Three-Dimensional Reconstruction Based on Visual SLAM of Mobile Robot in Search and Rescue Disaster Scenarios

Abstract

SummaryConventional simultaneous localization and mapping (SLAM) has concentrated on two-dimensional (2D) map building. To adapt it to urgent search and rescue (SAR) environments, it is necessary to combine the fast and simple global 2D SLAM and three-dimensional (3D) objects of interest (OOIs) local sub-maps. The main novelty of the present work is a method for 3D OOI reconstruction based on a 2D map, thereby retaining the fast performances of the latter. A theory is established that is adapted to a SAR environment, including the object identification, exploration area coverage (AC), and loop closure detection of revisited spots. Proposed for the first is image optical flow calculation with a 2D/3D fusion method and RGB-D (red, green, blue + depth) transformation based on Joblove–Greenberg mathematics and OpenCV processing. The mathematical theories of optical flow calculation and wavelet transformation are used for the first time to solve the robotic SAR SLAM problem. The present contributions indicate two aspects: (i) mobile robots depend on planar distance estimation to build 2D maps quickly and to provide SAR exploration AC; (ii) 3D OOIs are reconstructed using the proposed innovative methods of RGB-D iterative closest points (RGB-ICPs) and 2D/3D principle of wavelet transformation. Different mobile robots are used to conduct indoor and outdoor SAR SLAM. Both the SLAM and the SAR OOIs detection are implemented by simulations and ground-truth experiments, which provide strong evidence for the proposed 2D/3D reconstruction SAR SLAM approaches adapted to post-disaster environments.

Finite Element Analysis of Femoral-Acetabular Impingement (FAI) Based on Three-Dimensional Reconstruction

“…With the in-depth study of the disease, certain acquired factors will cause changes in the anatomical structure of the hip joint, which will also become the cause of FAI [17]. In addition, studies have shown that even if the anatomical structure of the hip joint does not have the above abnormal performance, when its range of motion exceeds the normal range, there will be "impact" between the proximal femur and the acetabular rim, which to some extent also confirms GANZ on the basis of the pathogenesis of the disease, that is, the theoretical view of the abnormal hip joint structure [18].…”

Head CT Image Segmentation and Three-Dimensional Reconstruction Technology Based on Human Anatomy

“…Finally, the 3D reconstruction results with higher precision surface normals and better quality were successfully obtained [ 13 ]. Wang et al believed that the two-dimensional image has the characteristics of fast but simple, so they applied the mobile robot vision technology to it, improved it, proposed the three-dimensional reconstruction technology, and verified the efficiency and accuracy of the three-dimensional reconstruction technology through simulation analysis [ 14 ]. Ruiz et al proposed a nonrigid object 3D reconstruction algorithm using depth camera, which can dynamically construct the dense 3D model of the target object, improve the accuracy of 3D reconstruction, and can be applied to many fields such as medicine, agriculture, and human-computer interaction [ 15 ].…”

Mobile Manipulation Integrating Enhanced AMCL High-Precision Location and Dynamic Tracking Grasp

“…Kohlbrecher et al [ 35 ] described a Hector-SLAM-based [ 36 ] open-source SLAM system for urban search-and-rescue missions, which enables robots to map and locate themselves in a degraded urban environment, and independently explore disaster sites to identify victims and other interesting objects. Similarly, Wang et al [ 37 ] used optical flow calculation and wavelet transformation to solve the problem of SLAM in emergency search-and-rescue environments. The three-dimensional (3D) reconstruction, based on RGB-D information, is carried out by combining a two-dimensional (2D) map and three-dimensional objects in order to realize the positioning of the robot in unfamiliar environments.…”