Robot slam method and system for outdoor feature sparse environment

A robotic and sparse technology, applied to instruments, computer components, calculations, etc., can solve problems such as errors, unstable features, and blurred descriptions of visual features, and achieve the effects of improving positioning capabilities, high operating efficiency, and strong promotion

Active Publication Date: 2022-08-02
SHANGHAI JIAO TONG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The publication number is CN110309834A (application number: 201910393343.1), which discloses a SLAM algorithm for outdoor offline navigation. A certain number of feature points are obtained through a locally adaptive threshold adjustment algorithm, which overcomes the shadows and weak lighting in the images of wild scenes. The problem of insufficient accuracy of feature point extraction under the conditions of objective factors such as sudden noise and sudden noise
This method does not fundamentally solve the problems of difficult feature extraction and drastic illumination changes in the outdoor environment with sparse features. For the sparse environment, lowering the feature detection threshold will bring feature instability, which will cause greater errors; and use multi-scale detection. The method of the method is relatively vague for the description of visual features, and cannot accurately measure the weight of image features in optimization.

Method used

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  • Robot slam method and system for outdoor feature sparse environment
  • Robot slam method and system for outdoor feature sparse environment
  • Robot slam method and system for outdoor feature sparse environment

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Embodiment 1

[0094] The task of the present invention is to face the outdoor feature sparse environment, aiming at the problems existing in the current robot real-time positioning and mapping algorithm, to provide a method to eliminate the influence of the scene image information by the drastic changes of the lighting conditions through image preprocessing, and improve the feature extraction algorithm by improving the feature extraction algorithm. To obtain more robust and uniform features, use the visual loss weight optimization algorithm based on IMU pre-integration for the globally extracted image features to optimize the visual loss function, and then obtain more accurate robot positioning and mapping results.

[0095] According to a robot SLAM method for outdoor feature sparse environment provided by the present invention, such as Figures 1 to 5 shown, including:

[0096] According to the provisions of the present invention, the system needs to input the collected environmental image...

Embodiment 2

[0221] Example 2 is a modification of Example 1

[0222] The positioning and mapping algorithm of the present invention includes three parts: (1) image preprocessing in an outdoor feature sparse environment; (2) block SIFT feature extraction; (3) visual loss weight optimization based on IMU pre-integration, which consists of the following steps composition:

[0223] Step 1.1: Use the CLAHE local histogram equalization algorithm for images in an outdoor feature sparse environment;

[0224] Step 1.2: Use the histogram equalization algorithm on the image after partial equalization.

[0225] Step 2.1: Divide the image into small blocks, and extract SIFT features in the small blocks respectively;

[0226] Step 2.2: All the features are allocated by quadtree. There are two left and right image blocks in the initial image. When the number of feature points in the image block is not less than 4, the left and right and top and bottom are divided into four small image blocks on averag...

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Abstract

The invention provides a visual inertial SLAM method and system for a mobile robot in an outdoor feature sparse environment, including: acquiring an environmental image in an outdoor feature sparse environment, preprocessing the environmental image, and obtaining the preprocessed environmental image ; Extract the sparse features of the pre-processed environment image by the block SIFT feature extraction algorithm; estimate the inter-frame motion of the robot through the pre-integration of the inertial unit IMU, and estimate the inter-frame displacement of the matching points, and the sparseness is determined by the size of the displacement. The importance of the feature is judged, and the visual reprojection error is calculated; the IMU error is accumulated according to the variance in the IMU pre-integration process; the loss function is jointly constructed according to the visual reprojection error and the IMU error; the loss function is minimized by the nonlinear optimization method, Solve the robot's pose transformation and map point space coordinates. The present invention can reduce the influence of difficulties such as drastic changes in illumination and sparse features on the positioning performance, and improve the autonomy of the mobile robot in a complex outdoor environment.

Description

technical field [0001] The invention relates to a real-time positioning and mapping algorithm of a robot, in particular, to a robot SLAM method and system for an outdoor feature sparse environment, and more particularly, to a robot visual inertia for an outdoor feature sparse environment Real-time positioning and mapping algorithm, using image preprocessing, feature detection, and optimizing the weight of visual error loss to improve the robot's positioning and mapping ability in outdoor scenes with sparse features. Background technique [0002] The general SLAM problem is aimed at scenes with relatively closed environments and rich environmental features such as indoors and streets. In outdoor environments with sparse features (such as deserts, beaches, rocky beaches, planets and lunar surfaces, etc.), the problem of real-time robot positioning and mapping is related to the autonomous positioning, safety, and mission planning of robots in such scenarios, especially When th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01C21/32G06V20/00G06V10/46G06V10/50
CPCG01C21/32G06V20/00G06V10/50G06V10/462
Inventor 陈卫东田琛晟王景川
Owner SHANGHAI JIAO TONG UNIV
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