CN113960610A - Seamless geocoding mapping method and system for side scan sonar - Google Patents
Seamless geocoding mapping method and system for side scan sonar Download PDFInfo
- Publication number
- CN113960610A CN113960610A CN202111058859.4A CN202111058859A CN113960610A CN 113960610 A CN113960610 A CN 113960610A CN 202111058859 A CN202111058859 A CN 202111058859A CN 113960610 A CN113960610 A CN 113960610A
- Authority
- CN
- China
- Prior art keywords
- image
- geocoding
- seamless
- fish
- scan sonar
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- 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
- G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
- G01S15/88—Sonar systems specially adapted for specific applications
- G01S15/89—Sonar systems specially adapted for specific applications for mapping or imaging
- G01S15/8902—Side-looking sonar
Abstract
The invention provides a seamless geocoding mapping method and a system of side scan sonar, wherein the method comprises the following steps: reading original data of the side scan sonar image, and forming a waterfall image through horizontal stacking; extracting channel data; carrying out quality control and interpolation on the channel data, and calculating the position of the fish-towing on the basis of the consistency of the heading of the fish-towing and the heading of the ship body; calculating the echo position of the side-scan sonar image according to the fish dragging position and the ship body course; determining an image range according to the echo position, setting the image resolution, and determining a pixel space of a coded image; traversing and extracting two pairs of adjacent echoes on adjacent scanning lines in the waterfall image, determining four-corner pixel positions of the two pairs of echoes on a pixel space, and constructing a local grid cache region covering the four-corner pixel positions; and scanning the local grid cache region, carrying out XOR operation on the scanning result to obtain a gap pixel set, and carrying out intensity assignment on the gap pixel set to obtain a seamless side-scan sonar geocoding image.
Description
Technical Field
The invention relates to the technical field of underwater sonar mapping, in particular to a seamless geocoding mapping method and system for a side scan sonar.
Background
The side scan sonar system scans seabed targets in a certain open angle range below the towed fish by adopting a double-linear array to form time sequence echoes distributed along an inclined distance, the time sequence echoes are represented as scanning lines in a vertical track direction with the towed fish as the center on an image, and the scanning lines are longitudinally stacked according to a navigation sequence to form a side scan sonar waterfall image.
The side scan sonar waterfall image does not have an intuitive position and orientation, and the waterfall image needs to be geocoded for convenient use. Limited by ship speed change and distance mapping, the resolution of side-scan sonar longitudinal and transverse echoes is inconsistent, and after geocoding, the adjacent scan lines of the side-scan sonar cannot realize full coverage mapping and gaps exist; in addition, since the side scan sonar uses an oblique distance map with the fish as the center, the course change can cause the generation of intersection or gap increase between adjacent scan lines.
In order to eliminate gaps on a side-scan sonar geocoded image, lower resolution is often adopted for geocoding to ensure that gaps among scanning lines on the image are as small as possible, and then filtering algorithms such as median and Gaussian are adopted to realize filling of the small gaps. The data of the side scan sonar with the upward vertical track has higher resolution, the processing mode can lose part of detail information in the original data, and when the course is obviously changed, the gaps and the crossing phenomenon of two side edges of a scanning line on a coded image can not be improved.
Disclosure of Invention
One of the main problems solved by the invention is how to eliminate the gap on the side-scan sonar geocoded image.
The invention provides a seamless geocoding mapping method of a side scan sonar, which comprises the following steps:
reading original data of the side scan sonar image, and forming a waterfall image through horizontal stacking;
extracting channel data in the original data;
performing quality control and interpolation on the channel data to obtain second channel data;
calculating the position of the fish towing according to the second channel data based on the consistency of the heading of the fish towing and the heading of the ship body;
calculating the echo position of the side-scan sonar image according to the fish dragging position and the ship body course;
determining an image range according to the echo position, setting the image resolution, and determining a pixel space of an encoded image according to the image range and the image resolution;
traversing and extracting two pairs of adjacent echoes on adjacent scanning lines in the waterfall image, determining four-corner pixel positions of the two pairs of echoes on the pixel space, and constructing a local grid cache region covering the four-corner pixel positions;
scanning the local grid cache region to obtain a scanning result, and performing exclusive-or operation on the scanning result to obtain a slit pixel set in the local grid cache region;
and carrying out intensity assignment on the gap pixel set to obtain a seamless side-scan sonar geocoding image.
Further, the forming the waterfall image by the horizontal stacking includes:
respectively extracting echo data of different channels, horizontally stacking the echo data of the port and starboard channels transmitted and received each time to form scanning line echoes, and vertically stacking all groups of the scanning line echoes along a flight path to form the waterfall image.
Further, the calculating the fish towing position according to the second channel data based on the consistency of the fish towing and the ship body heading comprises:
calculating the horizontal offset of the towed fish relative to the towing and hanging point of the ship body;
and obtaining the geographic coordinates of the towed fish through coordinate rotation according to the ship body course and the horizontal offset.
Further, the scanning the local grid cache region to obtain the scanning result further includes:
and determining the pixel serial number of the gap area by adopting an edge scanning method.
Further, the assigning the intensities of the slit pixel sets further includes:
and performing inverse distance weighting assignment on each pixel in the gap pixel set according to the echo intensity of the corner point at the position of the four corners of the pixel.
Further, the echo position of the side-scan sonar image calculated according to the fish dragging position and the ship body heading further comprises:
in the rectangular plane coordinate system, the central position of the scanning line is the position of a projection point right below the fish dragging.
According to an aspect of the present invention, a seamless geocoding mapping system for a side scan sonar is further disclosed, the seamless geocoding mapping system comprises a storage module, a processing module and an execution module, the storage module stores a computer program and image data, the processing module is used for processing the image data, the execution module is used for receiving the processed image data and calling the computer program to execute the seamless geocoding mapping method for a side scan sonar according to any one of claims 1 to 6.
The invention provides a seamless geocoding method and system suitable for a side-scan sonar image, wherein the method takes adjacent scanning lines as a geocoding unit, a pair of adjacent echo positions are respectively taken from the adjacent scanning lines each time to form a quadrilateral coding area, the serial number of each pixel in a quadrilateral is determined through pixel scanning, then the assignment of echo intensity is carried out, and the seamless geocoding imaging is further realized.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.
FIG. 1 is a schematic diagram of a side-scan sonar seamless geocoding imaging implementation flow in an embodiment of the invention.
Fig. 2 is a schematic diagram of the side-scan sonar echo geographic coordinate calculation principle and the map width range determination in the embodiment of the present invention.
FIG. 3 is a schematic diagram of the four-corner relationship between two adjacent pairs of echo patterns of adjacent scan lines according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating the determination of a set of slit pixels surrounded by two adjacent pairs of echoes according to an embodiment of the present invention.
FIG. 5 is a schematic diagram of a side-scan sonar seamless geocoding map in an embodiment of the invention.
Detailed Description
Various exemplary embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise.
Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description.
The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to specific embodiments and the accompanying drawings.
Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.
In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
As shown in fig. 1, it is a schematic diagram of the implementation flow of the side scan sonar seamless geocoding image of this embodiment.
Step one, reading original data to form a waterfall image.
The method comprises the steps of decoding original side scan sonar data, respectively extracting data such as echo intensity data, positioning data, course data and the like of different channels, horizontally stacking the echo data of the port and starboard channels which are transmitted and received each time to form a group of scanning line echoes, and vertically stacking the scanning line echoes along a track to form a waterfall image M multiplied by N, wherein M represents the number of longitudinal scanning lines, and N represents the number of transverse echoes of the waterfall image.
And step two, estimating the position and the course of the fish dragging.
And performing quality control and interpolation on the extracted positioning and heading data, and calculating the position of the fish dragging according to the heading consistency of the fish dragging and the ship body. Firstly, the horizontal offset of the towed fish relative to a towing point of a ship body is calculated according to the length of a towing cable and the vertical draft, and then the geographic coordinate of the towed fish is obtained through coordinate rotation according to instantaneous positioning data, the course and the horizontal offset of the towed fish of the ship body.
And step three, determining the position and the map range of each echo.
Calculating the geographic coordinate of each echo, and further determining the map range of the whole waterfall image; and reasonably setting the required mapping resolution to further determine the size of the coded image.
Specifically, the position of each echo of the side scan sonar is calculated based on the location and heading of the towed fish. In the rectangular plane coordinate system, the central position of the scanning line is the position of the projection point under the fish-towing line, as shown in fig. 2, the coordinate of the scanning central line position is the instantaneous geographic coordinate of the fish-towing line P0(X0,Y0)，X0And Y0Respectively as instantaneous fish towing echo point P0Geographic abscissa and ordinate. The single-side scanning amplitude of the side-scan sonar is R after the flat distance, the sampling rate of each channel is F, the instantaneous course is alpha, the azimuth angle of an echo sequence on the left side of a scanning line is theta-alpha-pi/2, the azimuth angle on the right side of the scanning line is theta-alpha + pi/2, and P is PiIs the ith echo of a certain side, then PiGeographic coordinates (X)i,Yi) Comprises the following steps:
based on the geographic coordinates of each echo, the geographic coordinate range of the side-scan sonar coded image can be determined to be (x)min,ymin；xmax,ymax). Setting the image forming resolution of the coded image as required, determining the geographic size Delta d corresponding to a single pixel of the image, and determining the echo point Pi(Xi,Yi) Corresponding pixel coordinate pi(xi,yi) Comprises the following steps:
and step four, searching and assigning the adjacent two scanning lines to the gap pixels surrounded by the two pairs of echoes.
Influenced by the difference of longitudinal and transverse resolution of side-scan sonar echoes, gaps are generated among scanning lines of the sonar image after geocoding, and the size of the gaps is not uniform at each position due to course change. Therefore, the assignment of the pixel positions of each echo calculated by formula (2) in step three is also needed to fill the gap, so as to form the side-scan sonar geocoded image shown in fig. 3.
First, the key to filling in a gap is to determine the position of the gap on the encoded image. Taking two pairs of adjacent echoes i and i +1 on adjacent scanning lines, determining the four-corner pixel position of the adjacent echoes on an encoding image, taking four echoes of i (j), i (j +1), i +1(j) and i +1(j +1), wherein j represents the number of the echoes, j +1 is more than or equal to 1 and less than or equal to N, and j +1 is more than or equal to 1 and less than or equal to M, and constructing a local grid cache region covering the four-corner echo position by using the four echoes; and respectively carrying out horizontal forward grid scanning on each side of the local grid cache region according to the method, and carrying out XOR operation on the scanning results of each side so as to determine a slit pixel set in the quadrangle region.
Specifically, during the geocoding process, a pair of adjacent echoes is taken from adjacent scanning lines each time along the extending direction of the scanning lines, and the position of the adjacent echoes on the graph, such as the corner point A on the scanning line A on the graph 2, is calculated1、A2And a corner point B on the scanning line B1、B2And the four corner points form a closed communication area, and the communication area is a gap area.
The pixel number of the void region is determined by using the edge scanning method, as shown in fig. 3, the flow is as follows:
cutting out A1、A2、B1And B2The value of each grid is 0;
② respectively using A2～A1、A1～B1、B1～B2、B2～A2The four edges are taken as reference lines, each pixel of the local grid is scanned along the positive horizontal direction, and the pixel scanned horizontally along each edge is assigned to be 1;
carrying out XOR operation [ ] on the scanning grid formed based on the four edges pairwise and pixel by pixel in sequence, wherein the operation rule is as follows:
0 0＝0； (3)
1 0＝1； (4)
1 1＝0； (5)
through the operation, the area with the grid value of 1 is the gap grid surrounded by the four echoes, and a gap pixel set is obtained through grid logic search.
And then carrying out inverse distance weighting assignment on the obtained slit pixel set.
In particular, according to A1、A2And B1、B2And carrying out inverse distance weighting assignment on the determined gap pixel set according to the echo intensities of the four corner points. If the echo intensities of the four angular points are I respectivelya1、Ia2、Ib1、Ib2For any slit pixel P (i, j) in the local grid, the distance S between the slit pixel P (i, j) and four corner points can be calculateda1、Sa2、Sb1、Sb2And further determining the assigned intensity I of the gap pixel as:
and step five, repeating the process of the step four until the side scan sonar image geocoding is completed.
Specifically, all two adjacent scan lines and two adjacent echoes on each scan line are traversed, every four echoes form a group, and each group of echoes is scanned and filled once. And repeating the step four, filling gaps in the coded image to form a seamless side-scan sonar geocoded image, and forming a picture image as shown in fig. 5.
In the process of traversing each echo by the side-scan sonar geocoding, all pixel areas which possibly generate gaps are processed, so that the side-scan sonar geocoding image can be completely seamless; meanwhile, the changes of factors such as course, ship speed, water depth and the like are not considered, the limitation of the resolution of the formed image is avoided, and the upward detailed information of the vertical track of the side scan sonar can be reserved to the greatest extent.
The above description is only exemplary of the present invention and should not be taken as limiting the invention, as any modification, equivalent replacement, or improvement made within the spirit and scope of the present invention should be included in the present invention.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in the process, method, article, or apparatus that comprises the element.
Claims (7)
1. A seamless geocoding mapping method of side scan sonar is characterized by comprising the following steps:
reading original data of the side scan sonar image, and forming a waterfall image through horizontal stacking;
extracting channel data in the original data;
performing quality control and interpolation on the channel data to obtain second channel data;
calculating the position of the fish towing according to the second channel data based on the consistency of the heading of the fish towing and the heading of the ship body;
calculating the echo position of the side-scan sonar image according to the fish dragging position and the ship body course;
determining an image range according to the echo position, setting the image resolution, and determining a pixel space of an encoded image according to the image range and the image resolution;
traversing and extracting two pairs of adjacent echoes on adjacent scanning lines in the waterfall image, determining four-corner pixel positions of the two pairs of echoes in the pixel space, and constructing a local grid cache region covering the four-corner pixel positions;
scanning the local grid cache region to obtain a scanning result, and performing exclusive-or operation on the scanning result to obtain a slit pixel set in the local grid cache region;
and carrying out intensity assignment on the gap pixel set to obtain a seamless side-scan sonar geocoding image.
2. The seamless geocoding mapping method of claim 1, wherein the forming a waterfall image by horizontal stacking comprises:
respectively extracting echo data of different channels, horizontally stacking the echo data of the port and starboard channels transmitted and received each time to form scanning line echoes, and vertically stacking all groups of the scanning line echoes along a flight path to form the waterfall image.
3. The seamless geocoding mapping method of claim 1, wherein calculating a fish towing location from the second channel data based on consistency of fish towing and hull heading comprises:
calculating the horizontal offset of the towed fish relative to the towing and hanging point of the ship body;
and obtaining the geographic coordinates of the towed fish through coordinate rotation according to the ship body course and the horizontal offset.
4. The method of seamless geocoding mapping of claim 1, wherein scanning the local grid cache to obtain a scan result further comprises:
and determining the pixel serial number of the gap area by adopting an edge scanning method.
5. The method of seamless geocoding mapping of claim 1, wherein said assigning intensities to the set of gap pixels further comprises:
and performing inverse distance weighting assignment on each pixel in the gap pixel set according to the echo intensity of the corner point at the position of the four corners of the pixel.
6. The seamless geocoding imaging method of claim 5, wherein said calculating an echo location of the side-scan sonar image from the fish-dragging location and the hull heading further comprises:
in the rectangular plane coordinate system, the central position of the scanning line is the position of a projection point right below the fish dragging.
7. A seamless geocoding imaging system for side scan sonar, comprising a storage module, a processing module and an execution module, wherein the storage module stores a computer program, the processing module is used for processing image data of pre-imaging, and the execution module is used for receiving the image data and calling the computer program to execute the seamless geocoding imaging method for side scan sonar according to any one of claims 1-6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111058859.4A CN113960610A (en) | 2021-09-09 | 2021-09-09 | Seamless geocoding mapping method and system for side scan sonar |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111058859.4A CN113960610A (en) | 2021-09-09 | 2021-09-09 | Seamless geocoding mapping method and system for side scan sonar |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113960610A true CN113960610A (en) | 2022-01-21 |
Family
ID=79461217
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111058859.4A Pending CN113960610A (en) | 2021-09-09 | 2021-09-09 | Seamless geocoding mapping method and system for side scan sonar |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113960610A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115469315A (en) * | 2022-11-02 | 2022-12-13 | 广东智能无人系统研究院 | Sonar imaging method adopting inclined side scanning mode |
-
2021
- 2021-09-09 CN CN202111058859.4A patent/CN113960610A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115469315A (en) * | 2022-11-02 | 2022-12-13 | 广东智能无人系统研究院 | Sonar imaging method adopting inclined side scanning mode |
| CN115469315B (en) * | 2022-11-02 | 2023-03-10 | 广东智能无人系统研究院 | Sonar imaging method adopting inclined side scanning mode |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110969624B (en) | Laser radar three-dimensional point cloud segmentation method | |
| US20170140514A1 (en) | Image synthesis utilizing an active mask | |
| CN113516769B (en) | Virtual reality three-dimensional scene loading and rendering method and device and terminal equipment | |
| CN112560671B (en) | Ship detection method based on rotary convolution neural network | |
| CN105699951B (en) | Marine radar analogue echoes method based on dem data superposition | |
| CN108564532B (en) | Large-scale ground distance satellite-borne SAR image mosaic method | |
| CN104778695A (en) | Water sky line detection method based on gradient saliency | |
| CN113657252B (en) | Efficient SAR image ship target detection method based on encoding and decoding device | |
| CN107103610B (en) | automatic detection method for suspicious region matched with satellite images in stereo mapping | |
| CN110428425A (en) | A kind of SAR image sea land separation method based on coastline vector data | |
| Hurtós et al. | A novel blending technique for two-dimensional forward-looking sonar mosaicing | |
| CN113960610A (en) | Seamless geocoding mapping method and system for side scan sonar | |
| CN114926739B (en) | Unmanned collaborative acquisition processing method for geographical space information on water and under water of inland waterway | |
| CN112257721A (en) | Image target region matching method based on Fast ICP | |
| CN101383046A (en) | Three-dimensional reconstruction method on basis of image | |
| CN108399602B (en) | Joint splicing method for large-area multi-strip side-scan sonar images | |
| CN113805178A (en) | Method for detecting static obstructive objects on water surface | |
| CN113837924A (en) | Water bank line detection method based on unmanned ship sensing system | |
| KR20130096432A (en) | A system and method for generating underwater geospatial information using the ground slope under the sea | |
| CN116957935A (en) | Side-scan sonar stripe image stitching method based on path line constraint | |
| CN116990824A (en) | Graphic geographic information coding and fusion method of cluster side scanning system | |
| CN110174109B (en) | Unmanned ship multi-element combined navigation method based on sea-air coordination | |
| CN114863258B (en) | Method for detecting small target based on visual angle conversion in sea-sky-line scene | |
| CN110189403B (en) | Underwater target three-dimensional reconstruction method based on single-beam forward-looking sonar | |
| Gracias et al. | Application challenges of underwater vision |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |