A variable entropy compression sampling system, control method, medium and terminal for a space camera
By adopting variable entropy compression sampling system and dual AD quantization sampling technology in spatial cameras, the problem of spatial cameras obtaining invalid data in weak target detection is solved, and a significant reduction in data volume and improved detection sensitivity is achieved.
Patent Information
- Application Number
- CN202011551731.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-12-24
- Publication Date
- 2025-06-13
- Estimated Expiration
- 2040-12-24
AI Technical Summary
Most of the data obtained by existing spatial cameras in the detection of weak targets is invalid data, resulting in waste of resources and poor real-time performance, making it difficult to effectively detect weak targets.
Using variable entropy compression sampling system, through dual AD quantization sampling technology, reference sampling is performed first, then signal conditioning and feedback subtraction, and finally nonlinear quantization is performed to reduce the data volume.
It significantly reduces the amount of data, improves the effectiveness of data and detection sensitivity, reduces resource requirements and processing complexity, and improves the reliability and life of the spacecraft.
Smart Images
Figure CN112615625B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of weak target detection for space cameras, and particularly relates to a variable entropy compressive sampling system, a control method, a medium and a terminal for a space camera. Background Technique
[0002] At present, using a space camera for weak target imaging detection is a hot topic in the current remote sensing field. The commonly used detection scheme at present is to use a space camera installed on an aircraft (such as a satellite, an airplane, etc.), and to achieve ground or air search for various targets including airplanes, meteors, and space stations through high-resolution imaging. The way to obtain information is usually to image the target through an optoelectronic detector, and send the data after AD quantization to the backend for processing or post-processing. The amount of original data is generally quite large, and the data rate is relatively high.
[0003] With the development of remote sensing technology, in the pursuit of high temporal resolution, high spatial resolution, and high radiation resolution, a large number of high-speed high-resolution ADs are involved in the technical route, generally 14 bits or more. This will inevitably lead to a further increase in the amount of data to be transmitted and processed, and a further increase in the data rate. Currently, the typical imaging camera has reached the order of hundreds of Gbps in the front-end original code rate, while the target signal to be extracted or detected is often only of the order of a few Mbps. For detection, most of the acquired data is invalid data. The front-end of traditional cameras often performs non-discriminatory high-speed sampling and quantization and transmits it to the backend for processing. However, the processing resources of space vehicles are limited, which inevitably brings difficulties in transmission and processing.
[0004] Through the above analysis, the problems and defects existing in the prior art are as follows: for the target detection application environment, most of the data acquired by traditional cameras is invalid data, resulting in waste of resources of spacecraft including power consumption, signal transmission links, etc. The ground application system needs to process and process the original data again, with poor real-time performance and easy target omission, and low output efficiency.
[0005] The difficulty in solving the above problems and defects is: the higher the A / D quantization bit number, the higher the resolution, and the finer the recognition granularity of detection. However, the larger the amount of data, the more useless data, and the lower the resource utilization rate. There is a certain contradiction between the two.
[0006] The significance of solving the above problems and defects is as follows: In response to the data rate requirements of space cameras for detecting weak targets, the new method can reduce the demand for high-resolution AD or transmission quantization bits, greatly reducing the acquisition, transmission, and processing resource requirements in this application scenario. While maintaining performance such as sensitivity and real-time detection, it achieves extremely high efficiency, reduces the interface complexity between the space camera and the data transmission system, improves the reliability and lifespan of the spacecraft, and also reduces the processing complexity of the ground application system, improving the utilization rate of space-ground resources. Summary of the Invention
[0007] To solve the problems existing in the prior art, the present invention provides a variable entropy compression sampling system, control method, medium, and terminal for a space camera.
[0008] The present invention is implemented as follows. A variable entropy compression sampling system for a space camera is provided with:
[0009] AD1 quantization device;
[0010] The AD1 quantization device is connected to 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 to an AD2 quantization device.
[0011] Further, 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 to the input end of the first DA converter.
[0012] Further, 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 to the input end of the signal amplification unit.
[0013] Further, the signal processing device is provided with a data memory and a timing controller.
[0014] Further, 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 to the input end of the second AD converter.
[0015] Further, the output end of the first AD converter is connected to the input end of the data memory; the output end of the first DA converter is connected to the input end of the subtraction circuit unit; the output end of the data memory is connected to the input end of the first DA converter; the output end of the timing controller is respectively connected to the input ends of the first AD converter, the first DA converter, the data memory, the second AD converter, and the second DA converter; the output end of the signal amplifier is connected to the input end of the second AD converter.
[0016] Combining all the above technical solutions, the advantages and positive effects of the present invention are as follows: The analog signal output by the space camera detector of the present invention no longer uses high-resolution undifferentiated quantization, but undergoes dual AD quantization sampling. Among them, the AD1 quantization module is used for reference sampling. The signal processing module feeds the data of AD1 back to the front end of the analog signal through DA1 for subtraction. After the residual signal is amplified by the signal conditioning module, it is sent to the AD2 quantization module for non-linear quantization to enhance weak target signals. By comparing with the preset value and correcting the quantization parameters through iterative training, a substantial compression of the imaging detection data rate is finally achieved. This method has the characteristics of high sensitivity, strong real-time performance, and small data operation volume. After application, it can effectively reduce the data rate requirement of the space camera for detecting weak targets, and at the same time reduce the requirements for high-resolution AD or transmission quantization bits.
[0017] Compared with the traditional sampling method and the optical front-end compressive sampling scheme in recent years, this scheme can significantly reduce the data volume. Experimental results show that for imaging the same area, compared with the traditional sampling method, the space detection camera using this method has a dwell time of 10 ms, a detector array of 1024 * 1024 elements, and 2 spectral bands. Then the quantization bit rate of the traditional sampling method is about 3.4 Gbps, and after using this method, the quantization bit rate is reduced to 850 Mbps.
[0018] Comparison table between Table 1 and the prior art
[0019]
[0020] BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments of the present application. Obviously, the following described drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0022] Figure 1 It is a schematic structural diagram of the variable entropy compressive sampling system of the space camera provided by the embodiment of the present invention;
[0023] In the figure: 1. AD1 quantization device; 2. Signal conditioning device; 3. Signal processing device; 4. AD2 quantization device; 5. First AD converter; 6. First DA converter; 7. Subtraction circuit unit; 8. Signal amplification unit; 9. Data memory; 10. Timing controller; 11. Second AD converter; 12. Second DA converter. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0024] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0025] Aiming at the problems existing in the prior art, the present invention provides a variable entropy compression sampling system, control method, medium and terminal for a space camera. The present invention will be described in detail below with reference to the accompanying drawings.
[0026] As Figure 1 shown, the variable entropy compression sampling system for a space camera provided by an embodiment of the present invention includes: an AD1 quantization device 1, a signal conditioning device 2, a signal processing device 3, an AD2 quantization device 4, a first AD converter 5, a first DA converter 6, a subtraction circuit unit 7, a signal amplification unit 8, a data memory 9, a timing controller 10, a second AD converter 11, and a second DA converter 12.
[0027] In this embodiment, the AD1 quantization device 1 is connected to 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 to an AD2 quantization device 4.
[0028] The technical solution of the present invention will be further described below in conjunction with specific embodiments.
[0029] Embodiment 1
[0030] In this embodiment, the AD1 quantization device 1 is provided with a first AD converter 5 and a first DA converter 6, and the output end of the first AD converter 5 is connected to the input end of the first DA converter 6; the model of the first AD converter 5 is AD9204-20, a dual-channel AD converter, with a conversion rate of 20 MSPS and a resolution of 10 bits, and the model of the first DA converter 6 is AD9761, a dual-channel AD converter, with a resolution of 10 bits and a conversion rate of 40 MSPS.
[0031] In this embodiment, the signal conditioning device 2 is provided with a subtraction circuit unit 7 and a signal amplification unit 8, and the output end of the subtraction circuit unit 7 is connected to the input end of the signal amplification unit 8.
[0032] In this embodiment, the signal processing device 3 is provided with a data memory 9 and a timing controller 10.
[0033] In this embodiment, the AD2 quantization device 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 to the input end of the second AD converter 11; the model of the second AD converter 11 is AD9204-20, and the model of the second DA converter 12 is AD9761.
[0034] 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 to the input end of the subtraction circuit unit 7; the output end of the data memory 9 is connected to the input end of the first DA converter 6; the output end of the timing controller 10 is respectively connected to 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 amplifier is connected to the input end of the second AD converter 11.
[0035] The push-broom camera of the present invention images a target. The two analog signals output by the 1024-element infrared detector are first sent to the AD1 quantization module for AD conversion. A dual-channel medium-resolution AD is selected. The camera dwell time is set to 1 ms, and the exposure time does not exceed the dwell time, which is set to 500 us.
[0036] The data output by the AD1 quantization module is sent to the signal processing module. First, the current data is stored in the memory. This memory is built into the FPGA. The FPGA model is XQ4VSX55. The size of the memory matches the amount of information generated by the camera detector during one exposure. Each scan line stores 1024×10 bit; then when the data of the next exposure is sent over, the stored data is read out and sent to the first DA converter 6 of the AD2 quantization module.
[0037] After receiving the data, the first DA converter 6 of the AD2 quantization module converts it into an analog signal, which is fed back to the front end of the subtraction circuit unit 7 in the signal conditioning module for subtraction, and the subtracted residual signal is output. This signal has removed the slowly varying background.
[0038] The residual signal is filtered and non-linearly amplified in the signal conditioning device to adapt to the range of the AD2 quantization module; the amplified signal is sent to the AD2 quantization module for analog-to-digital conversion. AD2 can be a medium-low resolution DA. The AD9761 is selected. The voltage reference in the AD2 quantization module can be dynamically adjusted through the second DA to obtain the best target signal resolution, which is equivalent to changing the entropy of the signal for the output data; the data output by the AD2 quantization module has completed non-linear quantization, reducing the amount of data.
[0039] When obtaining the infrared image of the airport and performing line-by-line read-in analog quantization analysis, after adopting this method, for the image containing the aircraft target, in the scenario with more ground scenery and clouds, the single-spectrum data rate is reduced from 33 Mbps of traditional sampling at 16 bit to less than 5 Mbps, and in the cloudless and sunny weather, the data rate is reduced from 33 Mbps of traditional sampling at 16 bit to less than 1 Mbps.
[0040] Embodiment 2
[0041] In this embodiment, the AD1 quantization device 1 is provided with a first AD converter 5 and a first DA converter 6. The output end of the first AD converter 5 is connected to the input end of the first DA converter 6. The model of the first AD converter 5 is AD9204-40, which is a dual-channel AD converter with a conversion rate of 40 MSPS and a resolution of 10 bit. The model of the first DA converter 6 is AD9761, which is a dual-channel AD converter with a resolution of 10 bit and a conversion rate of 40 MSPS.
[0042] In this embodiment, the signal conditioning device 2 is provided with a subtraction circuit unit 7 and a signal amplification unit 8. The output end of the subtraction circuit unit 7 is connected to the input end of the signal amplification unit 8.
[0043] In this embodiment, the signal processing device 3 is provided with a data memory 9 and a timing controller 10.
[0044] In this embodiment, the AD2 quantization device 4 is provided with a second AD converter 11 and a second DA converter 12. The output end of the second DA converter 12 is connected to the input end of the second AD converter 11. The model of the second AD converter 11 is AD9204-40, and the model of the second DA converter 12 is AD9761.
[0045] 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 to the input end of the subtraction circuit unit 7; the output end of the data memory 9 is connected to the input end of the first DA converter 6; the output end of the timing controller 10 is respectively connected to 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 amplifier is connected to the input end of the second AD converter 11.
[0046] The staring camera of the present invention images a target. It uses a 1024×1024 element infrared detector. The 4 output analog signals are first sent to the AD1 quantization module for AD conversion. Dual-channel medium-resolution AD is selected. The camera dwell time is set to 10 ms, and the exposure time is adjustable and does not exceed the dwell time.
[0047] The data output by the AD1 quantization module is sent to the signal processing module. First, the current data is stored in the memory, which is built into the FPGA. The FPGA model is XC5VSX130T. The size of the memory matches the amount of information generated by the camera detector during one exposure. Each scan frame stores 1024×1024×14 bit. Then, when the data of the next exposure is sent over, the stored data is read out and sent to the first DA converter 6 of the AD2 quantization module.
[0048] After receiving data from the AD9761, the first DA converter 6 of the AD2 quantization module converts it into an analog signal, which is fed back to the front end of the subtraction circuit unit 7 in the signal conditioning module for subtraction, and the residual signal after subtraction is output. This signal has removed the slowly varying background.
[0049] The residual signal is filtered and non-linearly amplified in the signal conditioning device to adapt to the measurement range of the AD2 quantization module. The amplified signal is sent to the AD2 quantization module for analog-to-digital conversion. AD2 can be a medium- to low-resolution DA. The AD9761 is selected. The voltage reference in the AD2 quantization module can be dynamically adjusted by the second DA to obtain the best target signal resolution, which is equivalent to changing the entropy of the signal for the output data. The data output by the AD2 quantization module completes non-linear quantization and reduces the amount of data.
[0050] In ground experiments, an infrared camera is placed on the ground near an airport, and the actual scene is verified by observing the airport aircraft. After this method, for deep space images containing aircraft targets, in scenes with more clouds, the data rate is reduced from 3.4 Gbps of traditional sampling with 16 bits to less than 850 Mbps, and in cloudless and sunny weather, the data rate is reduced from 3.4 Gbps of traditional sampling with 16 bits to less than 100 Mbps.
[0051] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. Those of ordinary skill in the art can understand that the above devices and methods can be implemented using computer-executable instructions and / or included in processor control code, for example, such code is provided on a carrier medium such as a disk, CD, or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuits of programmable hardware devices such as very large scale integrated circuits or gate arrays, semiconductors such as logic chips and transistors, or programmable logic devices such as field programmable gate arrays, and can also be implemented by software executed by various types of processors, or can be implemented by a combination of the above hardware circuits and software such as firmware.
[0052] The above is only the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention by those skilled in the art in the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.
Claims
1. A variable entropy compression sampling system for a space camera, characterized in that, the variable entropy compression sampling system for the space camera is provided with: an AD1 quantization device; the AD1 quantization device is connected to 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 to 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 to 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 to the input end of the signal amplification unit; the signal processing device is provided with a data memory and a timing controller; characterized in that 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 to the input end of the second AD converter; the output end of the first AD converter is connected to the input end of the data memory; the output end of the first DA converter is connected to the input end of the subtraction circuit unit; the output end of the data memory is connected to the input end of the first DA converter; the output end of the timing controller is respectively connected to the input ends of the first AD converter, the first DA converter, the data memory, the second AD converter, and the second DA converter; the output end of the signal amplifier is connected to the input end of the second AD converter; A variable entropy compression sampling method for a space camera implementing the variable entropy compression sampling system for the space camera, the variable entropy compression sampling method for the space camera comprising: The data output by the AD1 quantization module is sent to the signal processing module, and the current data is stored in the memory. The memory is built into the FPGA, and the size of the memory matches the amount of information generated by one exposure of the camera detector. Each scan line stores 1024×10bit; then when the data of the next exposure is sent over, the data is read out and sent to the first DA converter of the AD1 quantization module. The first DA converter of the AD1 quantization module is connected to the first AD converter. The first AD converter is AD9761, and after receiving the data, it is converted into an analog signal and fed back to the front end of the subtraction circuit unit in the signal conditioning module for subtraction, and the subtracted residual signal is output. The residual signal is filtered and non-linearly amplified in the signal conditioning device, and the amplified signal is sent to the AD2 quantization module for analog-to-digital conversion. Dynamic adjustment is performed through the second DA to obtain the best target signal resolution, which is equivalent to changing the entropy of the signal for the output data; the data output by the AD2 quantization module completes the non-linear quantization.
2. The variable entropy compression sampling system for a space camera according to claim 1, characterized in that, The push-broom camera images the target. The two-way analog signals output by the 1024×1024 element infrared detector are first sent to the AD1 quantization module for AD conversion. Dual-channel medium-resolution AD is selected, the camera dwell time is set to 1ms, and the exposure time does not exceed the dwell time and is set to 500us.
3. A computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the processor performs the following steps: The data output by the AD1 quantization module is sent to the signal processing module and the current data is stored in a memory. The memory is built into the FPGA and its size matches the amount of information generated by one exposure of the camera detector. Each scan line stores 1024 × 10 bits. Then, when the data of the next exposure is sent over, the data is read out and sent to the first DA converter of the AD1 quantization module. The first DA converter of the AD1 quantization module is connected to the first AD converter. The first AD converter is AD9761. After the first AD converter receives the data, it is converted into an analog signal and fed back to the front end of the subtraction circuit unit in the signal conditioning module for subtraction, and the residual signal after subtraction is output. The residual signal is filtered and non-linearly amplified in the signal conditioning device. The amplified signal is sent to the AD2 quantization module for analog-to-digital conversion, and is dynamically adjusted through the second DA to obtain the best target signal resolution, which is equivalent to changing the entropy of the signal for the output data. The data output by the AD2 quantization module completes the non-linear quantization.