Monocular SLAM scale recovery method

Abstract

The invention discloses a monocular SLAM scale recovery method, which comprises the following steps: manufacturing a calibration box, wherein a rectangular through hole is formed in the calibration box in a penetrating mode; placing a calibration box at the visual field of the monocular camera, wherein the monocular camera models a target object after passing through a through hole of the calibration box; enabling the monocular camera to perform image acquisition on the inner wall of the calibration box, and performing region segmentation to obtain upper and lower surface images of the inner wall of the calibration box in the first few key frames generated by the SLAM; obtaining three-dimensional map point coordinates of the upper and lower images of the inner wall of the calibration box according to the corresponding relation between the feature points and the three-dimensional map points in the SLAM; fitting three-dimensional map point coordinates of the upper and lower surfaces of the inner wall of the calibration box by using two-plane horizontal behavior constraint conditions, and calculating and obtaining distances between the upper and lower surfaces of the inner wall of thecalibration box in a three-dimensional map; calculating a scale factor; and recovering the whole three-dimensional map scale by using the scale factor F. The monocular SLAM scale in the human intestinal environment can be automatically recovered, the effect is good, and the precision is high.

Description

technical field [0001] The invention relates to the technical field of surgical robot navigation, in particular to a method for restoring monocular SLAM scale. Background technique [0002] In the process of taking photos with a monocular camera, the actual distance from the object to the camera cannot be known only by a single photo. In monocular vision SLAM, the distance between the object and the camera is solved by triangulating the matched feature points in adjacent key frames. The distance of the camera, the measured distance is only a value, without any unit, and the scale is uncertain, so it only restores the structural frame of the object, not the actual size of the object. [0003] At present, other sensors are mainly added to restore the scale in the large scene environment, such as combining IMU, GPS and lidar, etc.; using the scale information provided by additional sensors can restore the absolute scale with high accuracy. Due to the limitation of sensor size, ...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a method for monocular SLAM scale recovery, which can solve the problem of monocular SLAM scale uncertainty in the human intestinal environment

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