a first DA converter 6 of the AD2 quantization module receives data and converts the data into an analog signal after being connected with an AD9761, the analog signal is fed back to the front end of a subtraction circuit unit 7 in the signal conditioning module for subtraction, and a subtracted residual signal is output, wherein the signal is removed from a slowly changing background;

filtering and nonlinear amplifying the residual signal in a signal conditioning device to adapt to the measuring range of an AD2 quantization module; the amplified signal is sent to an AD2 quantization module for analog-to-digital conversion, the AD2 can be a medium-low resolution DA, a voltage reference in an AD9761 quantization module and an AD2 quantization module is selected, dynamic adjustment can be carried out through a second DA to obtain the optimal target signal resolution, and the entropy of the signal is changed for output data; the data output by the AD2 quantization module completes nonlinear quantization, and the data volume is reduced.

The method comprises the steps of obtaining infrared images of an airport, reading in analog quantization analysis line by line, and reducing the single-spectrum-band data rate from 33Mbps of the traditional 16bit sampling to less than 5Mbps in scenes with more ground scenery and cloud layers and reducing the data rate from 33Mbps of the traditional 16bit sampling to less than 1Mbps in cloudy sunny weather for the images containing airplane targets after the method is adopted.

In the description of the present invention, "a plurality" means two or more unless otherwise specified; the terms "upper", "lower", "left", "right", "inner", "outer", "front", "rear", "head", "tail", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the utility model. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The above description is only for the purpose of illustrating the present invention and the appended claims are not to be construed as limiting the scope of the utility model, which is intended to cover all modifications, equivalents and improvements that are within the spirit and scope of the utility model as defined by the appended claims.

Claims

1. The utility model provides a space camera becomes entropy compression sampling device which characterized in that, space camera becomes entropy compression sampling device is provided with:

AD1 quantization means;

2. The spatial camera variable entropy compressive sampling device of claim 1, wherein the AD1 quantization device is provided with a first AD converter and a first DA converter, and the output end of the first AD converter is connected with the input end of the first DA converter; the signal conditioning device is provided with a subtraction circuit unit and a signal amplification unit, and the output end of the subtraction circuit unit is connected with the input end of the signal amplification unit; the signal processing device is provided with a data memory and a time sequence controller; the AD2 quantization device is provided with a second AD converter and a second DA converter, and the output end of the second DA converter is connected with the input end of the second AD converter.

3. The spatial camera variable entropy compressive sampling device of claim 2, wherein the first AD converter output is connected to the data memory input; the output end of the first DA converter is connected with the input end of the subtraction circuit unit; the output end of the data memory is connected with the input end of the first DA converter; the output end of the time schedule controller is respectively connected with the input ends of the first AD converter, the first DA converter, the data memory, the second AD converter and the second DA converter; and the output end of the signal amplification unit is connected with the input end of the second AD converter.