scholarly journals Cartographer SLAM Method for Optimization with an Adaptive Multi-Distance Scan Scheduler

2020 ◽  
Vol 10 (1) ◽  
pp. 347 ◽  
Author(s):  
Abdurahman Dwijotomo ◽  
Mohd Azizi Abdul Rahman ◽  
Mohd Hatta Mohammed Ariff ◽  
Hairi Zamzuri ◽  
Wan Muhd Hafeez Wan Azree
Keyword(s):  
Processing Speed ◽  
Short Distance ◽  
Scheduling Algorithms ◽  
Adaptive Method ◽  
Search Window ◽  
Performance Time ◽  
Localization And Mapping ◽  
Improved Performance ◽  
Similar Accuracy ◽  
Map Data

This paper presents the use of Google’s simultaneous localization and mapping (SLAM) technique, namely Cartographer, and adaptive multistage distance scheduler (AMDS) to improve the processing speed. This approach optimizes the processing speed of SLAM which is known to have performance degradation as the map grows due to a larger scan matcher. In this proposed work, the adaptive method was successfully tested in an actual vehicle to map roads in real time. The AMDS performs a local pose correction by controlling the LiDAR sensor scan range and scan matcher search window with the help of scheduling algorithms. The scheduling algorithms manage the SLAM that swaps between short and long distances during map data collection. As a result, the algorithms efficiently improved performance speed similar to short distance LiDAR scans while maintaining the accuracy of the full distance of LiDAR. By swapping the scan distance of the sensor, and adaptively limiting the search size of the scan matcher to handle difference scan sizes, the pose’s generation performance time is improved by approximately 16% as compared with a fixed scan distance, while maintaining similar accuracy.

scholarly journals Can Intentional Distractions Affect Endurance Performance Positively?

2021 ◽  
Vol 4 (1) ◽  
pp. 15
Author(s):  
Roger Couture
Keyword(s):  
Perceived Exertion ◽  
Endurance Performance ◽  
Residual Effects ◽  
Ratings Of Perceived Exertion ◽  
Future Studies ◽  
Performance Time ◽  
Performance Change ◽  
Confounding Variables ◽  
Improved Performance ◽  
Active Distraction

Distractions are often associated with negative outcomes however, distractions can also benefit people. Using the hypothesis of internal-external distractions in the competition for cue, this study examined the effects of an active (controlled) and passive (uncontrolled) distraction on three endurance tasks. Participants (N=42), aged 20 to 23 years were assigned to three groups. Tasks and conditions were counterbalanced across groups to minimize the residual effects of fatigue, learning an intervention and other confounding variables. Performance time, heart rate, ratings of perceived exertion and perceived fatigue were measured. Results showed that active distraction significantly improved performance and lowered Rate of Perceived Exertion in one task. As expected, the active distraction group was the least accurate for estimating time spent. Passive distraction caused minimal performance change. More investigation is needed to understand why an active distraction only affected one trial. Future studies should delve into means for better understanding the hypothesis of competition for cue.

Evaluation of the effects of adding vibrotactile feedback to myoelectric prosthesis users on performance and visual attention in a dual-task paradigm

2018 ◽  
Vol 32 (10) ◽  
pp. 1308-1316 ◽  
Author(s):  
Eitan Raveh ◽  
Jason Friedman ◽  
Sigal Portnoy
Keyword(s):  
Visual Attention ◽  
Dual Task ◽  
Repeated Measures ◽  
Gaze Behavior ◽  
Vibrotactile Feedback ◽  
Myoelectric Prosthesis ◽  
Repeated Measures Design ◽  
Performance Time ◽  
Dual Task Paradigm ◽  
Improved Performance

Objective: To evaluate the effects of adding vibrotactile feedback to myoelectric prosthesis users on the performance time and visual attention in a dual-task paradigm. Design: A repeated-measures design with a counterbalanced order of two conditions. Setting: Laboratory setting. Subjects: Transradial amputees using a myoelectric prosthesis with normal or corrected eyesight ( N = 12, median age = 65 ± 13 years). Exclusion criteria were orthopedic or neurologic problems. Interventions: Subjects performed grasping tasks with their prosthesis, while controlling a virtual car on a road with their intact hand. The dual task was performed twice: with and without vibrotactile feedback. Main measures: Performance time of each of the grasping tasks and gaze behavior, measured by the number of times the subjects shifted their gaze toward their hand, the relative time they applied their attention to the screen, and percentage of error in the secondary task. Results: The mean performance time was significantly shorter ( P = 0.024) when using vibrotactile feedback (93.2 ± 9.6 seconds) compared with the performance time measured when vibrotactile feedback was not available (107.8 ± 20.3 seconds). No significant differences were found between the two conditions in the number of times the gaze shifted from the screen to the hand, in the time the subjects applied their attention to the screen, and in the time the virtual car was off-road, as a percentage of the total game time (51.4 ± 15.7 and 50.2 ± 19.5, respectively). Conclusion: Adding vibrotactile feedback improved performance time during grasping in a dual-task paradigm. Prosthesis users may use vibrotactile feedback to perform better during daily tasks, when multiple cognitive demands are present.

scholarly journals A Low-Cost Consistent Vehicle Localization Based on Interval Constraint Propagation

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Zhan Wang ◽  
Alain Lambert
Keyword(s):  
Constraint Satisfaction Problem ◽  
Low Cost ◽  
Dead Reckoning ◽  
Constraint Propagation ◽  
Vehicle Localization ◽  
Practical Applications ◽  
Localization And Mapping ◽  
Position And Orientation ◽  
Map Data ◽  
Interval Constraint

Probabilistic techniques (such as Extended Kalman Filter and Particle Filter) have long been used to solve robotic localization and mapping problem. Despite their good performance in practical applications, they could suffer inconsistency problems. This paper proposes an interval analysis based method to estimate the vehicle pose (position and orientation) in a consistent way, by fusing low-cost sensors and map data. We cast the localization problem into an Interval Constraint Satisfaction Problem (ICSP), solved via Interval Constraint Propagation (ICP) techniques. An interval map is built when a vehicle embedding expensive sensors navigates around the environment. Then vehicles with low-cost sensors (dead reckoning and monocular camera) can use this map for ego-localization. Experimental results show the soundness of the proposed method in achieving consistent localization.

scholarly journals Online cognitive training in healthy older adults: a preliminary study on the effects of single versus multi-domain training

2015 ◽  
Vol 6 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Courtney C Walton ◽  
Alexandra Kavanagh ◽  
Luke A. Downey ◽  
Justine Lomas ◽  
David A Camfield ◽  
...  
Keyword(s):  
Older Adults ◽  
Active Control ◽  
Cognitive Training ◽  
Processing Speed ◽  
Future Research ◽  
Control Group ◽  
Control Groups ◽  
Healthy Older Adults ◽  
Short Period ◽  
Improved Performance

AbstractIt has been argued that cognitive training may be effective in improving cognitive performance in healthy older adults. However, inappropriate active control groups often hinder the validity of these claims. Additionally there are relatively few independent empirical studies on popular commercially available cognitive training programs. The current research extends on previous work to explore cognitive training employing a more robust control group. Twenty-eight healthy older adults (age: M = 64.18, SD = 6.9) completed either a multi-faceted online computerised cognitive training program or trained on a simple reaction time task for 20 minutes a day over a 28 day period. Both groups significantly improved performance in multiple measures of processing speed. Only the treatment group displayed improved performance for measures of memory accuracy. These results suggest improvements in processing speed and visual working memory may be obtained over a short period of computerized cognitive training. However, gains over this time appear only to show near transfer. The use of similar active control groups in future research are needed in order to better understand changes in cognition after cognitive training.

scholarly journals Visual analytics of 3D LiDAR point clouds in robotics operating systems

2020 ◽  
Vol 9 (2) ◽  
Author(s):  
Alia Mohd Azri ◽  
Shuzlina Abdul-Rahman ◽  
Raseeda Hamzah ◽  
Zalilah Abd Aziz ◽  
Nordin Abu Bakar
Keyword(s):  
Operating System ◽  
Visual Analytics ◽  
Point Clouds ◽  
Accurate Estimation ◽  
Point Cloud Data ◽  
Cloud Data ◽  
Localization And Mapping ◽  
Slam Algorithm ◽  
Map Data ◽  
3D Lidar

This paper presents visual analytics of 3D LiDAR point clouds in robotics operating system. In this study, experiment on Simultaneous Localization and Mapping (SLAM) using point cloud data derived from the Light Detection and Ranging (LiDAR) technology is conducted. We argue that one of the weaknesses of the SLAM algorithm is in the localization process of the landmarks. Existing algorithms such as Grid Mapping and Monte Carlo have limitations in dealing with 3D environment data that have led to less accurate estimation. Therefore, this research proposes the SLAM algorithm based on Real-Time Appearance-Based (RTAB) and makes use of the Red Green Blue (RGB) camera for visualisation. The algorithm was tested by using the map data that was collected and simulated on the Robot Operating System (ROS) in Linux environment. We present the results and demonstrates that the map produced by RTAB is better compared to its counterparts. In addition, the probability for the estimated location is improved which allows for better vehicle maneuverability.

scholarly journals 2-D UAV navigation solution with LIDAR sensor under GPS-denied environment

2021 ◽  
Vol 2120 (1) ◽  
pp. 012026
Author(s):  
J C Ho ◽  
S K Phang ◽  
H K Mun
Keyword(s):  
Processing Speed ◽  
Research Work ◽  
Ground Truth ◽  
Lidar Data ◽  
Loop Closure ◽  
Localization And Mapping ◽  
Graph Optimization ◽  
Aerial Vehicle ◽  
Pose Graph Optimization ◽  
Camera Sensors

Abstract Unmanned aerial vehicle (UAV) is widely used by many industries these days such as militaries, agriculture, and surveillance. However, one of the main challenges of UAV is navigating through an environment where global positioning system (GPS) is being denied. The main purpose of this paper is to find a solution for UAV to be able to navigate in a GPS denied surrounding without affecting the drone flight performance. There are two ways to overcome these challenges such as using visual odometry (VO) or by using simultaneous localization and mapping (SLAM). However, VO has a drawback because camera sensors require good lighting which will affect the performance of the UAV when it is navigating through a low light intensity environment. Hence, in this paper 2-D SLAM will be use as a solution to help UAV to navigate under a GPS-denied environment with the help of a light detection and ranging (LIDAR) sensor which known as a LIDAR-based SLAM. This is because SLAM can help UAVs to localize itself and map the surrounding of the environment. The concept and idea of this paper will be fully simulated using MATLAB, where the drone navigation will be simulated in MATLAB to extract LIDAR data and to use the LIDAR data to carry out SLAM via pose graph optimization. Besides, the contribution to this research work has also identified that in pose graph optimization, the loop closure threshold and loop closure radius play an important role. The loop closure threshold can affect the accuracy of the trajectory of the drone and the accuracy of mapping the environment as compared to ground truth. On the other hand, the loop closure search radius can increase the processing speed of obtaining the data via pose graph optimization. The main contribution to this research work is shown that the processing speed can increase up to 45 % and the accuracy of the trajectory of the drone and the mapped surrounding is quite accurate as compared to ground truth.

scholarly journals Parallel Tracking and Mapping for Controlling VTOL Airframe

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Michal Jama ◽  
Dale Schinstock
Keyword(s):  
Traditional Approach ◽  
Video Stream ◽  
Monocular Vision ◽  
Map Building ◽  
Depth Cameras ◽  
Localization And Mapping ◽  
Monocular Slam ◽  
Aerial Vehicle ◽  
Improved Performance ◽  
Slam Algorithm

This work presents a vision based system for navigation on a vertical takeoff and landing unmanned aerial vehicle (UAV). This is a monocular vision based, simultaneous localization and mapping (SLAM) system, which measures the position and orientation of the camera and builds a map of the environment using a video stream from a single camera. This is different from past SLAM solutions on UAV which use sensors that measure depth, like LIDAR, stereoscopic cameras or depth cameras. Solution presented in this paper extends and significantly modifies a recent open-source algorithm that solves SLAM problem using approach fundamentally different from a traditional approach. Proposed modifications provide the position measurements necessary for the navigation solution on a UAV. The main contributions of this work include: (1) extension of the map building algorithm to enable it to be used realistically while controlling a UAV and simultaneously building the map; (2) improved performance of the SLAM algorithm for lower camera frame rates; and (3) the first known demonstration of a monocular SLAM algorithm successfully controlling a UAV while simultaneously building the map. This work demonstrates that a fully autonomous UAV that uses monocular vision for navigation is feasible.

A Macintosh Interface for the Cameca Camebax-Micro Electron Microprobe

1990 ◽  
Vol 48 (1) ◽  
pp. 438-439
Author(s):  
Carl E. Henderson
Keyword(s):  
Electron Microprobe ◽  
Processing Speed ◽  
Word Processing ◽  
State Of The Art ◽  
Computer Control ◽  
Third Party ◽  
Disk Storage ◽  
The Past ◽  
User Facility ◽  
Instrument Control

Over the past few years it has become apparent in our multi-user facility that the computer system and software supplied in 1985 with our CAMECA CAMEBAX-MICRO electron microprobe analyzer has the greatest potential for improvement and updating of any component of the instrument. While the standard CAMECA software running on a DEC PDP-11/23+ computer under the RSX-11M operating system can perform almost any task required of the instrument, the commands are not always intuitive and can be difficult to remember for the casual user (of which our laboratory has many). Given the widespread and growing use of other microcomputers (such as PC’s and Macintoshes) by users of the microprobe, the PDP has become the “oddball” and has also fallen behind the state-of-the-art in terms of processing speed and disk storage capabilities. Upgrade paths within products available from DEC are considered to be too expensive for the benefits received. After using a Macintosh for other tasks in the laboratory, such as instrument use and billing records, word processing, and graphics display, its unique and “friendly” user interface suggested an easier-to-use system for computer control of the electron microprobe automation. Specifically a Macintosh IIx was chosen for its capacity for third-party add-on cards used in instrument control.

Toward The Simultaneous Correction of Spherical and Chromatic Aberration in Electron Optics by Means of an Electrostatic Electron Mirror

1990 ◽  
Vol 48 (1) ◽  
pp. 206-207
Author(s):  
Gertrude. F. Rempfer
Keyword(s):  
Chromatic Aberration ◽  
Transverse Magnetic ◽  
Objective Lens ◽  
Ion Imaging ◽  
Corrected Image ◽  
Electric And Magnetic Fields ◽  
Chromatic Aberrations ◽  
Improved Performance ◽  
Electron Microscopes ◽  
Image Planes

Optimum performance in electron and ion imaging instruments, such as electron microscopes and probe-forming instruments, in most cases depends on a compromise either between imaging errors due to spherical and chromatic aberrations and the diffraction error or between the imaging errors and the current in the image. These compromises result in the use of very small angular apertures. Reducing the spherical and chromatic aberration coefficients would permit the use of larger apertures with resulting improved performance, granted that other problems such as incorrect operation of the instrument or spurious disturbances do not interfere. One approach to correcting aberrations which has been investigated extensively is through the use of multipole electric and magnetic fields. Another approach involves the use of foil windows. However, a practical system for correcting spherical and chromatic aberration is not yet available.Our approach to correction of spherical and chromatic aberration makes use of an electrostatic electron mirror. Early studies of the properties of electron mirrors were done by Recknagel. More recently my colleagues and I have studied the properties of the hyperbolic electron mirror as a function of the ratio of accelerating voltage to mirror voltage. The spherical and chromatic aberration coefficients of the mirror are of opposite sign (overcorrected) from those of electron lenses (undercorrected). This important property invites one to find a way to incorporate a correcting mirror in an electron microscope. Unfortunately, the parts of the beam heading toward and away from the mirror must be separated. A transverse magnetic field can separate the beams, but in general the deflection aberrations degrade the image. The key to avoiding the detrimental effects of deflection aberrations is to have deflections take place at image planes. Our separating system is shown in Fig. 1. Deflections take place at the separating magnet and also at two additional magnetic deflectors. The uncorrected magnified image formed by the objective lens is focused in the first deflector, and relay lenses transfer the image to the separating magnet. The interface lens and the hyperbolic mirror acting in zoom fashion return the corrected image to the separating magnet, and the second set of relay lenses transfers the image to the final deflector, where the beam is deflected onto the projection axis.

Sign in / Sign up

Export Citation Format

Share Document