Underwater structured environment line feature extraction method based on forward looking sonar

A technology of underwater structure and extraction method, which is applied in the direction of sound wave re-radiation, radio wave measurement system, utilization of re-radiation, etc., can solve problems such as easy ambiguity, low efficiency, poor real-time performance, etc., to overcome blindness and ambiguity performance, improve execution efficiency and real-time effect

Active Publication Date: 2018-05-22
HARBIN ENG UNIV
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Problems solved by technology

[0004] The purpose of the present invention is to provide a method for extracting underwater structured environmental line features based on forward-looking sonar in order t

Method used

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  • Underwater structured environment line feature extraction method based on forward looking sonar
  • Underwater structured environment line feature extraction method based on forward looking sonar
  • Underwater structured environment line feature extraction method based on forward looking sonar

Examples

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Example Embodiment

[0062] Example 1: Combination Figure 1 to Figure 6 The method for extracting features of underwater structured environment lines based on forward-looking sonar of the present invention includes:

[0063] Step 1: Perform dynamic threshold segmentation on the forward looking sonar data to obtain the total number of high echo intensity points and their polar coordinates under the load system;

[0064] Step 2: Randomly select two non-isolated and non-adjacent points from the high echo intensity points within a limited number of cycles to construct a straight line, select the points whose distance to the straight line is less than the preset threshold to form a candidate point set, and calculate the candidate point set The ratio of the potential of to the total number of points. If the ratio is not less than the threshold, use the straight line as an auxiliary straight line and terminate the loop;

[0065] Step 3: Based on the auxiliary line parameters and the corresponding candidate po...

Example Embodiment

[0068] Embodiment 2: Based on the above embodiment, step one is specifically:

[0069] Step 1: Collect forward-looking sonar data within a certain range of sonar opening angle, perform dynamic threshold segmentation on the forward-looking sonar data, obtain high echo intensity points and calculate the number of high echo intensity points.

[0070] It should be noted that the forward looking sonar in the present invention mainly refers to a single-beam mechanical scanning imaging sonar and a 2D multi-beam imaging sonar. Both types of sonar realize environmental detection by detecting the echo intensity at equally spaced points within the detection range. The relative position of the origin of their detection beam under the carrier system is as follows: figure 1 with figure 2 Shown. For example, a single-beam mechanical scanning imaging sonar continuously emits a beam and scans in a certain direction. The detection distance of the sonar beam is 50m, and the sonar will return to the...

Example Embodiment

[0079] Embodiment 3: Based on the above embodiment, step 2 is specifically:

[0080] Step 2: Set the maximum number of calculations for the auxiliary line.

[0081] In order to obtain the auxiliary line required in the subsequent steps in a short time, the algorithm must complete the calculation of the auxiliary line within a limited number of times, so a small fixed value not exceeding 10 is set as the maximum number of calculations of the auxiliary line.

[0082] Step 2: Two points are randomly selected from the high echo intensity points. The selected point cannot be the only isolated point on the entire beam with an echo intensity greater than the threshold, and it should satisfy that the point is two adjacent positions on the beam The echo intensity of is greater than the threshold; and the two selected points are on two different beams, and the two beams are separated by at least a certain number of beams. The setting of the separation is determined by factors such as the total...

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Abstract

The invention provides an underwater structured environment line feature extraction method based on forward looking sonar. The method comprises steps: dynamic threshold segmentation is carried out onforward looking sonar data to acquire the total number of high echo intensity points and polar coordinates in a carrier system; within the limited cycle times, two not-isolated and not-adjacent pointsare randomly selected from the high echo intensity points to form a straight line, points with the distances with the straight line smaller than a preset threshold are selected to form a candidate point set, the ratio of the potential of the candidate point set to the total point number is calculated, if the ratio is no smaller than the threshold, the straight line is used as an auxiliary straight line, and the cycle is stopped; based on the parameters of the auxiliary straight line and the corresponding candidate point set distribution features, the voting space for structured environment line feature parameters is constructed, and a voting algorithm is used to extract line feature parameters; and based on the distribution condition of points near the line features, the line features arecut to line section features. The blindness of random sampling and the inefficiency of the voting algorithm can be overcome effectively.

Description

technical field [0001] The invention relates to a method for extracting features of underwater structured environment lines based on forward-looking sonar, and belongs to the field of intelligent perception and modeling of underwater environment acoustics. Background technique [0002] For robots, the ability to perceive and understand the underwater environment is an important factor that restricts the level of autonomy and intelligence of robots. Underwater structured environments such as ports and waterways are common working scenarios for underwater robots. Underwater robots usually detect these underwater structured buildings based on forward-looking sonar and describe them with line segments. Therefore, an accurate and efficient underwater structured environment line feature extraction algorithm is the fundamental guarantee for underwater robots to understand the underwater structured environment in real time and correctly. [0003] However, the current algorithm for ...

Claims

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Application Information

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IPC IPC(8): G01S15/89
CPCG01S15/89
Inventor 张强牛伯城李晔盛明伟张雯隋炎橙马腾范彦福张国成曹建
Owner HARBIN ENG UNIV
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