A Review of Point Feature Based Medical Image Registration

Point features, as the basis of lines, surfaces, and bodies, are commonly used in medical image registration. To obtain an elegant spatial transformation of extracted feature points, many point set matching algorithms(PMs) have been developed to match two point sets by optimizing multifarious distance functions. There are ample reviews related to medical image registration and PMs which summarize their basic principles and main algorithms separately. However,to data, detailed summary of PMs used in medical image registration in different clinical environments has not been published. In this paper, we provide a comprehensive review of the existing key techniques of the PMs applied to medical image registration according to the basic principles and clinical applications. As the core technique of the PMs, geometric transformation models are elaborated in this paper, demonstrating the mechanism of point set registration. We also focus on the clinical applications of the PMs and propose a practical classification method according to their applications in different clinical surgeries. The aim of this paper is to provide a summary of pointfeaturebased methods used in medical image registration and to guide doctors or researchers interested in this field to choose appropriate techniques in their research.

Current Researches and Future Development Trend of Intelligent Robot: A Review

With the advancing of industrialization and the advent of the information age, intelligent robots play an increasingly important role in intelligent manufacturing, intelligent transportation system, the Internet of things, medical health and intelligent services. Based on working experiences in and reviews on intelligent robot studies both in China and abroad, the authors summarized researches on key and leading technologies related to human-robot collaboration, driverless technology, emotion recognition, brain-computer interface, bionic software robot and cloud platform, big data network, etc. The development trend of intelligent robot was discussed, and reflections on and suggestions to intelligent robot development in China were proposed. The review is not only meant to overview leading technologies of intelligent robot all over the world, but also provide related theories, methods and technical guidance to the technological and industrial development of intelligent robot in China.

智能无人自主系统发展趋势（英文）

智能无人自主系统是人工智能的重要应用之一,其发展可大大推动人工智能技术的创新。本文通过其主要成就介绍了智能无人自主系统的发展趋势。并且,本文将相关技术分成了7个领域,包括人工智能技术、无人车、无人机、服务机器人、空间机器人、海洋机器人和无人车间/智能工厂。本文对每个领域的发展趋势进行了介绍。

Multi-UAV collaborative system with a feature fast matching algorithm

We present a real-time monocular simultaneous localization and mapping(SLAM)system with a new distributed structure for multi-UAV collaboration tasks.The system is different from other general SLAM systems in two aspects:First,it does not aim to build a global map,but to estimate the latest relative position between nearby vehicles;Second,there is no centralized structure in the proposed system,and each vehicle owns an individual metric map and an ego-motion estimator to obtain the relative position between its own map and the neighboring vehicles'.To realize the above characteristics in real time,we demonstrate an innovative feature description and matching algorithm to avoid catastrophic expansion of feature point matching workload due to the increased number of UAVs.Based on the hash and principal component analysis,the matching time complexity of this algorithm can be reduced from 0(logN)to 0(1).To evaluate the performance,the algorithm is verified on the acknowledged multi-view stereo benchmark dataset,and excellent results are obtained.Finally,through the simulation and real flight experiments,this improved SLAM system with the proposed algorithm is validated.

Bearing-only Visual SLAM for Small Unmanned Aerial Vehicles in GPS-denied Environments

This paper presents a hierarchical simultaneous localization and mapping（SLAM） system for a small unmanned aerial vehicle（UAV） using the output of an inertial measurement unit（IMU） and the bearing-only observations from an onboard monocular camera.A homography based approach is used to calculate the motion of the vehicle in 6 degrees of freedom by image feature match.This visual measurement is fused with the inertial outputs by an indirect extended Kalman filter（EKF） for attitude and velocity estimation.Then,another EKF is employed to estimate the position of the vehicle and the locations of the features in the map.Both simulations and experiments are carried out to test the performance of the proposed system.The result of the comparison with the referential global positioning system/inertial navigation system（GPS/INS） navigation indicates that the proposed SLAM can provide reliable and stable state estimation for small UAVs in GPS-denied environments.

An untethered cable-driven ankle exoskeleton with plantarflexion-dorsiflexion bidirectional movement assistance

Lower-limb assisted exoskeletons are widely researched for movement assistance or rehabilitation training.Due to advantages of compliance with human body and lightweight,some cable-driven prototypes have been developed,but most of these can assist only unidirectional movement.In this paper we present an untethered cable-driven ankle exoskeleton that can achieve plantarflexion-dorsiflexion bidirectional motion bilaterally using a pair of single motors.The main weights of the exoskeleton,i.e.,the motors,power supplement units,and control units,were placed close to the proximity of the human body,i.e.,the waist,to reduce the redundant rotation inertia which would apply on the wearer’s leg.A cable force transmission system based on gear-pulley assemblies was designed to transfer the power from the motor to the end-effector effectively.A cable self-tension device on the power output unit was designed to tension the cable during walking.The gait detection system based on a foot pressure sensor and an inertial measurement unit(IMU)could identify the gait cycle and gait states efficiently.To validate the power output performance of the exoskeleton,a torque tracking experiment was conducted.When the subject was wearing the exoskeleton with power on,the muscle activity of the soleus was reduced by 5.2%compared to the state without wearing the exoskeleton.This preliminarily verifies the positive assistance effect of our exoskeleton.The study in this paper demonstrates the promising application of a lightweight cable-driven exoskeleton on human motion augmentation or rehabilitation.