A three-dimensional digital river channel simulation method based on remote sensing inversion calculation

Abstract

The present invention relates to the field of river channel simulation technology, and discloses a three-dimensional digital river channel simulation method based on remote sensing inversion calculation. River channel images are obtained through optical remote sensing technology, cloud cover is judged and eliminated, the river bank line is extracted, and then the river channel center line and the river channel width are obtained, and finally the three-dimensional digital simulation of the river channel is realized. The specific steps include: obtaining the initial remote sensing image of the target river channel, judging whether there is cloud cover and removing it, extracting and recording the endpoints and lengths of both banks of the river channel, dividing the river bank segmentation points proportionally, connecting the segmentation points on both banks to obtain the center line points and fitting them into the river channel center line. Subsequently, through the center line segmentation points, vertical lines are planned using the water flow direction to obtain the river channel width, and finally the digital simulation of the river channel is completed through the measuring scale calibration strategy. This method can effectively improve the accuracy of river channel simulation and provide a scientific basis for water conservancy management, environmental monitoring, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of river channel simulation, and particularly to a three-dimensional digital river channel simulation method based on remote sensing inversion calculation. Background Art

[0002] With the intensification of global climate change and human activities, the management and monitoring of river systems have become important tasks in the fields of environmental science and water conservancy engineering; digital river channel modeling is an important research topic in the fields of water conservancy, hydrology, and environmental monitoring; with the rapid development of remote sensing technology, using remote sensing data for three-dimensional digital modeling of river channels, especially a river channel simulation method based on remote sensing image inversion calculation, has become a research hotspot; however, there are still certain technical bottlenecks in existing remote sensing image processing technologies. When faced with complex river channel morphologies, existing technologies are unable to accurately calculate the midline of the river channel based on the lengths of the two banks of the river channel. The midline of the river channel is an important basis for measuring the width of the river channel. Incorrect calculation of the river channel midline will lead to incorrect calculation of the river channel width. In addition, when calculating the river channel width based on the flow direction of the river on the river channel midline, there are often situations where the river channel widths at different points intersect, resulting in inaccurate measurement problems.

[0003] In summary, there is an urgent need for a three-dimensional digital river channel simulation method based on remote sensing inversion calculation to accurately measure the width of the river channel and perform accurate river channel simulation. Summary of the Invention

[0004] The present invention provides a three-dimensional digital river channel simulation method based on remote sensing inversion calculation, which promotes the solution of the problems mentioned in the above background art.

[0005] The present invention provides the following technical solution: A three-dimensional digital river channel simulation method based on remote sensing inversion calculation, specifically including:

[0006] Obtain the river channel to be digitally simulated and denote it as the target river channel;

[0007] Obtain the optical remote sensing image of the target river channel through optical remote sensing technology and denote it as the initial remote sensing image;

[0008] Judge whether the target river channel in the initial remote sensing image is blocked by clouds;

[0009] If the target river channel in the initial remote sensing image is blocked by clouds, use the cloud and shadow removal algorithm to eliminate the clouds blocking the target river channel in the initial remote sensing image;

[0010] Denote the initial remote sensing image processed by the cloud and shadow removal algorithm or the initial remote sensing image in which the target river channel in the image is not blocked by clouds as the target remote sensing image;

[0011] Obtain the two banks of the target river channel in the target remote sensing image, and denote them as the first bank and the second bank respectively;

[0012] Denote the two endpoints of the first bank as the first endpoint and the second endpoint;

[0013] Denote the two endpoints of the second bank as the third endpoint and the fourth endpoint;

[0014] Specify the direction from the first endpoint to the second endpoint on the first bank as the positive direction of the first bank;

[0015] Specify the direction from the third endpoint to the fourth endpoint on the second bank as the positive direction of the second bank;

[0016] Obtain the length of the first bank, and denote it as the first length;

[0017] Obtain the length of the second bank, and denote it as the second length;

[0018] Obtain the center line of the target river channel according to the river channel center line acquisition strategy;

[0019] Denote the center line of the target river channel as the river channel center line;

[0020] Obtain the width of the target river channel according to the river channel width acquisition strategy;

[0021] Calibrate the data measured by the measuring ruler according to the measuring ruler calibration strategy;

[0022] Perform digital simulation on the river channel with the calibrated data.

[0023] Optionally, the obtaining the center line of the target river channel according to the river channel center line acquisition strategy specifically includes:

[0024] Calculate the first length ÷ the second length, and denote the result as the river bank length ratio;

[0025] Obtain the endpoints of the second bank, where the endpoint closest to the first endpoint is the third endpoint, and the endpoint closest to the second endpoint is the fourth endpoint;

[0026] On the second bank, starting from the third endpoint, take segmentation points in sequence in the positive direction of the second bank, with an interval of 10 meters between each segmentation point, and sequentially denote the segmentation points as the first segmentation point of the second bank, the second segmentation point of the second bank... the A-th segmentation point of the second bank along the positive direction of the second bank, where A refers to the number of segmentation points on the second bank;

[0027] On the first bank, starting from the first endpoint, take dividing points in sequence in the positive direction of the first bank, with the interval between each dividing point being 10 meters × the bank length ratio, and sequentially mark the dividing points as the first dividing point of the first bank, the second dividing point of the first bank... the Bth dividing point of the first bank along the positive direction of the first bank, where B refers to the number of dividing points on the first bank, and B = A.

[0028] Optionally, obtaining the midline of the target river channel according to the midline acquisition strategy of the river channel specifically includes:

[0029] Connect the first dividing point of the first bank and the first dividing point of the second bank to form a first auxiliary line segment, and obtain the midpoint of the first auxiliary line segment, denoted as the first midline point; connect the second dividing point of the first bank and the second dividing point of the second bank to form a second auxiliary line segment, and obtain the midpoint of the second auxiliary line segment, denoted as the second midline point... connect the Bth dividing point of the first bank and the Ath dividing point of the second bank to form the Cth auxiliary line segment, and obtain the midpoint of the Ath auxiliary line segment, denoted as the Cth midline point, and C = B = A;

[0030] Obtain the first midline point, the second midline point... the Cth midline point;

[0031] Fit the first midline point, the second midline point... the Cth midline point into a smooth curve;

[0032] The smooth curve is the midline of the target river channel.

[0033] Optionally, obtaining the width of the target river channel according to the river channel width acquisition strategy specifically includes:

[0034] Obtain the midline of the river channel, and denote the two endpoints of the midline of the river channel as the first point position and the second point position respectively;

[0035] Where the first point position is the endpoint among the two endpoints of the midline of the river channel that is closest to the first endpoint and the third endpoint;

[0036] The second point position is the endpoint among the two endpoints of the midline of the river channel that is closest to the second endpoint and the fourth endpoint;

[0037] Specify the direction from the first point position to the second point position on the midline of the river channel and the positive direction of the midline of the river channel;

[0038] On the midline of the river channel, starting from the first point position, take dividing points in sequence in the positive direction of the midline of the river channel, with the interval between each dividing point being 30 meters, and sequentially mark the dividing points as the first midline dividing point, the second midline dividing point... the Dth midline dividing point along the positive direction of the midline of the river channel, where D refers to the number of midline dividing points.

[0039] Optionally, obtaining the width of the target river channel according to the river channel width acquisition strategy specifically includes:

[0040] Obtain the water flow direction at the first midline division point, denoted as the first water flow direction;

[0041] Draw a straight line parallel to the horizontal plane and perpendicular to the first water flow direction through the first midline division point, denoted as the first straight line;

[0042] The intersection point of the first straight line and the first riverbank is denoted as the first measurement point on the first riverbank, and the intersection point of the first straight line and the second riverbank is denoted as the first measurement point on the second riverbank;

[0043] Obtain the water flow direction at the second midline division point, denoted as the second water flow direction;

[0044] Draw a straight line parallel to the horizontal plane and perpendicular to the second water flow direction through the second midline division point, denoted as the second straight line;

[0045] The intersection point of the second straight line and the first riverbank is denoted as the second intersection point on the first riverbank, and the intersection point of the second straight line and the second riverbank is denoted as the second intersection point on the second riverbank;

[0046] Connect the first measurement point on the first riverbank and the first measurement point on the second riverbank to form a straight line, denoted as the first connection line;

[0047] Connect the second intersection point on the first riverbank and the second intersection point on the second riverbank to form a straight line, denoted as the second connection line;

[0048] If the first connection line and the second connection line do not intersect, then denote the second intersection point on the first riverbank as the second measurement point on the first riverbank, and denote the second intersection point on the second riverbank as the second measurement point on the second riverbank;

[0049] Optionally, obtaining the width of the target river channel according to the river channel width acquisition strategy specifically includes:

[0050] If the first connection line and the second connection line intersect, obtain the measurement points according to the measurement point acquisition strategy when intersecting;

[0051] Then draw a straight line parallel to the first connection line and parallel to the horizontal plane through the second midline division point, denoted as the third connection line;

[0052] Draw a straight line parallel to the first connection line, the third connection line and the horizontal plane and equidistant from the first connection line and the third connection line between the first connection line and the third connection line through the river channel midline, denoted as the fourth connection line;

[0053] Obtain the distance between the third connection line and the fourth connection line, denoted as the auxiliary distance;

[0054] Draw a straight line parallel to the third connection line and the horizontal plane and at a distance of the auxiliary distance from the third connection line on the other side of the third connection line through the river channel midline, denoted as the fifth connection line;

[0055] Obtain the river channel area between the fourth connection line and the fifth connection line, denoted as the auxiliary area;

[0056] Perform grid division processing on the auxiliary area;

[0057] The shape of the grid is a square with a side length of 1 meter;

[0058] Obtain the water flow direction of the geometric center of each grid;

[0059] Rotate the second connection line with the second center splitting point as the rotation axis. When the second connection line has no intersection with both the fourth connection line and the fifth connection line;

[0060] Obtain all the grids passed by the second connection line;

[0061] For each grid passed by the second connection line;

[0062] Obtain the angle of the smaller of the two angles formed by the water flow direction of the grid geometric center and the second connection line, denoted as the auxiliary angle;

[0063] Calculate 90 degrees - the auxiliary angle, and denote the result as the intersection angle;

[0064] Calculate the average value of the intersection angles of all grids;

[0065] When the average value is the smallest, denote the intersection point of the second connection line and the first river bank as the second measurement point of the first river bank, and denote the intersection point of the second connection line and the second river bank as the second measurement point of the second river bank.

[0066] Optionally, obtaining the width of the target river channel according to the river channel width acquisition strategy specifically includes:

[0067] Obtain the water flow direction at the third midline splitting point, denoted as the fourth water flow direction;

[0068] Draw a straight line parallel to the horizontal plane and perpendicular to the fourth water flow direction through the third midline splitting point, denoted as the third straight line;

[0069] Denote the intersection point of the third straight line and the first river bank as the third intersection point of the first river bank, and denote the intersection point of the third straight line and the second river bank as the third intersection point of the second river bank;

[0070] Connect the second measurement point of the first river bank and the second measurement point of the second river bank to form a straight line, denoted as the sixth connection line;

[0071] Connect the third intersection point of the first river bank and the third intersection point of the second river bank to form a straight line, denoted as the seventh connection line;

[0072] If the sixth connection line and the seventh connection line do not intersect, then denote the third intersection point of the first river bank as the third measurement point of the first river bank, and denote the third intersection point of the second river bank as the third measurement point of the second river bank;

[0073] If the sixth connection line and the seventh connection line intersect; obtain the third measuring point on the first river bank and the third measuring point on the second river bank corresponding to the third midline dividing point according to the measuring point acquisition strategy when intersecting;

[0074] In the above way, obtain the fourth measuring point on the first river bank and the fourth measuring point on the second river bank corresponding to the fourth midline dividing point, the fifth measuring point on the first river bank and the fifth measuring point on the second river bank corresponding to the fifth midline dividing point... the Dth measuring point on the first river bank and the Dth measuring point on the second river bank corresponding to the Dth midline dividing point in sequence.

[0075] Optionally, obtaining the width of the target river channel according to the river channel width acquisition strategy specifically includes:

[0076] Use a measuring ruler to obtain the reading of the measuring ruler between the first measuring point on the first river bank and the first measuring point on the second river bank, specifically:

[0077] Place the starting point of the measuring ruler at a position one meter directly above the first measuring point on the first river bank, pull the measuring ruler to make the straight line formed by the measuring ruler between the first measuring point on the first river bank and the first measuring point on the second river bank parallel to the horizontal plane, and record the reading of the measuring ruler at a position one meter above the first measuring point on the second river bank, denoted as the first reading;

[0078] In the above way, obtain the second reading between the second measuring point on the first river bank and the second measuring point on the second river bank, the third reading between the third measuring point on the first river bank and the third measuring point on the second river bank... the Dth reading between the Dth measuring point on the first river bank and the Dth measuring point on the second river bank in sequence.

[0079] Optionally, correcting the data measured by the measuring ruler according to the measuring ruler calibration strategy specifically includes:

[0080] Set up two movable vertical rods on the horizontal ground, and the upper ends of the vertical rods are used to clamp the measuring ruler;

[0081] When the reading of the measuring ruler between the two vertical rods is the first reading, obtain the distance between the two vertical rods on the ground, denoted as the first distance, and the first distance is the actual distance between the first measuring point on the first river bank and the first measuring point on the second river bank. When the reading of the measuring ruler between the two vertical rods is the second reading, obtain the distance between the two vertical rods on the ground, denoted as the second distance, and the second distance is the actual distance between the second measuring point on the first river bank and the second measuring point on the second river bank... When the reading of the measuring ruler between the two vertical rods is the Dth reading, obtain the distance between the two vertical rods on the ground, denoted as the Dth distance, and the Dth distance is the actual distance between the Dth measuring point on the first river bank and the Dth measuring point on the second river bank.

[0082] The present invention has the following beneficial effects:

[0083] 1. This three-dimensional digital river channel simulation method based on remote sensing inversion calculation can effectively eliminate the influence of clouds and shadows and retain the real information of the river channel by using the cloud and shadow removal algorithm to process the initial remote sensing image. The advantage of this process is that by ensuring the clear visibility of the target river channel, the three-dimensional digital reconstruction of the river channel by the model is more accurate, avoiding incorrect analysis caused by cloud or shadow interference. This improves the quality of the image and makes subsequent data extraction and simulation more reliable.

[0084] 2. This three-dimensional digital river channel simulation method based on remote sensing inversion calculation can accurately extract the target river channel from the image and clearly define the two banks of the river channel, facilitating subsequent digital river channel modeling. The advantage of this method is that it improves the accuracy of digital modeling through clear division criteria. Further, by using the real river channel features in the remote sensing image for modeling, it can not only capture the river channel contour more accurately but also reduce human errors, which is particularly important in the remote sensing monitoring of large-scale river channels.

[0085] 3. This three-dimensional digital river channel simulation method based on remote sensing inversion calculation can make the river channel simulation more conform to the actual terrain changes by calculating the length ratio of the two banks and adjusting the spacing of the segmentation points based on this ratio. This strategy helps to cope with the different widths and morphological changes on both sides of the river channel and ensures more refined modeling of each area. Specifically, this processing method solves the differences in the bank morphology of different regions by adaptively adjusting the spacing of the segmentation points, making the model more conform to the actual terrain. At the same time, by connecting each pair of bank segmentation points and finding their midpoints, and then fitting these midpoints with a smooth curve, an accurate river channel centerline can be constructed. This approach effectively avoids the possible artificial intervention errors in traditional methods and smooths the irregularities caused by remote sensing image errors through curve fitting, thus obtaining a more accurate river channel centerline. This can not only effectively reflect the actual morphology of the river channel but also provide more accurate path data for subsequent three-dimensional modeling.

[0086] 4. For the three-dimensional digital river channel simulation method based on remote sensing inversion calculation, in the first step of the river channel width acquisition strategy, first determine the two endpoints of the river channel center line, namely the "first point position" and the "second point position"; the selection of these two endpoints is based on the distance relationship with the endpoints on both banks of the river channel; then, obtain multiple center line segmentation points at certain intervals between the two endpoints of the river channel center line; at each center line segmentation point, determine the corresponding water flow direction, and perpendicularly make a straight line at each segmentation point through this direction; the intersection points of this straight line with the two banks of the river channel are the actual measurement points of the river channel; this step ensures that the measurement is consistent with the actual water flow direction, thus avoiding measurement errors caused by different water flow directions; the water flow direction has an important impact on the river channel morphology and width changes, so through the measurement line perpendicular to the water flow direction, the width of the river channel can be more realistically reflected, especially in the case where the water flow direction is curved or non-linear; at each center line segmentation point, determine the width by the intersection of the straight line perpendicular to the water flow direction with the river bank; this straight line will intersect with the two river banks respectively, and the intersection points are the actual river bank measurement points; then, measure the distance between these intersection points to obtain the corresponding river channel width data; for multiple measurement points, connect the corresponding intersection points to form a connection line, and further check whether these connection lines intersect. If there is no intersection point, it means that the river channel width measurement points determined by the water flow direction through the center line segmentation points are correct, and there is no need to find other measurement points; if there are intersection points, it means that the river channel width measurement points determined by the water flow direction through the center line segmentation points are wrong, and other measurement points need to be found; during the process of finding other measurement points; with the segmentation point as the center, delimit a grid area, and rotate the second connection line with the second center segmentation point as the rotation axis. When the second connection line has no intersection points with the fourth connection line and the fifth connection line; obtain the angle of the smaller of the two included angles formed by the water flow direction of the geometric centers of all the grids passed by the second connection line and the second connection line, and record it as the auxiliary angle; calculate 90 degrees - the auxiliary angle, and record it as the intersection angle, and calculate the average value of all the intersection angles. The smallest average value represents that the water flow directions in all the grids under the second connection line are basically the same; select the intersection points of the second connection line corresponding to the smallest average value and the two river banks as the measurement points, which can ensure that the selected measurement points can truly reflect the width of the river channel and have strong representativeness, and can play a key role in the simulation.

[0087] 5. The three-dimensional digital river channel simulation method based on remote sensing inversion calculation can calibrate the measuring ruler by setting up a movable vertical rod, and the true distance of each measuring point can be obtained; when using the measuring ruler to measure the distance, the measuring ruler may sag due to the long distance, resulting in the reading of the measuring ruler not being the true distance; the advantage of this strategy is that it can eliminate the systematic error that the measuring tool may bring, making the final measurement result closer to the actual situation. Through multi-point calibration, the accuracy of remote sensing data in terrain modeling can be effectively improved. Especially in wide river channels or complex terrains, the measurement error may be larger, so this calibration method is particularly important. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Figure 1 It is a schematic diagram showing that the first connection line and the second connection line of the present invention do not intersect.

[0089] Figure 2 It is a schematic diagram showing that the first connection line and the second connection line of the present invention intersect. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0090] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0091] Embodiment, refer to Figure 1 - Figure 2 , a three-dimensional digital river channel simulation method based on remote sensing inversion calculation, specifically including:

[0092] Obtain the river channel to be simulated digitally and record it as the target river channel;

[0093] Obtain the optical remote sensing image of the target river channel through optical remote sensing technology and record it as the initial remote sensing image;

[0094] Judge whether the target river channel in the initial remote sensing image is blocked by clouds;

[0095] If the target river channel in the initial remote sensing image is blocked by clouds, use the cloud and shadow removal algorithm to remove the clouds blocking the target river channel in the initial remote sensing image;

[0096] Record the initial remote sensing image processed by the cloud and shadow removal algorithm or the initial remote sensing image in which the target river channel in the image is not blocked by clouds as the target remote sensing image;

[0097] The three-dimensional digital river channel simulation method based on remote sensing inversion calculation can effectively eliminate the influence of clouds and shadows by using the cloud and shadow removal algorithm to process the initial remote sensing image, and retain the real information of the river channel. The advantage of this process is that by ensuring the clear visibility of the target river channel, the three-dimensional digital reconstruction of the river channel by the model is more accurate, avoiding incorrect analysis caused by cloud or shadow interference. This improves the quality of the image, making subsequent data extraction and simulation more reliable.

[0098] Obtain the two river banks of the target river channel in the target remote sensing image, and denote them as the first river bank and the second river bank respectively.

[0099] Denote the two endpoints of the first river bank as the first endpoint and the second endpoint.

[0100] Denote the two endpoints of the second river bank as the third endpoint and the fourth endpoint.

[0101] Specify the direction from the first endpoint to the second endpoint on the first river bank as the positive direction of the first river bank.

[0102] Specify the direction from the third endpoint to the fourth endpoint on the second river bank as the positive direction of the second river bank.

[0103] Obtain the length of the first river bank, denoted as the first length.

[0104] Obtain the length of the second river bank, denoted as the second length.

[0105] The three-dimensional digital river channel simulation method based on remote sensing inversion calculation accurately extracts the target river channel from the image and clearly defines the two river banks of the river channel, facilitating subsequent digital river channel modeling. The advantage of this method is that by clear division criteria, the accuracy of digital modeling is improved. Further using the real river channel features in the remote sensing image for modeling can not only capture the river channel contour more accurately, but also reduce human errors, which is particularly important in the remote sensing monitoring of large-area river channels.

[0106] Obtain the midline of the target river channel according to the river channel midline acquisition strategy.

[0107] Denote the midline of the target river channel as the river channel midline.

[0108] Obtain the width of the target river channel according to the river channel width acquisition strategy.

[0109] Calibrate the data measured by the measuring ruler according to the measuring ruler calibration strategy.

[0110] Conduct digital simulation of the river channel with the calibrated data.

[0111] The obtaining of the midline of the target river channel according to the river channel midline acquisition strategy specifically includes:

[0112] Calculate the first length divided by the second length, and record the result as the riverbank length ratio;

[0113] Obtain the endpoints of the second riverbank. Among them, the endpoint closest to the first endpoint is the third endpoint, and the endpoint closest to the second endpoint is the fourth endpoint;

[0114] On the second riverbank, starting from the third endpoint, take segmentation points in sequence in the positive direction of the second riverbank. The interval between each segmentation point is 10 meters, and sequentially record the segmentation points as the first segmentation point of the second riverbank, the second segmentation point of the second riverbank... the A-th segmentation point of the second riverbank along the positive direction of the second riverbank, where A refers to the number of segmentation points on the second riverbank;

[0115] On the first riverbank, starting from the first endpoint, take segmentation points in sequence in the positive direction of the first riverbank. The interval between each segmentation point is 10 meters × the riverbank length ratio, and sequentially record the segmentation points as the first segmentation point of the first riverbank, the second segmentation point of the first riverbank... the B-th segmentation point of the first riverbank along the positive direction of the first riverbank, where B refers to the number of segmentation points on the first riverbank, and B = A.

[0116] Obtain the center line of the target river according to the center line acquisition strategy of the river course, specifically including:

[0117] Connect the first segmentation point of the first riverbank and the first segmentation point of the second riverbank to form the first auxiliary line segment, and obtain the midpoint of the first auxiliary line segment, denoted as the first center line point; connect the second segmentation point of the first riverbank and the second segmentation point of the second riverbank to form the second auxiliary line segment, and obtain the midpoint of the second auxiliary line segment, denoted as the second center line point... connect the B-th segmentation point of the first riverbank and the A-th segmentation point of the second riverbank to form the C-th auxiliary line segment, and obtain the midpoint of the A-th auxiliary line segment, denoted as the C-th center line point, and C = B = A;

[0118] Obtain the first center line point, the second center line point... the C-th center line point;

[0119] Fit the first center line point, the second center line point... the C-th center line point into a smooth curve;

[0120] The smooth curve is the center line of the target river course;

[0121] The three-dimensional digital river channel simulation method based on remote sensing inversion calculation can make the river channel simulation more conform to the actual terrain changes by calculating the length ratio of the two riverbanks and adjusting the spacing of the segmentation points based on this ratio. This strategy helps to cope with the different widths and morphological changes on both sides of the river channel, ensuring more refined modeling of each area. Specifically, this processing method solves the differences in the riverbank morphology in different regions by adaptively adjusting the spacing of the segmentation points, making the model more conform to the actual terrain; at the same time, by connecting each pair of riverbank segmentation points and finding their midpoints, and then fitting these midpoints with a smooth curve, an accurate river channel centerline can be constructed; this approach effectively avoids the possible artificial intervention errors in the traditional method, and by means of curve fitting, smooths the irregularities caused by remote sensing image errors, thus obtaining a more accurate river channel centerline. This can not only effectively reflect the actual morphology of the river channel, but also provide more accurate path data for subsequent three-dimensional modeling.

[0122] The obtaining of the width of the target river channel according to the river channel width obtaining strategy specifically includes:

[0123] Obtain the river channel centerline, and the two endpoints of the river channel centerline are respectively denoted as the first point position and the second point position;

[0124] Among them, the first point position is the endpoint of the two endpoints of the river channel centerline that is closest to the first endpoint and the third endpoint;

[0125] The second point position is the endpoint of the two endpoints of the river channel centerline that is closest to the second endpoint and the fourth endpoint;

[0126] Specify the direction from the first point position to the second point position on the river channel centerline and the positive direction of the river channel centerline;

[0127] On the river channel centerline, starting from the first point position, take segmentation points in turn in the positive direction of the river channel centerline, and the interval between each segmentation point is 30 meters, and sequentially denote the segmentation points as the first centerline segmentation point, the second centerline segmentation point... the Dth centerline segmentation point along the positive direction of the river channel centerline, where D refers to the number of centerline segmentation points.

[0128] The obtaining of the width of the target river channel according to the river channel width obtaining strategy specifically includes:

[0129] Obtain the water flow direction at the first centerline segmentation point, denoted as the first water flow direction;

[0130] Draw a straight line parallel to the horizontal plane and perpendicular to the first water flow direction through the first centerline segmentation point, denoted as the first straight line;

[0131] The intersection point of the first straight line and the first riverbank is denoted as the first measurement point of the first riverbank, and the intersection point of the first straight line and the second riverbank is denoted as the first measurement point of the second riverbank;

[0132] Obtain the water flow direction at the second midline division point, denoted as the second water flow direction;

[0133] Draw a straight line passing through the second midline division point, parallel to the horizontal plane and perpendicular to the second water flow direction, denoted as the second straight line;

[0134] The intersection point of the second straight line and the first riverbank is denoted as the second intersection point of the first riverbank, and the intersection point of the second straight line and the second riverbank is denoted as the second intersection point of the second riverbank;

[0135] Connect the first measurement point on the first riverbank and the first measurement point on the second riverbank to form a straight line, denoted as the first connection line;

[0136] Connect the second intersection point of the first riverbank and the second intersection point of the second riverbank to form a straight line, denoted as the second connection line;

[0137] Refer to Figure 1 , if the first connection line and the second connection line do not intersect, then denote the second intersection point of the first riverbank as the second measurement point of the first riverbank, and denote the second intersection point of the second riverbank as the second measurement point of the second riverbank;

[0138] The method for obtaining the width of the target river channel according to the river channel width obtaining strategy specifically includes:

[0139] Refer to Figure 2 , if the first connection line and the second connection line intersect, obtain the measurement points according to the measurement point obtaining strategy when intersecting;

[0140] Then draw a straight line passing through the second midline division point, parallel to the first connection line and parallel to the horizontal plane, denoted as the third connection line;

[0141] Draw a straight line between the first connection line and the third connection line, parallel to the first connection line, the third connection line and the horizontal plane, and at an equal distance from the first connection line and the third connection line, denoted as the fourth connection line;

[0142] Obtain the distance between the third connection line and the fourth connection line, denoted as the auxiliary distance;

[0143] Draw a straight line on the other side of the third connection line, parallel to the third connection line and the horizontal plane, and at a distance of the auxiliary distance from the third connection line, denoted as the fifth connection line;

[0144] Obtain the river channel area between the fourth connection line and the fifth connection line, denoted as the auxiliary area;

[0145] Perform grid division processing on the auxiliary area;

[0146] The shape of the grid is a square with a side length of 1 meter;

[0147] Obtain the water flow direction of the geometric center of each grid;

[0148] Rotate the second connecting line with the second central division point as the rotation axis. When there are no intersections between the second connecting line and the fourth and fifth connecting lines;

[0149] Obtain all the grids passed by the second connecting line;

[0150] For each grid passed by the second connecting line;

[0151] Obtain the angle of the smaller of the two angles formed by the water flow direction at the geometric center of the grid and the second connecting line, and record it as the auxiliary angle;

[0152] Calculate 90 degrees - the auxiliary angle, and record the result as the intersection angle;

[0153] Calculate the average value of the intersection angles of all grids;

[0154] When the average value is the smallest, mark the intersection point of the second connecting line and the first river bank as the second measurement point on the first river bank, and mark the intersection point of the second connecting line and the second river bank as the second measurement point on the second river bank.

[0155] The obtaining of the width of the target river channel according to the river channel width obtaining strategy specifically includes:

[0156] Obtain the water flow direction at the third midline division point, and record it as the fourth water flow direction;

[0157] Draw a straight line parallel to the horizontal plane and perpendicular to the fourth water flow direction through the third midline division point, and record it as the third straight line;

[0158] Mark the intersection point of the third straight line and the first river bank as the third intersection point on the first river bank, and mark the intersection point of the third straight line and the second river bank as the third intersection point on the second river bank;

[0159] Connect the second measurement point on the first river bank and the second measurement point on the second river bank to form a straight line, and record it as the sixth connecting line;

[0160] Connect the third intersection point on the first river bank and the third intersection point on the second river bank to form a straight line, and record it as the seventh connecting line;

[0161] If the sixth connecting line and the seventh connecting line do not intersect, mark the third intersection point on the first river bank as the third measurement point on the first river bank, and mark the third intersection point on the second river bank as the third measurement point on the second river bank;

[0162] If the sixth connecting line and the seventh connecting line intersect; obtain the third measurement point on the first river bank and the third measurement point on the second river bank corresponding to the third midline division point according to the measurement point obtaining strategy at the time of intersection;

[0163] In the above manner, successively obtain the fourth measuring point on the first bank corresponding to the fourth midline division point and the fourth measuring point on the second bank, the fifth measuring point on the first bank corresponding to the fifth midline division point and the fifth measuring point on the second bank... the Dth measuring point on the first bank corresponding to the Dth midline division point and the Dth measuring point on the second bank;

[0164] For the three-dimensional digital river channel simulation method based on remote sensing inversion calculation, in the first step of the river channel width acquisition strategy, first determine the two endpoints of the river channel midline, namely the "first point" and the "second point"; the selection of these two endpoints is based on the distance relationship with the endpoints on both banks of the river channel; then, obtain multiple midline division points at certain intervals between the two endpoints of the river channel midline; at each midline division point, determine the corresponding water flow direction, and perpendicularly make a straight line at each division point through this direction; the intersection points of this straight line with both banks of the river channel are the actual measuring points of the river channel; this step ensures that the measurement is consistent with the actual water flow direction, thereby avoiding measurement errors caused by different water flow directions; the water flow direction has an important impact on the river channel morphology and width change, so through the measurement line perpendicular to the water flow direction, the width of the river channel can be more truly reflected, especially in the case where the water flow direction is curved or non-linear; at each midline division point, determine the width by the intersection of the straight line perpendicular to the water flow direction with the river bank; this straight line will intersect with both river banks respectively, and the intersection points are the actual river bank measuring points; then, measure the distance between these intersection points to obtain the corresponding river channel width data; for multiple measuring points, connect the corresponding intersection points to form a connection line, and further check whether these connection lines intersect. If there is no intersection point, it means that the river channel width measuring points determined by the water flow direction through the midline division point are correct, and there is no need to find other measuring points; if there is an intersection point, it means that the river channel width measuring points determined by the water flow direction through the midline division point are wrong, and other measuring points need to be found; in the process of finding other measuring points; with the division point as the center, delimit a grid area, and rotate the second connection line with the second central division point as the rotation axis. When the second connection line has no intersection point with both the fourth connection line and the fifth connection line; obtain the angle of the smaller of the two angles formed by the water flow direction of the geometric centers of all the grids passed by the second connection line and the second connection line, and record it as the auxiliary angle; calculate 90 degrees - the auxiliary angle, and record it as the intersection angle, and calculate the average value of all the intersection angles. The smallest average value represents that the water flow directions in all the grids under the second connection line are basically the same; select the intersection points of the second connection line corresponding to the smallest average value and both river banks as the measuring points, which can ensure that the selected measuring points can truly reflect the width of the river channel and have strong representativeness, and can play a key role in the simulation.

[0165] The obtaining of the width of the target river channel according to the river channel width acquisition strategy specifically includes:

[0166] Obtain the measuring tape reading between the first measuring point on the first riverbank and the first measuring point on the second riverbank using a measuring tape, specifically as follows:

[0167] Place the starting point of the measuring tape at a position one meter directly above the first measuring point on the first riverbank. Pull the measuring tape to make the straight line formed by the measuring tape between the first measuring point on the first riverbank and the first measuring point on the second riverbank parallel to the horizontal plane, and record the reading of the measuring tape at a position one meter above the first measuring point on the second riverbank, denoted as the first reading;

[0168] In the above manner, sequentially obtain the second reading between the second measuring point on the first riverbank and the second measuring point on the second riverbank, the third reading between the third measuring point on the first riverbank and the third measuring point on the second riverbank... the Dth reading between the Dth measuring point on the first riverbank and the Dth measuring point on the second riverbank.

[0169] Calibrate the data measured by the measuring tape according to the measuring tape calibration strategy, specifically including:

[0170] Set up two movable vertical poles on the horizontal ground, and the upper ends of the vertical poles are used to clamp the measuring tape;

[0171] When the reading of the measuring tape between the two vertical poles is the first reading, obtain the distance between the two vertical poles on the ground, denoted as the first distance, and the first distance is the actual distance between the first measuring point on the first riverbank and the first measuring point on the second riverbank. When the reading of the measuring tape between the two vertical poles is the second reading, obtain the distance between the two vertical poles on the ground, denoted as the second distance, and the second distance is the actual distance between the second measuring point on the first riverbank and the second measuring point on the second riverbank... When the reading of the measuring tape between the two vertical poles is the Dth reading, obtain the distance between the two vertical poles on the ground, denoted as the Dth distance, and the Dth distance is the actual distance between the Dth measuring point on the first riverbank and the Dth measuring point on the second riverbank;

[0172] This three-dimensional digital river channel simulation method based on remote sensing inversion calculation can obtain the actual distance of each measuring point by setting up movable vertical poles for measuring tape calibration. When using a measuring tape to measure distance, the measuring tape may sag due to the long distance, resulting in the reading of the measuring tape not being the actual distance. The advantage of this strategy is that it can eliminate the systematic error that may be brought by the measuring tool, making the final measurement result closer to the actual situation. Through multi-point calibration, the accuracy of remote sensing data in terrain modeling can be effectively improved. Especially in wide river channels or complex terrains, the measurement error may be larger, so this calibration method is particularly important.

[0173] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device.

[0174] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A three-dimensional digital river channel simulation method based on remote sensing inversion calculation, characterized in that, Specifically include: Obtain the river channel to be simulated numerically and denote it as the target river channel; Obtain the optical remote sensing image of the target river channel through optical remote sensing technology and denote it as the initial remote sensing image; Judge whether the target river channel in the initial remote sensing image is blocked by clouds; If the target river channel in the initial remote sensing image is blocked by clouds, use the cloud and shadow removal algorithm to eliminate the clouds blocking the target river channel in the initial remote sensing image; Denote the initial remote sensing image processed by the cloud and shadow removal algorithm or the initial remote sensing image in which the target river channel is not blocked by clouds as the target remote sensing image; Obtain the two riverbanks of the target river channel in the target remote sensing image and denote them as the first riverbank and the second riverbank respectively; Denote the two endpoints of the first riverbank as the first endpoint and the second endpoint; Denote the two endpoints of the second riverbank as the third endpoint and the fourth endpoint; Specify the direction from the first endpoint to the second endpoint on the first riverbank as the positive direction of the first riverbank; Specify the direction from the third endpoint to the fourth endpoint on the second riverbank as the positive direction of the second riverbank; Obtain the length of the first riverbank and denote it as the first length; Obtain the length of the second riverbank and denote it as the second length; Obtain the center line of the target river channel according to the center line acquisition strategy of the river channel. Specifically: Calculate the first length ÷ the second length, and denote the result as the riverbank length ratio; Obtain the endpoints of the second riverbank, where the endpoint closest to the first endpoint is the third endpoint, and the endpoint closest to the second endpoint is the fourth endpoint; On the second riverbank, starting from the third endpoint, take segmentation points in sequence in the positive direction of the second riverbank, with an interval of 10 meters between each segmentation point, and sequentially denote the segmentation points as the first segmentation point of the second riverbank, the second segmentation point of the second riverbank... the A-th segmentation point of the second riverbank along the positive direction of the second riverbank, where A refers to the number of segmentation points on the second riverbank; On the first riverbank, starting from the first endpoint, take segmentation points in sequence in the positive direction of the first riverbank, with an interval of 10 meters × the riverbank length ratio between each segmentation point, and sequentially denote the segmentation points as the first segmentation point of the first riverbank, the second segmentation point of the first riverbank... the B-th segmentation point of the first riverbank along the positive direction of the first riverbank, where B refers to the number of segmentation points on the first riverbank, and B = A; Connect the first segmentation point of the first riverbank and the first segmentation point of the second riverbank to form the first auxiliary line segment, and obtain the midpoint of the first auxiliary line segment and denote it as the first center line point; connect the second segmentation point of the first riverbank and the second segmentation point of the second riverbank to form the second auxiliary line segment, and obtain the midpoint of the second auxiliary line segment and denote it as the second center line point... connect the B-th segmentation point of the first riverbank and the A-th segmentation point of the second riverbank to form the C-th auxiliary line segment, and obtain the midpoint of the A-th auxiliary line segment and denote it as the C-th center line point, and C = B = A; Obtain the first center line point, the second center line point... the C-th center line point; Fit the first center line point, the second center line point... the C-th center line point into a smooth curve; The smooth curve is the center line of the target river channel; Denote the center line of the target river channel as the river channel center line; Obtain the width of the target river channel according to the river channel width acquisition strategy. Specifically: Obtain the river channel center line, and denote the two endpoints of the river channel center line as the first point position and the second point position respectively; Wherein the first point is the endpoint among the two endpoints of the river channel center line that is closest to the first endpoint and the third endpoint; The second point is the endpoint among the two endpoints of the river channel center line that is closest to the second endpoint and the fourth endpoint; Define the direction from the first point to the second point on the river channel center line and the positive direction of the river channel center line; On the river channel center line, starting from the first point, take segmentation points in sequence in the positive direction of the river channel center line, with an interval of 30 meters between each segmentation point, and sequentially mark the segmentation points as the first center line segmentation point, the second center line segmentation point... the Dth center line segmentation point along the positive direction of the river channel center line, where D refers to the number of center line segmentation points; Obtain the water flow direction at the first center line segmentation point and denote it as the first water flow direction; Draw a straight line parallel to the horizontal plane and perpendicular to the first water flow direction through the first center line segmentation point, and denote it as the first straight line; The intersection point of the first straight line and the first river bank is denoted as the first measurement point on the first river bank, and the intersection point of the first straight line and the second river bank is denoted as the first measurement point on the second river bank; Obtain the water flow direction at the second center line segmentation point and denote it as the second water flow direction; Draw a straight line parallel to the horizontal plane and perpendicular to the second water flow direction through the second center line segmentation point, and denote it as the second straight line; The intersection point of the second straight line and the first river bank is denoted as the second intersection point on the first river bank, and the intersection point of the second straight line and the second river bank is denoted as the second intersection point on the second river bank; Connect the first measurement point on the first river bank and the first measurement point on the second river bank to form a straight line, and denote it as the first connection line; Connect the second intersection point on the first river bank and the second intersection point on the second river bank to form a straight line, and denote it as the second connection line; If the first connection line and the second connection line do not intersect, then denote the second intersection point on the first river bank as the second measurement point on the first river bank, and denote the second intersection point on the second river bank as the second measurement point on the second river bank; If the first connection line and the second connection line intersect, obtain the measurement points according to the measurement point acquisition strategy at the time of intersection; Then draw a straight line parallel to the first connection line and parallel to the horizontal plane through the second center line segmentation point, and denote it as the third connection line; Draw a straight line parallel to the first connection line, the third connection line and the horizontal plane and equidistant from the first connection line and the third connection line through the river channel center line between the first connection line and the third connection line, and denote it as the fourth connection line; Obtain the distance between the third connection line and the fourth connection line, and denote it as the auxiliary distance; Draw a straight line parallel to the third connection line and the horizontal plane and with a distance of the auxiliary distance from the third connection line through the river channel center line on the other side of the third connection line, and denote it as the fifth connection line; Obtain the river channel area between the fourth connection line and the fifth connection line, and denote it as the auxiliary area; Perform grid division processing on the auxiliary area; The shape of the grid is a square with a side length of 1 meter; Obtain the water flow direction at the geometric center of each grid; Rotate the second connection line around the second center segmentation point as the rotation axis, and when the second connection line has no intersection with both the fourth connection line and the fifth connection line; Obtain all the grids passed by the second connection line; For each grid passed by the second connection line; Obtain the angle of the smaller angle formed by the water flow direction at the geometric center of the grid and the second connection line, and denote it as the auxiliary angle; Calculate 90 degrees - the auxiliary angle, and denote the result as the intersection angle; Calculate the average value of the intersection angles of all the grids; When the average value is the smallest, mark the intersection point of the second connection line and the first river bank as the second measurement point on the first river bank, and mark the intersection point of the second connection line and the second river bank as the second measurement point on the second river bank; Obtain the water flow direction at the third midline dividing point, denoted as the fourth water flow direction; Draw a straight line parallel to the horizontal plane and perpendicular to the fourth water flow direction through the third midline dividing point, denoted as the third straight line; Mark the intersection point of the third straight line and the first river bank as the third intersection point on the first river bank, and mark the intersection point of the third straight line and the second river bank as the third intersection point on the second river bank; Connect the second measurement point on the first river bank and the second measurement point on the second river bank to form a straight line, denoted as the sixth connection line; Connect the third intersection point on the first river bank and the third intersection point on the second river bank to form a straight line, denoted as the seventh connection line; If the sixth connection line and the seventh connection line do not intersect, mark the third intersection point on the first river bank as the third measurement point on the first river bank, and mark the third intersection point on the second river bank as the third measurement point on the second river bank; If the sixth connection line and the seventh connection line intersect; obtain the third measurement point on the first river bank and the third measurement point on the second river bank corresponding to the third midline dividing point according to the measurement point acquisition strategy when intersecting; In the above way, sequentially obtain the fourth measurement point on the first river bank and the fourth measurement point on the second river bank corresponding to the fourth midline dividing point, the fifth measurement point on the first river bank and the fifth measurement point on the second river bank corresponding to the fifth midline dividing point... the Dth measurement point on the first river bank and the Dth measurement point on the second river bank corresponding to the Dth midline dividing point; Use a measuring ruler to obtain the reading of the measuring ruler between the first measurement point on the first river bank and the first measurement point on the second river bank, specifically: Place the starting point of the measuring ruler at a position one meter directly above the first measurement point on the first river bank, pull the measuring ruler so that the straight line formed by the measuring ruler between the first measurement point on the first river bank and the first measurement point on the second river bank is parallel to the horizontal plane, and record the reading of the measuring ruler at a position one meter above the first measurement point on the second river bank, denoted as the first reading; In the above way, sequentially obtain the second reading between the second measurement point on the first river bank and the second measurement point on the second river bank, the third reading between the third measurement point on the first river bank and the third measurement point on the second river bank... the Dth reading between the Dth measurement point on the first river bank and the Dth measurement point on the second river bank; Calibrate the data measured by the measuring ruler according to the measuring ruler calibration strategy, specifically: Set two movable vertical rods on the horizontal ground, and the upper ends of the vertical rods are used to clamp the measuring ruler; When the reading of the measuring ruler between the two vertical rods is the first reading, obtain the distance between the two vertical rods on the ground, denoted as the first distance, and the first distance is the actual distance between the first measurement point on the first river bank and the first measurement point on the second river bank. When the reading of the measuring ruler between the two vertical rods is the second reading, obtain the distance between the two vertical rods on the ground, denoted as the second distance, and the second distance is the actual distance between the second measurement point on the first river bank and the second measurement point on the second river bank... When the reading of the measuring ruler between the two vertical rods is the Dth reading, obtain the distance between the two vertical rods on the ground, denoted as the Dth distance, and the Dth distance is the actual distance between the Dth measurement point on the first river bank and the Dth measurement point on the second river bank; Conduct digital simulation on the river channel based on the calibrated data.

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