Methods, equipment, and media for delineating lander exhaust disturbance zones used in remote sensing.

Abstract

This invention relates to a method, device, and medium for delineating the exhaust gas disturbance zone of a lander for remote sensing detection. The method includes: acquiring remote sensing images before landing and multispectral images after landing, and performing preprocessing; drawing a time-series ratio image based on the preprocessed remote sensing images before landing and multispectral images after landing; and delineating the boundary of the disturbance zone based on the ratio change information extracted from the time-series ratio image. Compared with the prior art, this invention has the advantage of high accuracy in disturbance zone delineation.

Description

Technical Field

[0001] This invention relates to the field of remote sensing, and in particular to a method, device and medium for delineating the exhaust gas disturbance zone of a lander for remote sensing. Background Technology

[0002] Mars exploration, a crucial part of humanity's exploration of the universe, has made significant progress in recent years. With continuous advancements in exploration technology, our understanding of Mars is deepening. To gain a more comprehensive understanding of the Martian environment, scientists are constantly conducting Mars exploration missions and utilizing various probes for scientific research. The Mars lander is an indispensable part of these missions, its primary task being to safely deliver the probe to the Martian surface and conduct scientific exploration. The thin Martian atmosphere causes the lander's deceleration retrorockets to generate high-speed exhaust gases during descent, which can disturb the Martian surface. This disturbance can impact subsequent scientific exploration; therefore, it is necessary to analyze and assess the exhaust gas disturbances from the Mars lander.

[0003] Remote sensing technology, as an important means of studying the Earth's surface and celestial bodies, plays a crucial role in Mars exploration. By comparing high-resolution optical remote sensing images before and after the lander's descent, images of the lander's exhaust gases affecting the Martian regolith during the landing process can be extracted, thereby enabling the differentiation of disturbance zone characteristics and the delineation of disturbance zone boundaries. Currently, the disturbances generated by the lander on the Martian surface are mainly divided into two categories: (1) disturbances generated by the lander's exhaust gases affecting the Martian regolith during the landing phase; and (2) disturbances generated by a series of exploration activities conducted by the lander after landing affecting the Martian regolith.

[0004] The current method for delineating the disturbed area of ​​a Mars lander uses the difference in reflectivity between post-landing images and undisturbed areas to define the boundary. This method cannot accurately extract the disturbance characteristics of the lander on the Martian regolith, nor can it accurately delineate the boundary of the disturbed area. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method, device and medium for lander exhaust disturbance zone division with higher accuracy for remote sensing detection.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] According to a first aspect of the present invention, a method for delineating the exhaust gas disturbance zone of a lander is provided, comprising:

[0008] Acquire remote sensing images of the lander before landing and multispectral images after landing, and perform preprocessing;

[0009] Based on the pre-processed remote sensing images before landing and the post-landing multispectral images, a time-series ratio image is drawn, and the boundary of the disturbance area is delineated based on the ratio change information extracted from the time-series ratio image.

[0010] Preferably, the preprocessing includes:

[0011] Perform light and color homogenization, stitching and projection preprocessing on the remote sensing images before landing;

[0012] Radiometric correction and projection preprocessing were performed on the multispectral images after landing.

[0013] Preferably, the step of drawing a time-series ratio image based on the pre-processed remote sensing image before landing and the post-landing multispectral image specifically involves dividing the red band image in the pre-processed post-landing multispectral image by the pre-landing remote sensing image to obtain the time-series ratio image.

[0014] Preferably, the step of delineating the boundary of the disturbance region based on the ratio change information extracted from the time-series ratio image specifically involves:

[0015] Plot a straight line through the entire disturbance area on the time-series ratio image, extract the ratio on the line, and obtain the ratio change curve;

[0016] Select several representative ratio change curves to establish boundary standards. On the ratio change curves, select the points where the slope of the ratio change changes as the boundary points of the disturbance zone. The ratio change between adjacent boundary points is used as the characteristics of the disturbance zone.

[0017] The extracted boundary points of multiple disturbance regions are connected to form a closed curve, which serves as the boundary of the disturbance region.

[0018] Preferably, the boundary of the disturbance zone includes the boundary between the ordinary disturbance zone and the core disturbance zone, as well as the boundary between the core disturbance zone and the passivation influence zone.

[0019] Preferably, the method further includes: determining a passivation region and a region of interest for lander sampling based on the boundary of the disturbance region delineated using time-series ratio images; wherein, the passivation region is the area enclosed by the lander where the outer boundary of the passivation influence region, which is a fan-shaped region, extends in the opposite direction to the lander; and the region of interest is the area 1-3m away from the edge of the lander on the corresponding side of the lander.

[0020] Preferably, the method further includes verifying the passivation region and the region of interest used for lander sampling, specifically including:

[0021] False-color composite images are obtained by performing false-color synthesis on the preprocessed multispectral images after landing. Based on the defined boundaries of the disturbance area, discrete points are randomly selected in the core disturbance area, passivation area, region of interest, and passivation influence area, and the spectral values ​​of the discrete points are extracted.

[0022] Based on the spectral values ​​of discrete points, a scatter plot is drawn to extract and verify the spectral features of the perturbation region: if the spectral points are mixed but the number of mixed spectral points is within 20% of the total number of spectral points in the corresponding perturbation region, and if there are discrete spectral points but the number of discrete spectral points is within 10% of the total number of spectral points in the corresponding perturbation region, then the verification is passed; otherwise, the passivation region and region of interest are adjusted and optimized.

[0023] Preferably, the scatter plot is drawn based on the spectral values ​​of discrete points: the scatter plot is drawn with the difference in reflectance between the near-infrared band and the red band as the vertical axis and the reflectance of the green band as the horizontal axis.

[0024] Preferably, the spectral characteristics include the difference in reflectance between the near-infrared and red bands, and the reflectance in the blue-green bands.

[0025] According to a second aspect of the present invention, an electronic device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the program to implement any of the methods described above.

[0026] According to a third aspect of the invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements any of the methods described herein.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1) This invention obtains a time-series ratio image by processing remote sensing images before and after landing. A straight line passing through the entire disturbance zone is plotted on the time-series ratio image, and the ratio change curve is extracted. Points where the slope of the ratio change changes are selected as disturbance zone boundary points. Connecting multiple extracted disturbance zone boundary points into a closed curve serves as the boundary of the disturbance zone. This allows for a more accurate and reliable delineation of the lander exhaust disturbance zone based on the lander's landing characteristics. Accuracy evaluation shows that the boundary delineation error of the disturbance zone is <2m.

[0029] 2) This invention utilizes the boundary of the disturbance area delineated by time-series ratio images to determine the passivation area and the region of interest for lander sampling. Then, it uses spectral features extracted from multispectral images after lander landing to verify and optimize the passivation area and the region of interest for lander sampling. This solves the problem that time-series ratio images are difficult to distinguish small-scale disturbance areas. By distinguishing through spectral features, it can capture surface features at different wavelengths, providing richer information than monospectral images, enhancing the ability to identify disturbance areas, and enabling feature differentiation between small-scale disturbance areas and areas with relatively small differences.

[0030] 3) Image preprocessing, including radiometric correction, uniform lighting and color matching, stitching and projection, can significantly improve the quality and consistency of images. Radiometric correction ensures the accuracy of the spectral information of the image, uniform lighting and color matching ensures the uniformity of the brightness and color of the image, and stitching and projection ensure the spatial continuity and geometric accuracy of the image, ensuring that accurate information on the disturbance area can be extracted in subsequent operations. Attached Figure Description

[0031] Figure 1 Flowchart of the method for remote sensing detection and analysis of the impact of lander exhaust;

[0032] Figure 2 The images show the preprocessed disturbance areas before and after the lander's landing; (a) is the image before the lander's landing; and (b) is the image after the lander's landing.

[0033] Figure 3 Example image showing the location of the ratio change curve;

[0034] Figure 4 Extract example graphs for the ratio curve;

[0035] Figure 5 A diagram showing the boundary delineation results of the disturbance zone;

[0036] Figure 6 The result diagram shows the differentiation of spectral features. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0038] Example

[0039] like Figure 1 As shown in the embodiment, a method for delineating the exhaust gas disturbance zone of a lander for remote sensing is provided, including:

[0040] S1. Acquire remote sensing images of the lander before landing and multispectral images after landing, and perform preprocessing.

[0041] The preprocessing includes homogenizing, color homogenizing, stitching, and projection preprocessing of the pre-landing remote sensing images, and radiometric correction and projection preprocessing of the post-landing multispectral images. Radiometric correction ensures the accuracy of the image's spectral information, homogenizing ensures the uniformity of the image's brightness and color, and stitching and projection ensure the spatial continuity and geometric accuracy of the image, guaranteeing that subsequent operations can extract accurate information about disturbed areas.

[0042] S2. Based on the pre-processed remote sensing images before landing and the multispectral images after landing, a time-series ratio image is drawn. Based on the ratio change information extracted from the time-series ratio image, the boundary of the disturbance area is delineated, specifically including:

[0043] S21. Divide the red band image in the pre-processed post-landing multispectral image by the remote sensing image before landing to obtain the time-series ratio image.

[0044] S22. Draw a straight line through the entire disturbance area on the time-series ratio image, extract the ratio on the straight line, and obtain the ratio change curve;

[0045] S23. Select three representative ratio change curves to formulate boundary standards. Select the point on the ratio change curve where the slope of the ratio change changes as the boundary point of the disturbance zone. The ratio change between adjacent boundary points is used as the characteristic of the disturbance zone. Then select other boundary points according to the boundary standards.

[0046] S24. Connect the extracted boundary points of the disturbance region into a closed curve, which serves as the boundary of the disturbance region, specifically:

[0047] Connect the extracted boundary points of multiple disturbance regions into a closed curve to delineate the boundaries of the ordinary disturbance region, the core disturbance region, the passivation influence region, and the maximum range of the passivation region.

[0048] S3. Based on the boundary of the disturbance area delineated using time-series ratio images, determine the passivation area and the region of interest for lander sampling; wherein, the passivation area is the region enclosed by the lander after the outer boundary of the fan-shaped passivation influence area extends in the opposite direction; and the region of interest is the area 1-3m away from the edge of the lander on the corresponding side.

[0049] This embodiment also includes verifying the passivation region and the region of interest used for lander sampling, specifically including:

[0050] S31. Acquire multispectral images of the lander after landing and perform preprocessing;

[0051] S32. Perform false-color synthesis on the preprocessed post-landing multispectral image to obtain a false-color composite image. Based on the defined boundaries of the disturbance area, extract the spectral features of each discrete point in each disturbance area (the indistinguishable passivation area and region of interest, as well as the adjacent core disturbance area and passivation influence area). The spectral features include the difference in reflectance between the near-infrared (NIR) and red band (RED) bands, as well as the reflectance in the blue-green band (BG).

[0052] Two spectral indices are obtained by mathematically processing the spectral values. The difference between the near-infrared band (NIR) and the red band (RED) is used as one spectral index, and the blue-green band (BG) is used as the other spectral index. Scatter plots are drawn on the vertical and horizontal axes, respectively. Spectral points with the same spectral characteristics will cluster together. Finally, the spectral points in the selected perturbation region do not mix significantly, thus achieving spectral differentiation.

[0053] S33. Based on the spectral characteristics of discrete points, draw a scatter plot (with the difference in reflectance between near-infrared and red bands as the vertical axis and the reflectance of blue-green bands as the horizontal axis) to verify the perturbation region: if spectral points are mixed but the number of mixed spectral points is within 20% of the total number of spectral points in the corresponding perturbation region, and discrete spectral points exist but the number of discrete spectral points is within 10% of the total number of spectral points in the corresponding perturbation region, then the verification is passed; otherwise, the passivation region and region of interest are adjusted and optimized.

[0054] The lander exhaust disturbance zone delineation method designed in this invention for remote sensing can be applied to different high-resolution Mars remote sensing data, such as High Resolution Imaging Science Experiment (HiRISE) and High Resolution Imaging Camera (HiRIC). Radiometric correction needs to be specifically considered according to the characteristics of the data source.

[0055] This embodiment is based on the pre-landing images of Tianwen-1 acquired by HiRIC aboard the Tianwen-1 spacecraft launched by the China National Space Administration (CNSA) and the post-landing images of Tianwen-1 acquired by NASA's Mars Reconnaissance Orbiter HiRISE. No radiometric correction was performed on the HiRIC images in this embodiment. Figure 2 The images show the preprocessed images of the disturbed area before and after the lander's landing; (a) is the image before the lander landed; and (b) is the image after the lander landed. It is clear that a significant change in light intensity occurred in the landing area before and after the Tianwen-1 lander's landing.

[0056] For areas where the background was not disturbed by landing exhaust, the image ratio before and after landing was 8.3×10. -5 ~8.4×10 -5 Therefore, 8.3 × 10⁻⁶ was chosen. -5This serves as the boundary between the ordinary disturbance region and the core disturbance region. Within the disturbance region, the ratio gradually decreases, and the closer to the center of the disturbance region, the lower the ratio. During this decrease, the ratio starts from 8.3 × 10⁻⁶. -5 It decreased to 8.1×10 -5 The process is 8.1×10 -5 It decreased to 7.8 × 10 -5 The process is slower, and the slope is smaller. Therefore, we take 8.1 × 10⁻⁶. -5 This ratio serves as the boundary between the ordinary disturbance region and the core disturbance region. Therefore, when the ratio of a region is 8.1 × 10⁻⁶, -5 ~8.3×10 -5 Between these two points, this area is the ordinary disturbance zone. The boundary between the core disturbance zone and the passivation influence zone is very clear. From the core disturbance zone to the passivation influence zone, the ratio shows a significant jump. Therefore, the point where the ratio shows a significant jump is selected as the boundary between the passivation influence zone and the core disturbance zone.

[0057] In summary, this embodiment selects a ratio of 8.1 × 10⁻⁶. -5 ~8.3×10 -5 The area is a normal disturbance zone, with a ratio of 8.1 × 10⁻⁶. -5 The region where the ratio jumps is the core disturbance region, and the region where the ratio jumps significantly within the core disturbance region is the passivation influence region. Figure 3 Example image showing the location of the ratio change curve; Figure 4 Extract example graphs for the ratio curve; Figure 5 The result of boundary delineation for the disturbance zone.

[0058] For spectral feature extraction, experiments showed that subtracting the red band (RED) from the near-infrared band (NIR) as one spectral index, and using the blue-green band (BG) as another, can effectively distinguish spectral points. The spectral points in the four perturbation regions used for spectral differentiation—the core perturbation region, the passivation region, the passivation-affected region, and the region of interest (ROI)—are well clustered within their respective ranges, with only minor mixing observed in the passivation and ROI regions. Specifically, one point was mixed in the passivation region, accounting for 16.7% of all spectral points therein; and one point was mixed in the ROI, accounting for 2.6% of all spectral points therein. Both are less than 20%, meeting the requirements for successful spectral differentiation. Figure 6 The result diagram shows the differentiation of spectral features.

[0059] The electronic device of this invention includes a central processing unit (CPU), which can perform various appropriate actions and processes according to computer program instructions stored in read-only memory (ROM) or loaded from a storage unit into random access memory (RAM). The RAM may also store various programs and data required for device operation. The CPU, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0060] Multiple components in the device are connected to the I / O interface, including: input units such as keyboards and mice; output units such as various types of displays and speakers; storage units such as disks and optical discs; and communication units such as network interface cards (NICs), modems, and wireless transceivers. The communication unit allows the device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0061] The processing unit executes the various methods and processes described above, such as methods S1 to S3. For example, in some embodiments, methods S1 to S3 may be implemented as computer software programs tangibly contained in a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program may be loaded and / or installed on the device via ROM and / or a communication unit. When the computer program is loaded into RAM and executed by the CPU, one or more steps of methods S1 to S3 described above may be performed. Alternatively, in other embodiments, the CPU may be configured to execute methods S1 to S3 by any other suitable means (e.g., by means of firmware).

[0062] The functions described above in this document can be performed at least in part by one or more hardware logic components. For example, exemplary types of hardware logic components that can be used, without limitation, include: field programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload programmable logic devices (CPLDs), and so on.

[0063] The program code used to implement the methods of the present invention can be written in any combination of one or more programming languages. This program code can be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0064] In the context of this invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0065] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for dividing the exhaust gas disturbance zone of a lander, characterized in that, include: Acquire remote sensing images of the lander before landing and multispectral images after landing, and perform preprocessing; Based on the pre-processed remote sensing images before landing and the multispectral images after landing, a time-series ratio image is drawn, and the boundary of the disturbance area is delineated based on the ratio change information extracted from the time-series ratio image. The step of plotting a time-series ratio image based on the pre-processed remote sensing image before landing and the post-landing multispectral image is as follows: divide the red band image in the pre-processed post-landing multispectral image by the remote sensing image before landing to obtain the time-series ratio image. The step of delineating the boundary of the disturbance region based on the ratio change information extracted from the time-series ratio image is as follows: Plot a straight line through the entire disturbance area on the time-series ratio image, extract the ratio on the line, and obtain the ratio change curve; Select several representative ratio change curves to establish boundary standards. On the ratio change curves, select the points where the slope of the ratio change changes as the boundary points of the disturbance zone. The ratio change between adjacent boundary points is used as the characteristics of the disturbance zone. Connect the extracted boundary points of multiple disturbance regions into a closed curve to serve as the boundary of the disturbance region; The boundary of the disturbance region includes the boundary between the ordinary disturbance region and the core disturbance region, as well as the boundary between the core disturbance region and the passivation influence region; Based on the boundary of the disturbance area delineated using time-series ratio images, a passivation area and a region of interest for lander sampling are determined; wherein, the passivation area is the region enclosed by the lander, whose outer boundary is a fan-shaped passivation influence area extended in the opposite direction; and the region of interest is the area 1-3m away from the edge of the lander on the corresponding side.

2. The method for dividing the lander exhaust gas disturbance zone according to claim 1, characterized in that, The preprocessing includes: Perform light and color homogenization, stitching and projection preprocessing on the remote sensing images before landing; Radiometric correction and projection preprocessing were performed on the multispectral images after landing.

3. The method for dividing the lander exhaust gas disturbance zone according to claim 1, characterized in that, The method further includes verifying the passivation region and the region of interest used for lander sampling, specifically including: False-color composite images are obtained by performing false-color synthesis on the preprocessed multispectral images after landing. Based on the defined boundaries of the disturbance area, discrete points are randomly selected in the core disturbance area, passivation area, region of interest, and passivation influence area, and the spectral values ​​of the discrete points are extracted. Scatter plots are drawn based on the spectral values ​​of discrete points, and spectral features of the perturbation region are extracted and verified: if spectral points are mixed but the number of mixed spectral points is within 20% of the total number of spectral points in the corresponding perturbation region, and discrete spectral points exist but the number of discrete spectral points is within 10% of the total number of spectral points in the corresponding perturbation region, then the verification is passed; otherwise, the passivation region and region of interest are adjusted and optimized.

4. The method for dividing the lander exhaust gas disturbance zone according to claim 3, characterized in that, The scatter plot is drawn based on the spectral values ​​of discrete points: the difference in reflectance between the near-infrared band and the red band is plotted on the vertical axis, and the reflectance of the green band is plotted on the horizontal axis.

5. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the program, it implements the method as described in any one of claims 1 to 4.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the method as described in any one of claims 1 to 4.

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