CN108051811B - Method and device for analyzing mesoscale vortex - Google Patents
Method and device for analyzing mesoscale vortex Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
- G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
- G01S13/9021—SAR image post-processing techniques
- G01S13/9029—SAR image post-processing techniques specially adapted for moving target detection within a single SAR image or within multiple SAR images taken at the same time
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
- G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
- G01S13/9021—SAR image post-processing techniques
- G01S13/9027—Pattern recognition for feature extraction
Abstract
The application discloses a method and a device for analyzing mesoscale vortexes, wherein the method comprises the following steps: acquiring a synthetic aperture radar image to be processed containing at least one mesoscale vortex to be analyzed; determining a plurality of pixel points forming at least one mesoscale vortex edge to be analyzed from a synthetic aperture radar image to be processed; forming an initial pixel point group by pixels with continuous pixel point coordinates to obtain a plurality of initial pixel point groups; determining the longitude distance and the latitude distance of each initial pixel point group according to the longitude and latitude of the head pixel point and the tail pixel point in each initial pixel point group; determining that the longitude distance is greater than the longitude distance average value, and the initial pixel point group with the latitude distance greater than the latitude distance average value is a target pixel point group; and fitting the pixels in the target pixel group to obtain the center and the radius of the fitting circle. Through the embodiment of the application, the accuracy of the determined center and radius of the mesoscale vortex is improved.
Description
Technical Field
The application relates to a satellite remote sensing ocean monitoring technology, in particular to a method and a device for analyzing mesoscale vortexes.
Background
With the development of science and technology, the relationship between human beings and the sea is more and more close, and the human beings operate a ship and an underwater aircraft on the sea surface, and the ship and the underwater aircraft are influenced by the distribution of the flow velocity of the sea in the aspects of navigation safety and use efficiency. In the ocean, mesoscale vortexes exist, the mesoscale vortexes rotate and move forwards in the ocean, and in the moving process of the mesoscale vortexes, the delivered momentum and energy directly influence the flow velocity distribution of the ocean environment.
In practical applications, in order to reduce the influence on the safety and the use efficiency of the sea surface ship and the underwater line warship caused by the change of the ocean flow velocity caused by the mesoscale vortex, the detection of the center and the radius of the mesoscale vortex in the ocean is of great significance.
In the prior art, the accuracy of the center and the radius of the mesoscale vortex is low by processing the synthetic aperture radar image containing the mesoscale vortex.
Disclosure of Invention
Based on the above, the application provides an analysis method of the mesoscale vortex, which is used for improving the accuracy of the center and the radius of the mesoscale vortex determined from the synthetic aperture radar image.
The application also provides an analysis device of the mesoscale vortex, which is used for ensuring the realization and the application of the method in practice.
The technical scheme provided by the application is as follows:
the application discloses a method for analyzing mesoscale vortexes, which comprises the following steps:
acquiring a synthetic aperture radar image to be processed; the synthetic aperture radar image to be processed comprises at least one mesoscale vortex to be analyzed;
determining a plurality of pixel points forming the at least one mesoscale vortex edge to be analyzed from the synthetic aperture radar image to be processed;
analyzing the coordinates of a plurality of pixel points forming the edge of the at least one mesoscale vortex to be analyzed, and forming initial pixel point groups by the pixel points with continuous coordinates to obtain a plurality of initial pixel point groups;
determining the longitude distance and the latitude distance of each initial pixel point group according to the longitude and latitude of the head pixel point and the tail pixel point in each initial pixel point group;
determining that the longitude distance is greater than the longitude distance average value, and the initial pixel point group with the latitude distance greater than the latitude distance average value is a target pixel point group; the longitude distance average is: an average value of longitude distances of the initial pixel point group; the latitude distance average value is: an average value of the latitude distances of the initial pixel point group;
and fitting the pixels in the target pixel group to obtain the center and the radius of the fitting circle.
Wherein, the determining a plurality of pixel points forming the at least one mesoscale vortex edge to be analyzed from the synthetic aperture radar image to be processed comprises:
determining a plurality of first pixel points of a representation coastline belonging to a preset longitude and latitude coordinate range according to the longitude and latitude coordinates corresponding to each pixel point in the synthetic aperture radar image to be processed;
determining pixel points outside the area formed by the first pixel points in the synthetic aperture radar image to be processed as pixel points to be processed;
determining the gradient amplitude of each pixel point to be processed;
and determining a plurality of to-be-processed pixel points of which the gradient amplitudes belong to a preset gradient range as a plurality of pixel points representing the edge of the at least one to-be-analyzed mesoscale vortex.
Wherein, the analysis constitutes a plurality of pixel point coordinates of the at least one mesoscale vortex edge to be analyzed, and constitutes the pixel points with continuous coordinates into an initial pixel point group, so as to obtain a plurality of initial pixel point groups, including:
according to a preset sequence, sequentially determining a plurality of pixel points forming the edge of the at least one mesoscale vortex to be analyzed as target pixel points to be processed; the preset sequence comprises: according to the sequence of continuous rows or continuous columns in the synthetic aperture radar image to be processed, and aiming at each row or each column, according to the sequence of continuous pixel point coordinates;
aiming at any target pixel point to be processed with the coordinate (i, j), executing according to the following process:
determining four pixel points of which the coordinates corresponding to the target pixel point to be processed are (i, j-1), (i-1, j) and (i-1, j +1) in sequence;
if no marked target pixel point exists in the four pixel points corresponding to the target pixel point to be processed, the marking value corresponding to the target pixel point to be processed is as follows: adding 1 to the current maximum mark value;
if at least one marked target pixel point exists in the four pixel points corresponding to the target pixel point to be processed, determining the minimum marking value in the marking values corresponding to the marked target pixel point as the marking value of the target pixel point to be processed;
updating the non-minimum mark value in the marked target pixel point to be the minimum mark value in the four pixel points corresponding to the target pixel point to be processed;
and determining a plurality of target pixel points with the same mark value as an initial pixel point group according to the mark value corresponding to each target pixel point to be processed to obtain a plurality of initial pixel point groups.
Wherein, the pixel in the fitting target pixel group obtains the circle center and the radius of the fitting circle, and comprises:
determining second pixel points with the maximum value and the minimum value of coordinates in the horizontal direction and the vertical direction respectively according to the coordinates of a plurality of pixel points contained in each target pixel point group to obtain four second pixel points;
and determining the circle center and the radius of a fitting circle closest to the coordinates of the four second pixel points according to the coordinates of the four second pixel points.
Wherein the method further comprises:
determining the center and the radius of each fitting circle as the center and the radius of a mesoscale vortex;
marking a center of each mesoscale vortex in the synthetic aperture radar image to be processed.
The application also discloses an analytical equipment of mesoscale vortex, the device includes:
the acquisition unit is used for acquiring a synthetic aperture radar image to be processed; the synthetic aperture radar image to be processed comprises at least one mesoscale vortex to be analyzed;
a first determining unit, configured to determine, from the to-be-processed synthetic aperture radar image, a plurality of pixel points that constitute the at least one to-be-analyzed mesoscale vortex edge;
the analysis unit is used for analyzing the coordinates of a plurality of pixel points forming the edge of the at least one mesoscale vortex to be analyzed, and forming initial pixel point groups by the pixel points with continuous coordinates to obtain a plurality of initial pixel point groups;
the second determining unit is used for determining the longitude distance and the latitude distance of each initial pixel point group according to the longitude and latitude of the head pixel point and the tail pixel point in each initial pixel point group;
the third determining unit is used for determining that the longitude distance is greater than the average longitude distance, and the initial pixel group with the latitude distance greater than the average latitude distance is a target pixel group; the longitude distance average is: an average value of longitude distances of the initial pixel point group; the latitude distance average value is: an average value of the latitude distances of the initial pixel point group;
and the fitting unit is used for fitting the pixels in the target pixel group to obtain the center and the radius of the fitting circle.
Wherein the first determination unit includes:
the first determining subunit is used for determining a plurality of first pixel points of a representation coastline belonging to a preset longitude and latitude coordinate range according to the longitude and latitude coordinates corresponding to each pixel point in the synthetic aperture radar image to be processed;
a second determining subunit, configured to determine, as a pixel to be processed, a pixel outside an area formed by the plurality of first pixels in the synthetic aperture radar image to be processed;
the third determining subunit is used for determining the gradient amplitude of each pixel point to be processed;
and the fourth determining subunit is used for determining a plurality of to-be-processed pixel points of which the gradient amplitudes belong to a preset gradient range as a plurality of pixel points representing the at least one to-be-analyzed mesoscale vortex edge.
Wherein the analysis unit comprises:
a fifth determining subunit, configured to sequentially determine, according to a preset sequence, a plurality of pixel points that constitute the at least one mesoscale vortex edge to be analyzed as target pixel points to be processed; the preset sequence comprises: according to the sequence of continuous rows or continuous columns in the synthetic aperture radar image to be processed, and aiming at each row or each column, according to the sequence of continuous pixel point coordinates;
the execution subunit is configured to execute, according to the following procedure, any target pixel point to be processed with the coordinate (i, j):
determining four pixel points of which the coordinates corresponding to the target pixel point to be processed are (i, j-1), (i-1, j) and (i-1, j +1) in sequence;
if no marked target pixel point exists in the four pixel points corresponding to the target pixel point to be processed, the marking value corresponding to the target pixel point to be processed is as follows: adding 1 to the current maximum mark value;
if at least one marked target pixel point exists in the four pixel points corresponding to the target pixel point to be processed, determining the minimum marking value in the marking values corresponding to the marked target pixel point as the marking value of the target pixel point to be processed;
updating the non-minimum mark value in the marked target pixel point to be the minimum mark value in the four pixel points corresponding to the target pixel point to be processed;
and determining a plurality of target pixel points with the same mark value as an initial pixel point group according to the mark value corresponding to each target pixel point to be processed to obtain a plurality of initial pixel point groups.
Wherein the fitting unit comprises:
a sixth determining subunit, configured to determine, for each target pixel point group, a second pixel point whose coordinate is the maximum value and the minimum value in the horizontal direction and the vertical direction, respectively, according to the coordinates of the plurality of pixel points included in the target pixel point group, and obtain four second pixel points;
and the seventh determining subunit is configured to determine, according to the coordinates of the four second pixel points, a circle center and a radius of a fitting circle closest to the coordinates of the four second pixel points.
Wherein the apparatus further comprises:
the fourth determining unit is used for determining the circle center and the radius of each fitting circle as the center and the radius of a mesoscale vortex;
a marking unit for marking a center of each mesoscale vortex in the synthetic aperture radar image to be processed.
The beneficial effect of this application does:
in the embodiment of the application, a plurality of initial pixel point groups which possibly form a continuous part of the edge of at least one mesoscale vortex to be analyzed are obtained from a synthetic aperture radar image to be processed containing the at least one mesoscale vortex to be analyzed; in the embodiment of the present application, the latitude distance average value and the longitude distance average value of all the initial pixel point groups are obtained according to the latitude distance and the longitude distance of each initial pixel point group; and taking the latitude distance average value and the longitude distance average value as reference values for judging whether an initial pixel group is a continuous part of the edge of a mesoscale vortex, so that in at least one target pixel group of which the latitude distance is greater than the latitude distance average value and the longitude distance is greater than the longitude distance average value in a plurality of initial pixel groups, the probability that each target pixel group is a continuous part in the edge of the mesoscale vortex is increased, and therefore, the accuracy of the determined center and radius of the mesoscale vortex is improved in the embodiment of the application.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a flow chart of an embodiment of a method for analyzing mesoscale vortices in the present application;
fig. 2 is a schematic structural diagram of an embodiment of an analysis apparatus for mesoscale vortices in the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 1, a flow diagram of an embodiment of a method of analyzing mesoscale vortices in the present application is shown, which may include the steps of:
step 101: and receiving a synthetic aperture radar image to be processed.
In this embodiment, a part of the ocean including the mesoscale vortexes is photographed by the high-resolution three-dimensional synthetic aperture radar, so as to obtain a high-resolution three-dimensional synthetic aperture radar image. In this step, a synthetic aperture radar image to be processed is received, wherein the synthetic aperture radar image to be processed indicates that there is a synthetic aperture radar image of a mesoscale vortex to be analyzed.
Step 102: and preprocessing the synthetic aperture radar image to be processed to obtain a preprocessed image.
After receiving the synthetic aperture radar image to be processed, then, in this step, preprocessing the synthetic aperture radar image to be processed, wherein the preprocessing the synthetic aperture radar image includes: and carrying out image compression, continental rejection and radiation correction on the synthetic aperture radar image to be processed. The image compression is a process of processing pixel values of a plurality of pixel points in an image and synthesizing the pixel values into a pixel point pixel value so as to reduce the calculation amount; the continental rejection is to mark pixel points representing continental characters in the synthetic aperture radar image to be processed so as to operate the pixel points outside the characteristic continental characters in the subsequent process; the radiation correction is: replacing pixel values of pixel points in the received synthetic aperture radar image to be processed with: and characterizing the backscattering coefficient corresponding to the pixel point. For convenience of description, in this embodiment, an image obtained by preprocessing a synthetic aperture radar image to be processed is referred to as a preprocessed image, and pixels other than pixels marked as characterizing continents in the preprocessed image are collectively referred to as pixels to be processed. At this time, the pixel value corresponding to each preprocessed pixel point in the preprocessed image represents the backscattering coefficient of the real object corresponding to the pixel point.
Step 103: and determining a plurality of pixel points forming at least one mesoscale vortex edge to be analyzed from the synthetic aperture radar image to be processed.
After preprocessing the synthetic aperture radar image, then, in this step, determining pixel points of which the gradient values corresponding to the pixel values are greater than the preset gradient values from the pixel points to be processed. Specifically, the process of determining a plurality of pixel points forming at least one mesoscale vortex edge to be analyzed from the preprocessed pixel points may include steps a1 to a step a 5:
step A1: and determining a plurality of first pixel points of the characterization coastline which belong to a preset latitude and longitude coordinate range according to the latitude and longitude coordinates corresponding to each pixel point in the synthetic aperture radar image to be processed.
In the synthetic aperture radar image to be processed, the longitude and latitude of the four pixel points positioned at the most edge are known, so that the longitude and latitude of each pixel point in the synthetic aperture radar image to be processed can be obtained according to the coordinates of the pixel points with the known longitude and latitude in the synthetic aperture radar image to be processed. In practical application, the latitude and longitude range of the pixel points representing the shoreline in the ocean is known, so that the pixel points representing the shoreline are determined in the synthetic aperture radar image to be processed, the pixel points representing the shoreline form a closed area, and the pixel points inside the closed area are the pixel points representing continents. For convenience of description, in this embodiment, a pixel point representing a coastline in the synthetic aperture radar image to be processed is referred to as a first pixel point, and a plurality of first pixel points are obtained at this time.
Step A2: and determining pixel points outside the area formed by the first pixel points in the synthetic aperture radar image to be processed as pixel points to be processed.
After a plurality of first pixel points representing coastlines in the synthetic aperture radar image to be processed are obtained, in the step, pixel points outside a closed area formed by the plurality of first pixel points are determined as pixel points to be processed.
Step A3: and performing smooth filtering on the preprocessed image.
After the pixel points to be processed are obtained, in this step, smoothing filtering is performed on the preprocessed image, for example, smoothing filtering may be performed by using a gaussian function with a variance of 1.4.
Step A4: and determining the gradient amplitude and the gradient direction of each pixel point to be processed after smooth filtering.
After smooth filtering is performed on the preprocessed image, then, in this step, the gradient amplitude and the gradient direction of each pixel point to be processed after smooth filtering are determined.
Step A5: and determining a plurality of to-be-processed pixel points of which the gradient amplitudes belong to a preset gradient range as a plurality of pixel points representing at least one to-be-analyzed mesoscale vortex edge.
After the gradient amplitude of each pixel point to be processed is determined, in this step, a plurality of pixel points to be processed, of which the gradient amplitudes belong to a preset range, are determined as a plurality of pixel points representing at least one mesoscale vortex edge to be analyzed.
Step 104: and according to a preset sequence, sequentially determining a plurality of pixel points forming at least one mesoscale vortex edge to be analyzed as target pixel points to be processed.
After obtaining a plurality of pixel points that constitute at least one mesoscale vortex edge, then, in this step, according to the order of predetermineeing, determine a plurality of pixel points in proper order as pending target pixel point, wherein, predetermineeing the order and include: and according to the sequence of continuous rows or continuous columns in the synthetic aperture radar image to be processed, and aiming at each row or each column, according to the sequence of continuous pixel point coordinates. For example, the method includes that the preprocessed image includes … … a first pixel point in a first row and a first column, … … a second pixel point in a first row and a second column, 8932 a pixel point in a first column in a second row and a second column, … … a pixel point in a last row and a last column in a second row, … … a pixel point in a first row and a first column in a last row, and … … a pixel point in a last row and a last column in a last row and a second column.
Step 105: and (3) executing any target pixel point to be processed with the coordinate (i, j) according to a preset flow.
The preset process may include:
determining four pixel points of which the coordinates corresponding to the target pixel point to be processed are (i, j-1), (i-1, j) and (i-1, j +1) in sequence;
if no marked target pixel point exists in the four pixel points corresponding to the target pixel point to be processed, the marking value corresponding to the target pixel point to be processed is as follows: adding 1 to the current maximum mark value;
if at least one marked target pixel point exists in the four pixel points corresponding to the target pixel point to be processed, determining the minimum marking value in the marking values corresponding to the marked target pixel point as the marking value of the target pixel point to be processed;
updating the non-minimum mark value in the marked target pixel point to be the minimum mark value in four pixel points corresponding to the target pixel point to be processed;
and determining a plurality of target pixel points with the same mark value as an initial pixel point group according to the mark value corresponding to each target pixel point to be processed to obtain a plurality of initial pixel point groups.
The purpose of the above steps 104 to 105 is: analyzing the coordinates of a plurality of pixel points forming at least one mesoscale vortex edge to be analyzed, and forming initial pixel point groups by the pixel points with continuous coordinates to obtain a plurality of initial pixel point groups.
Step 106: and determining the longitude distance and the latitude distance of each initial pixel point group according to the longitude and latitude of the head pixel point and the tail pixel point in each initial pixel point group.
After obtaining a plurality of initial pixel point groups, then, in this step, for each initial pixel point group, determining longitude and latitude distances of the head and tail pixel points according to the longitude and latitude corresponding to the head and tail two pixel points in the initial pixel point group, and determining the longitude and latitude distances of the head and tail pixel points as the longitude and latitude distances of the initial pixel point group.
Step 107: determining that the longitude distance is greater than the longitude distance average value, and the initial pixel point group with the latitude distance greater than the latitude distance average value is a target pixel point group; the longitude distance average is: an average value of longitude distances of the initial pixel point group; the latitude distance average value is: and the average value of the latitude distances of the initial pixel point group.
After the longitude distance and the latitude distance of each initial pixel point group are obtained, in this step, an average value of the longitude distances and an average value of the latitude distances of the initial pixel point groups are determined, all the initial pixel point groups with the longitude distances larger than the average value of the longitude distances and the latitude distances larger than the average value of the latitude distances are determined as target pixel point groups, and at this time, at least one target pixel point group is obtained.
Step 108: and respectively carrying out least square circle fitting on the pixel points in each target pixel point group to obtain the center coordinates and the radius of a fitting circle corresponding to the pixel points in each target pixel point group.
After at least one target pixel point group is obtained, in the step, aiming at each target pixel point group, the least square method circle fitting is adopted for pixel points in the target pixel point group, and the circle center and the radius of a fitting circle corresponding to the target pixel point group are obtained.
Specifically, the process of determining the center and the radius of the fitting circle corresponding to each target pixel point group for the pixel points in each target pixel point group may include step B1 to step B2:
step B1: and aiming at each target pixel point group, determining second pixel points with the maximum value and the minimum value of the coordinates in the horizontal direction and the vertical direction respectively according to the coordinates of a plurality of pixel points contained in the target pixel point group, and obtaining four second pixel points.
And respectively determining pixel points with the minimum value and the maximum value respectively taken by coordinates in the horizontal direction and the vertical direction from the pixel points contained in each target pixel point group according to the position coordinates of the target pixel points in the preprocessed image in each target pixel point group, and obtaining four pixel points corresponding to the target group.
Step B2: and determining the circle center and the radius of a fitting circle closest to the coordinates of the four second pixel points according to the coordinates of the four pixel points.
After the four pixel points corresponding to the target pixel point group are obtained, in the step, the coordinates of the four pixel points are used, a least square method is adopted for fitting, a fitting circle closest to the coordinates of the four pixel points is fitted, and the center coordinates and the radius of the fitting circle are determined.
Step 109: and determining the circle center and the radius of each fitting circle as the center and the radius of a mesoscale vortex, and marking the center of each mesoscale vortex in the synthetic aperture radar image to be processed.
After the circle center coordinates of each fitting circle and the radius of each fitting circle are obtained, in the step, the circle center and the radius of each fitting circle are determined as the center and the radius of one mesoscale vortex, and the center of each mesoscale vortex is marked in the synthetic aperture radar image to be processed.
According to the method and the device, a plurality of initial pixel point groups which possibly form a continuous part of the edge of at least one mesoscale vortex to be analyzed are obtained from the synthetic aperture radar image to be processed containing the at least one mesoscale vortex to be analyzed; in the embodiment of the present application, the latitude distance average value and the longitude distance average value of all the initial pixel point groups are obtained according to the latitude distance and the longitude distance of each initial pixel point group; and taking the latitude distance average value and the longitude distance average value as reference values for judging whether an initial pixel group is a continuous part of the edge of a mesoscale vortex, so that in at least one target pixel group of which the latitude distance is greater than the latitude distance average value and the longitude distance is greater than the longitude distance average value in a plurality of initial pixel groups, the probability that each target pixel group is a continuous part in the edge of the mesoscale vortex is increased, and therefore, the accuracy of the determined center and radius of the mesoscale vortex is improved in the embodiment of the application.
Referring to fig. 2, a schematic structural diagram of an embodiment of an analysis apparatus for mesoscale vortices in the present application is shown, and the apparatus embodiment may include:
an obtaining unit 201, configured to obtain a synthetic aperture radar image to be processed; the synthetic aperture radar image to be processed comprises at least one mesoscale vortex to be analyzed;
a first determining unit 202, configured to determine, from the to-be-processed synthetic aperture radar image, a plurality of pixel points that form the at least one to-be-analyzed mesoscale vortex edge;
wherein, the first determining unit 202 may include:
the first determining subunit is used for determining a plurality of first pixel points of a representation coastline belonging to a preset longitude and latitude coordinate range according to the longitude and latitude coordinates corresponding to each pixel point in the synthetic aperture radar image to be processed;
a second determining subunit, configured to determine, as a pixel to be processed, a pixel outside an area formed by the plurality of first pixels in the synthetic aperture radar image to be processed;
the third determining subunit is used for determining the gradient amplitude of each pixel point to be processed;
and the fourth determining subunit is used for determining a plurality of to-be-processed pixel points of which the gradient amplitudes belong to a preset gradient range as a plurality of pixel points representing the at least one to-be-analyzed mesoscale vortex edge.
The analysis unit 203 is configured to analyze coordinates of a plurality of pixel points forming the at least one mesoscale vortex edge to be analyzed, and form pixel points with continuous coordinates into an initial pixel point group to obtain a plurality of initial pixel point groups;
among them, the analysis unit 203 may include:
a fifth determining subunit, configured to sequentially determine, according to a preset sequence, a plurality of pixel points that constitute the at least one mesoscale vortex edge to be analyzed as target pixel points to be processed; the preset sequence comprises: according to the sequence of continuous rows or continuous columns in the synthetic aperture radar image to be processed, and aiming at each row or each column, according to the sequence of continuous pixel point coordinates;
the execution subunit is configured to execute, according to the following procedure, any target pixel point to be processed with the coordinate (i, j):
determining four pixel points of which the coordinates corresponding to the target pixel point to be processed are (i, j-1), (i-1, j) and (i-1, j +1) in sequence;
if no marked target pixel point exists in the four pixel points corresponding to the target pixel point to be processed, the marking value corresponding to the target pixel point to be processed is as follows: adding 1 to the current maximum mark value;
if at least one marked target pixel point exists in the four pixel points corresponding to the target pixel point to be processed, determining the minimum marking value in the marking values corresponding to the marked target pixel point as the marking value of the target pixel point to be processed;
updating the non-minimum mark value in the marked target pixel point to be the minimum mark value in the four pixel points corresponding to the target pixel point to be processed;
and determining a plurality of target pixel points with the same mark value as an initial pixel point group according to the mark value corresponding to each target pixel point to be processed to obtain a plurality of initial pixel point groups.
A second determining unit 204, configured to determine a longitude distance and a latitude distance of each initial pixel group according to the longitude and latitude of the head and tail pixels in each initial pixel group;
a third determining unit 205, configured to determine that the longitude distance is greater than the average longitude distance, and the initial pixel group with the latitude distance greater than the average latitude distance is the target pixel group; the longitude distance average is: an average value of longitude distances of the initial pixel point group; the latitude distance average value is: an average value of the latitude distances of the initial pixel point group;
and the fitting unit 206 is configured to fit the pixels in the target pixel group to obtain a center and a radius of a fitting circle.
Wherein, the fitting unit 206 may include:
a sixth determining subunit, configured to determine, for each target pixel point group, a second pixel point whose coordinate is the maximum value and the minimum value in the horizontal direction and the vertical direction, respectively, according to the coordinates of the plurality of pixel points included in the target pixel point group, and obtain four second pixel points;
and the seventh determining subunit is configured to determine, according to the coordinates of the four second pixel points, a circle center and a radius of a fitting circle closest to the coordinates of the four second pixel points.
Wherein, the embodiment of the device can also comprise:
the fourth determining unit is used for determining the circle center and the radius of each fitting circle as the center and the radius of a mesoscale vortex;
a marking unit for marking a center of each mesoscale vortex in the synthetic aperture radar image to be processed.
The embodiments are described in a progressive manner in the specification, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. In this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprising," "including," and the like, as used herein, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is, the meaning of "includes but is not limited to". The invention can be applied to various fields, such as a mobile phone, a.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (8)
1. A method of analyzing mesoscale vortices, the method comprising:
acquiring a synthetic aperture radar image to be processed; the synthetic aperture radar image to be processed comprises at least one mesoscale vortex to be analyzed;
determining a plurality of pixel points forming the at least one mesoscale vortex edge to be analyzed from the synthetic aperture radar image to be processed;
analyzing the coordinates of a plurality of pixel points forming the edge of the at least one mesoscale vortex to be analyzed, and forming initial pixel point groups by the pixel points with continuous coordinates to obtain a plurality of initial pixel point groups;
determining the longitude distance and the latitude distance of each initial pixel point group according to the longitude and latitude of the head pixel point and the tail pixel point in each initial pixel point group;
determining that the longitude distance is greater than the longitude distance average value, and the initial pixel point group with the latitude distance greater than the latitude distance average value is a target pixel point group; the longitude distance average is: an average value of longitude distances of the initial pixel point group; the latitude distance average value is: an average value of the latitude distances of the initial pixel point group;
fitting the pixels in the target pixel group to obtain the center and the radius of a fitting circle; determining the center and the radius of each fitting circle as the center and the radius of a mesoscale vortex;
marking a center of each mesoscale vortex in the synthetic aperture radar image to be processed.
2. The method according to claim 1, wherein said determining a plurality of pixel points constituting said at least one mesoscale vortex edge to be analyzed from said synthetic aperture radar image to be processed comprises:
determining a plurality of first pixel points of a representation coastline belonging to a preset longitude and latitude coordinate range according to the longitude and latitude coordinates corresponding to each pixel point in the synthetic aperture radar image to be processed;
determining pixel points outside the area formed by the first pixel points in the synthetic aperture radar image to be processed as pixel points to be processed;
determining the gradient amplitude of each pixel point to be processed;
and determining a plurality of to-be-processed pixel points of which the gradient amplitudes belong to a preset gradient range as a plurality of pixel points representing the edge of the at least one to-be-analyzed mesoscale vortex.
3. The method of claim 1, wherein the analyzing coordinates of a plurality of pixels forming the at least one mesoscale vortex edge to be analyzed, and forming pixels with continuous coordinates into an initial pixel group to obtain a plurality of initial pixel groups comprises:
according to a preset sequence, sequentially determining a plurality of pixel points forming the edge of the at least one mesoscale vortex to be analyzed as target pixel points to be processed; the preset sequence comprises: according to the sequence of continuous rows or continuous columns in the synthetic aperture radar image to be processed, and aiming at each row or each column, according to the sequence of continuous pixel point coordinates;
aiming at any target pixel point to be processed with the coordinate (i, j), executing according to the following process:
determining four pixel points of which the coordinates corresponding to the target pixel point to be processed are (i, j-1), (i-1, j) and (i-1, j +1) in sequence;
if no marked target pixel point exists in the four pixel points corresponding to the target pixel point to be processed, the marking value corresponding to the target pixel point to be processed is as follows: adding 1 to the current maximum mark value;
if at least one marked target pixel point exists in the four pixel points corresponding to the target pixel point to be processed, determining the minimum marking value in the marking values corresponding to the marked target pixel point as the marking value of the target pixel point to be processed;
updating the non-minimum mark value in the marked target pixel point to be the minimum mark value in the four pixel points corresponding to the target pixel point to be processed;
and determining a plurality of target pixel points with the same mark value as an initial pixel point group according to the mark value corresponding to each target pixel point to be processed to obtain a plurality of initial pixel point groups.
4. The method of claim 1, wherein fitting the pixels in the target pixel group to obtain a center and a radius of a fitting circle comprises:
determining second pixel points with the maximum value and the minimum value of coordinates in the horizontal direction and the vertical direction respectively according to the coordinates of a plurality of pixel points contained in each target pixel point group to obtain four second pixel points;
and determining the circle center and the radius of a fitting circle closest to the coordinates of the four second pixel points according to the coordinates of the four second pixel points.
5. An apparatus for analyzing mesoscale vortices, the apparatus comprising:
the acquisition unit is used for acquiring a synthetic aperture radar image to be processed; the synthetic aperture radar image to be processed comprises at least one mesoscale vortex to be analyzed;
a first determining unit, configured to determine, from the to-be-processed synthetic aperture radar image, a plurality of pixel points that constitute the at least one to-be-analyzed mesoscale vortex edge;
the analysis unit is used for analyzing the coordinates of a plurality of pixel points forming the edge of the at least one mesoscale vortex to be analyzed, and forming initial pixel point groups by the pixel points with continuous coordinates to obtain a plurality of initial pixel point groups;
the second determining unit is used for determining the longitude distance and the latitude distance of each initial pixel point group according to the longitude and latitude of the head pixel point and the tail pixel point in each initial pixel point group;
the third determining unit is used for determining that the longitude distance is greater than the average longitude distance, and the initial pixel group with the latitude distance greater than the average latitude distance is a target pixel group; the longitude distance average is: an average value of longitude distances of the initial pixel point group; the latitude distance average value is: an average value of the latitude distances of the initial pixel point group;
the fitting unit is used for fitting the pixels in the target pixel group to obtain the center and the radius of a fitting circle;
the fourth determining unit is used for determining the circle center and the radius of each fitting circle as the center and the radius of a mesoscale vortex;
a marking unit for marking a center of each mesoscale vortex in the synthetic aperture radar image to be processed.
6. The apparatus of claim 5, wherein the first determining unit comprises:
the first determining subunit is used for determining a plurality of first pixel points of a representation coastline belonging to a preset longitude and latitude coordinate range according to the longitude and latitude coordinates corresponding to each pixel point in the synthetic aperture radar image to be processed;
a second determining subunit, configured to determine, as a pixel to be processed, a pixel outside an area formed by the plurality of first pixels in the synthetic aperture radar image to be processed;
the third determining subunit is used for determining the gradient amplitude of each pixel point to be processed;
and the fourth determining subunit is used for determining a plurality of to-be-processed pixel points of which the gradient amplitudes belong to a preset gradient range as a plurality of pixel points representing the at least one to-be-analyzed mesoscale vortex edge.
7. The apparatus of claim 5, wherein the analysis unit comprises:
a fifth determining subunit, configured to sequentially determine, according to a preset sequence, a plurality of pixel points that constitute the at least one mesoscale vortex edge to be analyzed as target pixel points to be processed; the preset sequence comprises: according to the sequence of continuous rows or continuous columns in the synthetic aperture radar image to be processed, and aiming at each row or each column, according to the sequence of continuous pixel point coordinates;
the execution subunit is configured to execute, according to the following procedure, any target pixel point to be processed with the coordinate (i, j):
determining four pixel points of which the coordinates corresponding to the target pixel point to be processed are (i, j-1), (i-1, j) and (i-1, j +1) in sequence;
if no marked target pixel point exists in the four pixel points corresponding to the target pixel point to be processed, the marking value corresponding to the target pixel point to be processed is as follows: adding 1 to the current maximum mark value;
if at least one marked target pixel point exists in the four pixel points corresponding to the target pixel point to be processed, determining the minimum marking value in the marking values corresponding to the marked target pixel point as the marking value of the target pixel point to be processed;
updating the non-minimum mark value in the marked target pixel point to be the minimum mark value in the four pixel points corresponding to the target pixel point to be processed;
and determining a plurality of target pixel points with the same mark value as an initial pixel point group according to the mark value corresponding to each target pixel point to be processed to obtain a plurality of initial pixel point groups.
8. The apparatus of claim 5, wherein the fitting unit comprises:
a sixth determining subunit, configured to determine, for each target pixel point group, a second pixel point whose coordinate is the maximum value and the minimum value in the horizontal direction and the vertical direction, respectively, according to the coordinates of the plurality of pixel points included in the target pixel point group, and obtain four second pixel points;
and the seventh determining subunit is configured to determine, according to the coordinates of the four second pixel points, a circle center and a radius of a fitting circle closest to the coordinates of the four second pixel points.
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