A method and system for classifying the degradation of Martian impact craters based on a combination of morphology and erosion characteristics.
By mapping the outlines of Martian impact craters and selecting ten descriptive factors, the complexity and inaccuracy of Martian impact crater degradation classification were resolved, achieving an efficient and universally applicable classification of impact crater degradation levels.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-24
- Publication Date
- 2026-03-10
AI Technical Summary
Existing technologies are difficult to classify the degree of degradation of Martian impact craters effectively, simply, and efficiently. They are affected by the irregularity of impact crater morphology and the heterogeneity of terrain, and the classification methods are not very universal.
By acquiring high-resolution remote sensing images of Mars, the three-point circle method was used to draw the outline of the impact crater, excluding secondary impact craters. Ten descriptive factors, such as impact crater ejecta, crater rim gap, and crater rim sharpness, were selected. Based on morphology and erosion characteristics, the degree of impact crater degradation was divided into seven levels.
It enables accurate classification of the degradation level of Martian impact craters, avoids complex calculations, improves the accuracy and universality of the classification, and is not limited by terrain heterogeneity and regional selection.
Smart Images
Figure CN117078643B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the fields of planetary remote sensing and planetary geomorphology, and particularly relates to a method and system for classifying the degradation of Martian impact craters by integrating morphology and erosion characteristics. Background Technology
[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.
[0003] Small impact craters are a major surface feature across all Martian terrains, and their preservation and morphology are highly sensitive to the composition, intensity, and erosion processes of Martian strata. Therefore, the shape and characteristics of Martian impact craters can reflect the processes of Martian surface erosion and degradation, thus providing information for understanding the geological conditions, climate background, and tectonic evolution of the Martian surface.
[0004] Fresh impact craters on rocky planets typically exhibit simple, regular bowl-like shapes. However, over time, due to physical and chemical weathering (such as wind, gravity, and water / ice), they gradually degrade, revealing diverse morphological features. Because of the complexity of the pre-impact topography and the irregularity of the cratering process, using geometric features to classify the degree of impact crater degradation is usually not ideal. Furthermore, during degradation, ejected rocks and crater edges disappear due to gravity, impact, and wind erosion, while the crater interior also experiences rim stripping and wind-borne deposition and filling of the crater floor.
[0005] Impact crater classification is crucial for inferring the geological processes and climate history during the formation and evolution of Martian geological units, serving as a starting point for analyzing Martian lithomorphology, estimating the age of the Martian surface, and retrieving the thickness of the volcanic reef. The inventors discovered that previous methods for classifying the degree of impact crater degradation based on data from previous Mars missions mainly encountered the following three problems:
[0006] (1) Existing technologies for establishing degradation classification standards for impact craters are mainly based on the geometric characteristics of impact craters (such as the degree of edge damage), and the results are affected by the irregularity of the morphological characteristics of impact craters and the heterogeneity of the terrain.
[0007] (2) Existing technologies require extensive and complex calculations of the geometric features of impact craters and must be combined with high-precision digital terrain models. The results are easily affected by factors such as image resolution, imaging conditions and algorithm theory, and cannot establish a simple and efficient classification method.
[0008] (3) Existing methods for classifying impact craters vary depending on the region selected, and their universality is not high.
[0009] Therefore, establishing a universal standard for classifying the degradation of Martian impact craters is of great significance. Summary of the Invention
[0010] To overcome the shortcomings of the existing technologies, this invention analyzes the degradation sequence of impact craters in the Martian surface research area and proposes a comprehensive method and system for classifying Martian impact crater degradation based on morphological and erosion characteristics. This method classifies the degree of impact crater degradation solely based on morphological characteristics, eliminating the need for extensive and complex calculations. It is unaffected by the heterogeneity of the pre-impact terrain and the irregularity of impact crater morphology, providing impact crater classification data for subsequent inference of surface processes and climate history in the research area.
[0011] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:
[0012] The first aspect of this invention provides a method for classifying the degradation of Martian impact craters by integrating morphology and erosion characteristics.
[0013] A method for classifying Martian impact crater degradation based on a combination of morphology and erosion characteristics includes the following steps:
[0014] Acquire high-resolution remote sensing images of Mars, use the three-point circle method to draw the outline of impact craters, and identify impact craters in the study area.
[0015] Secondary impact craters were excluded from the study area;
[0016] Ten descriptive factors were selected to describe the impact craters in the study area: impact crater ejecta, crater rim gap, crater rim sharpness, crater rim damage degree, crater bottom filling material, sand ripple area ratio, crater bottom elevation variation coefficient, depth-to-diameter ratio, crater rim roughness, and abundance of superimposed impact craters.
[0017] An analysis of the grading criteria for impact crater degradation based on ten descriptive factors was conducted, classifying the degradation process of Martian impact craters into seven degradation levels.
[0018] The second aspect of the present invention provides a degradation classification system for Martian impact craters that integrates morphology and erosion characteristics.
[0019] A comprehensive classification system for Martian impact crater degradation, based on both morphology and erosion characteristics, includes:
[0020] The impact crater outline drawing module is configured to: acquire high-resolution remote sensing images of Mars, draw impact crater outlines using the three-point circle method, and identify impact craters in the study area.
[0021] The secondary impact crater exclusion module is configured to exclude secondary impact craters in the study area.
[0022] The descriptor selection module is configured to select ten descriptor factors to describe the impact craters in the study area: impact crater ejecta, crater rim gap, crater rim sharpness, crater rim damage degree, crater bottom filling material, sand ripple area ratio, crater bottom elevation variation coefficient, depth-to-diameter ratio, crater rim roughness, and abundance of superimposed impact craters.
[0023] The grading module is configured to analyze the grading criteria for impact crater degradation based on ten descriptive factors, and to divide the degradation process of Martian impact craters into seven degradation levels.
[0024] A third aspect of the present invention provides a computer-readable storage medium having a program stored thereon that, when executed by a processor, implements the steps in the method for classifying the degradation of Martian impact craters by integrating morphology and erosion characteristics as described in the first aspect of the present invention.
[0025] The fourth aspect of the present invention provides an electronic device including a memory, a processor, and a program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps in the method for classifying the degradation of Martian impact craters by integrating morphology and erosion features as described in the first aspect of the present invention.
[0026] The above one or more technical solutions have the following beneficial effects:
[0027] This invention provides a method and system for classifying Martian impact crater degradation by integrating morphology and erosion characteristics. It involves selecting at least three crater rim peak positions to draw the crater outline, accurately identifying and vectorizing impact craters in the study area. Secondary impact craters in the study area are excluded based on differences in morphology and distribution between primary and secondary impact craters, ensuring the accuracy of the results. Based on the morphology and erosion characteristics exhibited during crater degradation, ten factors are selected, including impact crater ejecta, crater rim gaps and sharpness, crater bottom filling material, and the abundance of superimposed impact craters, to classify and describe degraded impact craters.
[0028] The method provided by this invention enables the classification of impact crater degradation based solely on morphological features, without requiring extensive and complex calculations. It is unaffected by the heterogeneity of the pre-impact terrain and the irregularity of the impact crater's morphological features. Furthermore, the impact crater classification criteria are not limited by regional selection, and the classification criteria have a high degree of universality.
[0029] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0031] Figure 1 This is a schematic diagram showing the classification results of impact craters of levels 1 to 7 in the study area.
[0032] Figure 2 This is a spatial distribution map of impact craters in the study area, categorized by color coding.
[0033] Figure 3 This is a flowchart of the method in the first embodiment.
[0034] Figure 4 This is a system structure diagram of the second embodiment. Detailed Implementation
[0035] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0036] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.
[0037] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.
[0038] The overall concept proposed in this invention is as follows:
[0039] Impact craters within the same geological unit on the Martian surface have undergone similar geological processes and erosion evolution. Impact craters with the same degree of degradation will exhibit similar morphological variations and erosion characteristics. Therefore, by combining morphological and erosion characteristics, the degree of degradation of impact craters on the Martian surface can be accurately identified and classified, thereby establishing a reliable method for grading the degree of impact crater degradation.
[0040] Example 1
[0041] This embodiment discloses a method for classifying the degradation of Martian impact craters by combining morphology and erosion characteristics.
[0042] like Figure 3 As shown, the method for classifying the degradation of Martian impact craters by combining morphology and erosion characteristics includes the following steps:
[0043] Acquire high-resolution remote sensing images of Mars, use the three-point circle method to draw the outline of impact craters, and identify impact craters in the study area.
[0044] Secondary impact craters were excluded from the study area;
[0045] Ten descriptive factors were selected to describe the impact craters in the study area: impact crater ejecta, crater rim gap, crater rim sharpness, crater rim damage degree, crater bottom filling material, sand ripple area ratio, crater bottom elevation variation coefficient, depth-to-diameter ratio, crater rim roughness, and abundance of superimposed impact craters.
[0046] An analysis of the grading criteria for impact crater degradation based on ten descriptive factors was conducted, classifying the degradation process of Martian impact craters into seven degradation levels.
[0047] Tianwen-1 was launched in July 2020, successfully entered Mars orbit in February 2021, and landed on the southern part of Utopia Planitia on the Martian surface on May 15. The landing site is located at... Figure 2 It was marked with a red five-pointed star. On May 22 of the same year, the "Zhurong" Mars rover safely departed from the landing platform, reached the Martian surface, and began its exploration. Figure 2 As shown, the study area for this invention is a 134-square-kilometer region surrounding the Mars rover "Zhurong". Images obtained using the High Resolution Imaging Science Experiment Camera (HiRISE) have a resolution of approximately 0.25 meters per pixel. This invention selects HiRISE images covering the study area to identify the original impact craters and classify their degree of degradation.
[0048] Figure 1 The image shows the classification of impact craters from level 1 to 7 within the study area, with the base map being a high-resolution HiRISE image of Mars. Some morphological features (descriptive factors) are marked with white arrows in the image.
[0049] Figure 2 The image shows the spatial distribution of impact crater classifications by color coding within a study area of approximately 134 square kilometers (HiRISE images ESP_069665_2055_RED and ESP_069876_2055_RED), with different colored crater outlines corresponding to different impact crater classifications. The location of the Zhurong rover is indicated by a red pentagram.
[0050] Specifically, it includes the following steps:
[0051] Step 1: Identification and mapping of impact craters in the study area based on Mars imagery and topographic data;
[0052] Impact craters in the study area were identified using high-resolution Mars remote sensing imagery. Assuming the resolution of the high-resolution Mars remote sensing imagery is r meters per pixel, all impact craters in the study area with a diameter greater than or equal to 3 × r meters were mapped (a minimum of three pixels was used to determine the diameter of each crater). A three-point circle method was used, selecting the three apexes of the crater's edge to draw its outline. If the crater edges in the study area lacked obvious peaks or were difficult to detect using high-resolution imagery, the crater boundaries were defined using the slope inflection points between the crater edge and the surrounding area, based on Digital Elevation Model (DEM) data.
[0053] Furthermore, secondary impact craters in the study area need to be excluded. When a large primary impact crater forms, the smaller impact craters formed by ejecta from the impact event landing on the Martian surface are defined as secondary impact craters. Due to the smaller impact angle and force, secondary impact craters are smaller in scale and shallower in depth, with a depth-to-diameter ratio (t) smaller than the diameter ratio of Martian impact craters (generally around 0.1). Because secondary impact craters involve oblique impacts, their ellipticity (e) is generally larger. Therefore, impact craters in the study area with a depth-to-diameter ratio t <= 0.07 and an ellipticity e >= 1.2 are considered secondary impact craters. Secondary impact craters exhibit inconsistent morphological features and degradation processes with primary impact craters; therefore, during identification, visual interpretation is used to exclude secondary impact craters that exist in chain-like, cluster-like, or other aggregated forms.
[0054] Step 2: Selection of descriptive factors for impact crater morphology features in the study area;
[0055] When a meteorite or small celestial body impacts the Martian surface, it creates a fresh impact crater with a flat-topped cone or bowl shape and sharp rims. From the outside in, it consists of three parts: the rim, the walls, and the floor. The impact process also excavates a large amount of coarse and fine-grained material and rocks from the Martian surface, which mix and scatter around the crater, forming a sputtering blanket with bright albedo. Subsequently, under the erosive action of surface processes such as wind, sand, volcanoes, glaciers, rivers, and frost, the various parts inside and outside the impact crater undergo a series of degradations. For example, the crater cavity gradually becomes flat, its depth decreases, and its shape changes from a bowl-shaped or flat-bottomed cone to a shallow concave shape. Due to wind erosion and the gravity of the slopes, the crater edges are gradually eroded, creating gaps and gaps, resulting in a smoother overall shape, reduced height, and wider width. The bright texture of the sputtering blanket gradually diminishes, becoming the same color as the surrounding area. The rocks and coarse-grained material within the sputtering blanket gradually break down, become smaller, and disappear due to weathering. As the crater rim degrades, the material surrounding the impact crater, along with the eroded and collapsed crater walls and rim material, gradually moves towards and fills the crater floor, then smooths and hardens. Over time, new impact craters (called superimposed impact craters) are gradually superimposed on the original impact crater, and the abundance of superimposed impact craters gradually increases, while their degree of degradation gradually intensifies.
[0056] Based on the main morphological and erosion characteristics during the formation and degradation of impact craters, this method selects ten factors to describe and analyze the degradation levels of impact craters in the study area. Assuming the study area is divided into n degradation levels, with i representing the degradation level, then i = 1, 2, ..., n. The factors for the i-th degradation level are: impact crater ejecta, crater rim gap, and crater rim sharpness A. i Degree of damage to the pit edge (P) i Pit bottom filler, sand corrugation area ratio S i Coefficient of variation of pit bottom elevation V i Aspect Ratio T i Roughness of pit edge i and the abundance of superimposed impact craters N i The following is a detailed description:
[0057] Crater ejecta consists of material excavated from the Martian surface during an impact event and deposited on the outer edge of the crater. They are generally distributed radially. The most primitive impact craters exhibit low albedo stripes. Because the earliest stages of impact crater formation involve relatively rapid degradation, impact crater ejecta are found around fresher impact craters.
[0058] Crater edge gaps are the cracks and gaps that appear on the crater edge after an impact event due to erosion. As the degree of degradation increases, the crater edge gaps gradually increase.
[0059] Crater edge sharpness describes the sharpness of the impact crater edge. As the degree of degradation increases, the crater edge sharpness gradually decreases. Crater edge sharpness is divided into four levels: Level 1 is the sharpest, Level 2 is relatively sharp with a clear outline, Level 3 is a smooth crater edge, and Level 4 is a completely destroyed crater edge with a very smooth surface.
[0060] The degree of crater edge damage is the percentage of the crater edge gap length to the crater edge perimeter. As the degree of degradation increases, the gap between crater edge gaps and the number of superimposed craters increase, resulting in a gradual increase in the degree of crater edge damage. The degree of crater edge damage can be divided into five ranges: the first range is 0 to 5%, the second range is 5% to 15%, the third range is 15% to 25%, the fourth range is 25% to 50%, and the fifth range is 50% and above.
[0061] The crater bottom fill consists of impact debris ejected to the bottom of the crater during its formation or material that subsequently moved to the bottom under Martian winds and erosion. The bottoms of the most degraded impact craters are almost completely filled.
[0062] The sand ripple area ratio is the percentage of the sand ripple area at the bottom of the impact crater to the total area of the crater bottom. Sand ripples are formed when sand-sized material migrates to the bottom of the impact crater. A large amount of sediment at the bottom of the crater shows a dense ripple pattern. The sand ripple area ratio can fluctuate within four ranges: the first range is 0% to 20%, the second range is 20% to 40%, the third range is 40% to 60%, and the fourth range is 60% and above. Over time, sand ripples develop high albedo, become wider, have incomplete structures, decrease in number, or even disappear completely.
[0063] The coefficient of variation of the crater bottom elevation is the ratio of the standard deviation of the crater bottom elevation to the average elevation of the crater bottom. The coefficient of variation of the crater bottom elevation can fluctuate within three intervals: the first interval is 10% to 20%, the second interval is 20% to 40%, and the third interval is 30% to 60%. Over time, the shape of the impact crater bottom has changed significantly, and the elevation characteristics of the crater bottom have gradually become more uniform and gentle, and the coefficient of variation of the crater bottom elevation has also decreased accordingly.
[0064] The depth-to-diameter ratio is the ratio of the maximum elevation difference between the top and bottom of an impact crater to the diameter of the crater. Due to the filling of aeolian sediments, meteorite impacts, gravity, and the burial by ejecta, the depth-to-diameter ratio decreases over time. When the depth-to-diameter ratio is less than 0.01, the impact crater is considered completely filled.
[0065] Crater edge roughness is the ratio of the actual perimeter of the crater edge to the ideal circumference of the crater edge (the circle defined by three points on the crater edge during drawing). The roughness of the freshest impact crater edge is close to 1. As the degree of degradation increases, the crater edge gradually becomes rougher due to factors such as gravity and wind erosion. At the highest degradation level, the edge is almost completely eroded, appearing shallowly concave and nearly circular. Therefore, the roughness of impact crater edges generally shows a trend of first increasing and then decreasing. Crater edge roughness can be divided into four intervals: the first interval is 0.9 to 1.1, the second interval is 1.1 to 1.3, the third interval is 1.2 to 1.4, and the fourth interval is 1.3 to 1.5.
[0066] The abundance of superimposed impact craters refers to the gradual superposition of new impact craters on existing ones, with the abundance of superimposed impact craters gradually increasing and their degradation becoming more pronounced. Since the abundance of impact craters with different diameters is not comparable, impact craters with diameters ranging from 90 to 110 meters were used as the research object. The abundance of superimposed impact craters was divided into four intervals: the first interval is 0 to 3, the second interval is 3 to 8, the third interval is 5 to 10, and the fourth interval is 8 and above.
[0067] Step 3: Establishment of a grading standard for the degree of degradation of Martian impact craters;
[0068] Based on the ten descriptive factors selected above, the grading criteria for impact crater degradation were analyzed. According to the preservation status and morphological characteristics of each mapped impact crater, the degradation process of Martian impact craters was divided into seven degradation levels (n=7). These were named impact craters from level 1 to level 7, with level 1 being the freshest and level 7 being the most degraded.
[0069] The degradation levels of impact craters from level 1 to 4 are primarily classified based on the condition of the crater's rim and the sand ripple pattern at the bottom. Level 1 represents the ideal, pristine (freshest) state of the impact crater. A level 1 impact crater is bowl-shaped or flat-bottomed cone-shaped, with a bottom filled with dark sand. S1 belongs to the first interval, and V1 belongs to the third interval. A level 1 impact crater exhibits significant ejecta, with sand ripples and well-preserved rocks within the ejecta blanket. The crater's perimeter displays clear low-albedo radiation streaks. R1 belongs to the first interval. A level 1 impact crater has a complete, sharp, regularly circular rim without any gaps. A1 belongs to the first level, and P1 = 0. There are no superimposed impact craters on it, N1 = 0, and the rim height is relatively high, T1 = 0.1.
[0070] Class 2 impact craters are characterized by well-defined rims and a certain height (0.07 ≤ T2 < 0.09). The rims are regular and continuous without gaps. A2 belongs to the second class, P2 to the first interval, and R2 to the second interval. Class 2 impact craters exhibit significant ejecta, with the ejecta blanket containing continuous rock / non-rock material. Craters with diameters of 30-60 meters may not contain rock in their ejecta. Compared to Class 1 craters, Class 2 impact craters show numerous, clearly defined sand ripples on the bottom, with a sub-meter to meter-scale structure and a dense distribution. S2 belongs to the fourth interval. Simultaneously, the undulating topography caused by the sand ripples places V2 in the third interval. A small number of superimposed impact craters are occasionally found on the ejecta blanket, rim, and walls. N2 is within the first interval.
[0071] Class 3 impact craters have become shallower due to continuous sediment accumulation caused by gravity erosion and wind transport (T3 < 0.08). However, high-reflectivity sand ripples still appear on the crater floor, though their abundance is lower than that of Class 2 craters. S3 belongs to the second region, and V3 is also within the second region. While the edges of Class 3 impact craters remain well-defined, their sharpness is reduced and some erosion gaps appear. A3 belongs to the third region, P3 to the first region, and R3 to the third region. There are more superimposed impact craters than in Class 2 craters, with N3 belonging to the second region.
[0072] The rims of Level 4 impact craters gradually degrade and their height decreases (0.04 ≤ T4 < 0.06). Compared to Level 3 craters, they exhibit more gaps and notches. A4 is the third region, P4 is the second region, and R4 is the fourth region. Bright sand ripples are visible outside the crater rim, but only a few are present. The sand ripples disappear at the crater bottom. S4 and V4 belong to the first region. From Level 2 to Level 4, the sand ripple structure gradually increases in size, while its abundance gradually decreases. Furthermore, smooth filling completely covers the bottom of the impact crater, making sand ripples difficult to observe. The density of superimposed impact craters further increases compared to Level 3, with N4 being the second region.
[0073] The degradation levels of impact craters 5 to 7 are primarily determined by the morphology of the crater margins and the abundance of superimposed impact craters. Scale 5 craters exhibit significant erosion at their margins, with the margin height decreasing further compared to scale 4 (0.03 ≤ T5 < 0.05). More fissures and gaps appear at the margins, and the shape becomes incomplete. A5 is scale 3, P5 and R5 are in the third interval. Scale 5 craters are morphologically characterized by a depression with bright edges and a dark interior. The crater floor is primarily filled with smooth sandy material. S5 and V5 are in the first interval, and the fill retains clearly defined superimposed impact craters, indicating that the fill has hardened. Furthermore, the superimposed impact craters at the bottom of scale 5 craters become denser and more degraded. N5 is in the third interval, where the rock within the ejecta blanket has been completely weathered and disappeared.
[0074] The rim of the Class 6 impact crater is almost completely destroyed, with the degree of rim damage increasing accordingly. A6 is Class 4, P6 is in the fourth region, R6 is in the second region, 0.02 ≤ T6 < 0.04, the crater interior is very smooth, completely lacking the impact structure of ejecta, S6 = 0, V5 is in the first region, visually interpreted as a sandy depression. The slightly raised rim remnants still have a small amount of sand ripples on the outside. Furthermore, the abundance of superimposed small impact craters is greater than that of Class 5, and N6 belongs to the fourth region.
[0075] Level 7 impact craters are the most degraded in the study area, with their edges almost completely eroded. A7 is Level 4, P7 is the fifth interval, 0.01 ≤ T7 < 0.03, and visual interpretation only reveals a blurry, nearly circular structure. R7 is the first interval. These are typically shallow depressions with flat bottoms; as degradation deepens, the terrain lacks significant undulations. V7 is the first interval, and S7 = 0. If subsequent impact events are sufficiently intense, the shape of Level 7 impact craters may be distorted into irregular shapes (such as sub-circular), with N7 being the fourth interval.
[0076] In practical implementation, this embodiment first identifies and maps the original impact craters in the study area with a diameter greater than or equal to 20 meters. For example... Figure 2As shown, the circles of different colors represent the identified impact craters. In this embodiment, a total of 2,625 impact craters were identified in the study area.
[0077] Then, through visual interpretation using ten descriptive factors and morphological features, the 2,625 identified impact craters were divided into seven degradation levels, including one Class 1 impact crater, 63 Class 2 impact craters, 123 Class 3 impact craters, 137 Class 4 impact craters, 225 Class 5 impact craters, 515 Class 6 impact craters, and 1,561 Class 7 impact craters.
[0078] Based on the morphological characteristics exhibited during the degradation process of impact craters, the impact crater ejecta, crater rim gap, crater rim sharpness, and crater rim damage degree P were selected. i Pit bottom filler, sand corrugation area ratio S i Coefficient of variation of pit bottom elevation V i Aspect Ratio T i Roughness of pit edge i and the abundance of superimposed impact craters N i Ten factors are used to describe degraded impact craters. Figure 1 Based on the ten descriptive factors selected above, the grading criteria for impact crater degradation were analyzed. According to the preservation status and morphological characteristics of each mapped impact crater, the degradation process of Martian impact craters was divided into seven degradation levels. These were named impact craters from level 1 to level 7, with level 1 being the freshest and level 7 being the most degraded.
[0079] The degradation levels from 1 to 4 are primarily determined by the condition of the crater's rim and the sand ripples on its bottom. Level 1 represents the ideal, pristine (freshest) state of the impact crater. A Level 1 impact crater is bowl-shaped or flat-bottomed cone-shaped, with a bottom filled with dark sand. S1 = 0, V1 can be as high as 60% or more, the ejecta shows sand ripples and well-preserved rock, and the crater's perimeter exhibits clear low-albedo radiation streaks. R1 = 1.07. A Level 1 impact crater has a complete, sharp, regularly rounded rim, no gaps, P1 = 0, no superimposed impact craters, N1 = 0, and a relatively high rim height, T1 = 0.93.
[0080] Class 2 impact craters are characterized by well-defined rims and a certain height (T2 = 0.070, average depth-to-diameter ratio 0.069). The rims are regular and continuous without gaps (P2 = 0, R2 = 1.21). The ejecta blanket contains continuous rock / non-rock material, although ejecta from craters with diameters of 30-60 meters may lack rock. Compared to Class 1 craters, Class 2 craters exhibit numerous, clearly defined sand ripples at the bottom, with a sub-meter to meter-scale structure and a dense distribution (S2 = 55.6%). Simultaneously, the undulating topography caused by the sand ripples results in the highest elevation variation coefficient (V2) fitting peak value for Class 2 craters (33.3%). Occasionally, one to two superimposed impact craters (N2) are found on the ejecta blanket, rim, and walls.
[0081] Due to continuous sediment accumulation caused by gravity erosion and wind transport, the bottom depth of the Class 3 impact craters has become shallower, with T3 = 0.60 and an average depth-to-diameter ratio of 0.55. However, high-reflectivity sand ripples still appear on the bottom, with a lower abundance than Class 2 craters, specifically S3 = 23.6% and V3 = 28.8%, and there are more superimposed impact craters than in Class 2 craters. Although the edges of Class 3 impact craters remain well-defined, their sharpness has decreased and some erosion gaps have appeared, with P3 less than 5% and R3 = 1.32. The number of superimposed impact craters (N3) has further increased by approximately 3 to 5.
[0082] The rims of Class 4 impact craters gradually degrade and decrease in height, exhibiting more gaps and notches compared to Class 3 craters (5% ≤ P4 < 15%), with R4 = 1.39. T4 = 0.046, and an average depth-to-diameter ratio of 0.047. Bright sand ripples are visible outside the crater rim, but only a few are present. The sand ripples disappear at the crater bottom, with S4 = 9.1% and V4 = 24.2%. From Class 2 to Class 4, the sand ripple structure gradually increases in size, while its abundance gradually decreases. Furthermore, smooth filling completely covers the bottom of the impact crater, making sand ripples difficult to observe. The density of superimposed impact craters further increases compared to Class 3, with N4 around 6.
[0083] The degradation levels of impact craters 5 to 7 are primarily determined by the morphology of the crater edges and the abundance of superimposed impact craters. Scale 5 craters exhibit significant erosion at the rim, with a further reduction in rim height compared to scale 4 (T5 = 0.037, average depth-to-diameter ratio 0.039), more fissures and gaps, and an increasingly incomplete rim shape. The degree of rim damage gradually increases, with 15% ≤ P5 < 25% and R5 = 1.21. Scale 5 craters are morphologically characterized by a depression with bright edges and a dark interior. The crater floor is primarily composed of smooth, sandy material (S5 = 0, V5 = 21.3%), and the infill retains clearly defined superimposed impact craters, indicating that the infill has hardened. Furthermore, the superimposed impact craters at the bottom of scale 5 craters are denser and more degraded, with up to eight N5 craters, and the rocks within the ejecta blanket are completely weathered and disappeared.
[0084] The rim of the Class 6 impact crater was almost completely destroyed (25% ≤ P6 < 50%), with R6 = 1.14, T6 = 0.031, and an average depth-to-diameter ratio of 0.029. The interior of the crater was very smooth, completely lacking the impact structure of ejecta, with S6 = 0 and V6 = 17.4%. Visually, it was interpreted as a sandy depression. A small amount of sand ripples remained on the exterior of the slightly raised rim remnants. Furthermore, the abundance of superimposed small impact craters was greater than that of Class 5, with approximately 8 to 10 N6 craters.
[0085] Level 7 craters are the most degraded impact craters in the study area, with their edges almost completely eroded. P7 is greater than 50%, T7 = 0.021, and the average depth-to-diameter ratio is 0.017. Visual interpretation reveals only a blurry, nearly circular structure, with R7 = 1.04. They are typically shallow depressions with flat bottoms. The V7 fitted peak center value is the lowest, at only 14.5%, and S7 = 0. If subsequent impact events are sufficiently intense, the shape of Level 7 craters may be further distorted into irregular shapes (e.g., sub-circular), with N7 values of 10 or more.
[0086] This embodiment classifies the degree of impact crater degradation solely based on morphological features, eliminating the need for extensive and complex calculations. Furthermore, it is unaffected by the irregularity of impact crater morphology or the heterogeneity of terrain, establishing a simple and efficient classification method. The classification method proposed in this embodiment is not limited by regional selection, exhibiting high universality and applicable to impact crater degradation classification work in other study areas of Mars.
[0087] Example 2
[0088] This embodiment discloses a degradation classification system for Martian impact craters that integrates morphology and erosion characteristics.
[0089] like Figure 4 As shown, the degradation classification system of Martian impact craters, which integrates morphology and erosion characteristics, includes:
[0090] The impact crater outline drawing module is configured to: acquire high-resolution remote sensing images of Mars, draw impact crater outlines using the three-point circle method, and identify impact craters in the study area.
[0091] The secondary impact crater exclusion module is configured to exclude secondary impact craters in the study area.
[0092] The descriptor selection module is configured to select ten descriptor factors to describe the impact craters in the study area: impact crater ejecta, crater rim gap, crater rim sharpness, crater rim damage degree, crater bottom filling material, sand ripple area ratio, crater bottom elevation variation coefficient, depth-to-diameter ratio, crater rim roughness, and abundance of superimposed impact craters.
[0093] The grading module is configured to analyze the grading criteria for impact crater degradation based on ten descriptive factors, and to divide the degradation process of Martian impact craters into seven degradation levels.
[0094] Example 3
[0095] The purpose of this embodiment is to provide a computer-readable storage medium.
[0096] A computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the steps in the method for classifying the degradation of Martian impact craters based on integrated morphology and erosion characteristics as described in Embodiment 1 of this disclosure.
[0097] Example 4
[0098] The purpose of this embodiment is to provide an electronic device.
[0099] An electronic device includes a memory, a processor, and a program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps in the method for classifying the degradation of Martian impact craters based on integrated morphology and erosion features as described in Embodiment 1 of this disclosure.
[0100] The steps and methods involved in the apparatuses of Embodiments 2, 3, and 4 above correspond to those in Embodiment 1. For specific implementation details, please refer to the relevant description section of Embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood as including any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and enabling the processor to perform any of the methods in this invention.
[0101] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.
[0102] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.
Claims
1. A method of crater degradation classification on Mars that integrates topography and erosion features, characterized in that, The method comprises the following steps: Obtaining a high-resolution remote sensing image of Mars, drawing a crater outline using a three-point circle drawing method, and identifying craters in the study area; Excluding secondary impact craters in the study area; Selecting ten description factors, i.e., ejecta, rim gap, rim sharpness, rim damage degree, crater bottom filling, sand ripple area ratio, crater bottom elevation variation coefficient, depth-diameter ratio, rim roughness, and superimposed impact crater number abundance, to describe the craters in the study area, specifically: The ejecta is the material excavated from the surface of Mars during the impact event and accumulated outside the crater rim. The rim gap is the gap and notch of the crater rim after the impact event. crater rim sharpness A i is a description of the sharpness of the impact crater rim, which is divided into four levels: the first level is the sharpest and most pointed, the second level is relatively sharp and clear, the third level is smooth, and the fourth level is that the crater rim is completely destroyed and very smooth; Crater rim breakage P i The length of the crater rim break is the percentage of the crater rim perimeter, divided into five intervals: the first interval is 0 to 5%, the second interval is 5% to 15%, the third interval is 15% to 25%, the fourth interval is 25% to 50%, and the fifth interval is 50% and above; The crater bottom filling is the material ejected to the crater bottom during the formation of the impact crater or subsequently moved to the crater bottom under the action of Martian wind and erosion. sand ripple area ratio S i The percentage of sand ripple area hitting the crater bottom to the total area of the crater bottom is divided into four intervals: the first interval is 0 to 20%, the second interval is 20% to 40%, the third interval is 40% to 60%, and the fourth interval is 60% and above. Coefficient of variation of pit floor elevation V i The ratio of the standard deviation of pit floor elevation to the average pit floor elevation is divided into three intervals: the first interval is 10% to 20%, the second interval is 20% to 40%, and the third interval is 30% to 60%. depth-to-diameter ratio T i is the ratio of the maximum height difference between the top of the crater rim and the crater floor to the diameter of the crater. Roughness of kerb R i The ratio of the actual circumference of the kerb to the ideal circular circumference of the kerb, divided into four intervals: the first interval is 0.9 to 1.1, the second interval is 1.1 to 1.3, the third interval is 1.2 to 1.4, and the fourth interval is 1.3 to 1.5; Superimposed crater abundance N i The superimposed crater abundance is divided into four intervals: the first interval is 0 to 3, the second interval is 3 to 8, the third interval is 5 to 10, and the fourth interval is 8 and above. Based on the ten description factors, the degradation level classification standard of the impact craters is analyzed, the degradation process of the impact craters on Mars is divided into seven degradation levels, and the seven degradation levels are named as 1-7 level impact craters, respectively, wherein the 1 level is the freshest impact crater, and the 7 level impact crater has the highest degradation degree.
2. The method for integrated crater shape and erosion feature degradation classification of Mars impact craters of claim 1, wherein, The three-point circle drawing method is to select three edge peak points of the impact crater to draw the crater outline.
3. The method for integrated crater shape and erosion feature degradation classification of Mars impact craters of claim 2, wherein, If the edge of the impact crater in the study area lacks obvious peak or is difficult to detect through the high-resolution image, the slope inflection point between the impact crater edge and the surrounding area is used to define the impact crater boundary based on the digital elevation model data.
4. The method for integrated crater shape and erosion feature degradation classification of Mars impact craters of claim 1, wherein, The judgment method of the secondary impact crater is: The ratio of depth to diameter of impact craters in the study area t <=0.07 and ellipticity e >=1.2 are considered to be secondary impact craters.
5. The method for grading the degradation of impact craters on Mars by integrating topography and erosion characteristics according to claim 1, characterized in that: Class 1 impact crater with distinct ejecta, complete, sharp, regular crater rim, no crater gap, dark sand fill in the bottom, S 1 belongs to the first interval, V 1 belongs to the third interval, R 1 belongs to the first interval, class 1 impact crater A 1 belongs to the first class, P 1 = 0, N 1 = 0, T 1 = 0.1; The 2nd grade impact crater has obvious splashes, regular and continuous crater rim without gaps, crater bottom terrain undulates, 0.07≤ T 2 < 0.09, A 2 belongs to the second grade, P 2 belongs to the first interval, and R 2 is the second interval, S 2 belongs to the fourth interval, V 2 is the third interval, N 2 is in the first interval; 3 Crater with well-defined rim, but reduced sharpness and some erosion notches, and with high albedo ripples on the floor, 0.05 ≤ T 3 < 0.08, S 3 is the second interval, V 3 is within the second interval, A 3 is the third interval, P 3 is the first interval, R 3 is the third interval, N 3 belongs to the second interval; 4 Gradual degradation of the crater rim with more cracks and gaps compared to level 3, partial disappearance of the sand ripples on the crater floor, smooth fill completely covering the crater floor, 0.04≤ T 4 < 0.06, A 4 is the third interval, P 4 is the second interval, R 4 is the fourth interval, S 4 is the first interval, V 4 belongs to the first interval, N 4 is the second interval; 5 Impact crater ejecta blanket rock is completely weathered away, crater rim is significantly eroded, more gaps and notches in the crater rim, crater rim shape starts to be incomplete, crater floor fill is mainly composed of smooth sandy material, 0.03≤ T 5 < 0.05, A 5 is the third level, P 5 belongs to the third interval, R 5 is the third interval, S 5 is the first interval, V 5 is the first interval, N 5 is the third interval; Class 6 impact craters are completely missing the impact structure of ejecta, the rim is almost completely destroyed, the interior is very smooth, and there are still a few sand waves outside the slightly raised rim remnants, A 6 is the fourth class, P 6 is the fourth interval, R 6 is the second interval, 0.02≤ T 6<0.04, S 6=0, V 5 is the first interval, N 6 belongs to the fourth interval; The rim of the 7-class impact crater has been eroded away, the floor is flat, and the terrain lacks significant relief as the degree of degradation deepens, A 7 is a fourth order, P 7 is a fifth interval, 0.01≤ T 7 < 0.03, R 7 is a first interval, V 7 is a first interval, S 7 = 0, N 7 is a fourth interval.
6. A Mars impact crater degradation classification system that integrates topography and erosion characteristics, characterized by: It comprises: The impact crater outline drawing module is configured to obtain a high-resolution remote sensing image of Mars, draw a crater outline using a three-point circle drawing method, and identify craters in the study area. The secondary impact crater exclusion module is configured to exclude secondary impact craters in the study area. The description factor selection module is configured to select ten description factors, i.e., ejecta, rim gap, rim sharpness, rim damage degree, crater bottom filling, sand ripple area ratio, crater bottom elevation variation coefficient, depth-diameter ratio, rim roughness, and superimposed impact crater number abundance, to describe the craters in the study area, specifically: The ejecta is the material excavated from the surface of Mars during the impact event and accumulated outside the crater rim. The rim gap is the gap and notch of the crater rim after the impact event. crater rim sharpness A i is a description of the sharpness of the impact crater rim, which is divided into four levels: the first level is the sharpest and most pointed, the second level is relatively sharp and well-defined, the third level is smooth, and the fourth level is that the crater rim is completely destroyed and very smooth; crater rim breakage P i The length of the crater rim break is the percentage of the crater rim perimeter, divided into five intervals: the first interval is 0 to 5%, the second interval is 5% to 15%, the third interval is 15% to 25%, the fourth interval is 25% to 50%, and the fifth interval is 50% and above; The crater bottom filling is the material ejected to the crater bottom during the formation of the impact crater or subsequently moved to the crater bottom under the action of Martian wind and erosion. sand ripple area ratio S i The percentage of sand ripple area hitting the crater bottom to the total area of the crater bottom is divided into four intervals: the first interval is 0 to 20%, the second interval is 20% to 40%, the third interval is 40% to 60%, and the fourth interval is 60% and above. Coefficient of variation of pit floor elevation V i The ratio of the standard deviation of pit floor elevation to the average pit floor elevation is divided into three intervals: the first interval is 10% to 20%, the second interval is 20% to 40%, and the third interval is 30% to 60%. depth-to-diameter ratio T i is the ratio of the maximum height difference between the top of the crater rim and the crater floor to the diameter of the crater. Roughness of kerb R i The ratio of the actual circumference of the kerb to the ideal circular circumference of the kerb, divided into four intervals: the first interval is 0.9 to 1.1, the second interval is 1.1 to 1.3, the third interval is 1.2 to 1.4, and the fourth interval is 1.3 to 1.5; Superimposed crater abundance N i The superimposed crater abundance is divided into four intervals: the first interval is 0 to 3, the second interval is 3 to 8, the third interval is 5 to 10, and the fourth interval is 8 and above. The grading module is configured to analyze the degradation level classification standard of the impact craters based on the ten description factors, divide the degradation process of the impact craters on Mars into seven degradation levels, and name the seven degradation levels as 1-7 level impact craters, respectively, wherein the 1 level is the freshest impact crater, and the 7 level impact crater has the highest degradation degree.
7. A computer-readable storage medium having stored thereon a program, characterized in that The program is executed by the processor to implement the steps in the method for grading the degradation of impact craters on Mars by integrating topography and erosion characteristics according to any one of claims 1-5.
8. An electronic device comprising a memory, a processor, and a program stored in the memory and capable of running on the processor, characterized by The processor executes the program to implement the steps in the method for grading the degradation of impact craters on Mars by integrating topography and erosion characteristics according to any one of claims 1-5.