Investigation into the Weight Update Rate for Scan-On-Receive Beamforming

2020 ◽  
Author(s):  
Felipe Queiroz de Almeida ◽  
Marwan Younis ◽  
Gerhard Krieger ◽  
Scott Hensley ◽  
Alberto Moreira
Keyword(s):  
Update Rate

scholarly journals An Improved Localization Method for the Transition between Autonomous Underwater Vehicle Homing and Docking

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2468
Author(s):  
Ri Lin ◽  
Feng Zhang ◽  
Dejun Li ◽  
Mingwei Lin ◽  
Gengli Zhou ◽  
...  
Keyword(s):  
Data Exchange ◽  
Autonomous Underwater Vehicle ◽  
Autonomous Underwater Vehicles ◽  
Optimization Method ◽  
Short Baseline ◽  
Localization Accuracy ◽  
Localization Method ◽  
Mapping Algorithm ◽  
Localization And Mapping ◽  
Update Rate

Docking technology for autonomous underwater vehicles (AUVs) involves energy supply, data exchange and navigation, and plays an important role to extend the endurance of the AUVs. The navigation method used in the transition between AUV homing and docking influences subsequent tasks. How to improve the accuracy of the navigation in this stage is important. However, when using ultra-short baseline (USBL), outliers and slow localization updating rates could possibly cause localization errors. Optical navigation methods using underwater lights and cameras are easily affected by the ambient light. All these may reduce the rate of successful docking. In this paper, research on an improved localization method based on multi-sensor information fusion is carried out. To improve the localization performance of AUVs under motion mutation and light variation conditions, an improved underwater simultaneous localization and mapping algorithm based on ORB features (IU-ORBSALM) is proposed. A nonlinear optimization method is proposed to optimize the scale of monocular visual odometry in IU-ORBSLAM and the AUV pose. Localization tests and five docking missions are executed in a swimming pool. The localization results indicate that the localization accuracy and update rate are both improved. The 100% successful docking rate achieved verifies the feasibility of the proposed localization method.

Presence in virtual environments as a function of type of input device and display update rate

Displays ◽  
1998 ◽  
Vol 19 (2) ◽  
pp. 91-98 ◽  
Author(s):  
Woodrow Barfield ◽  
Kevin M Baird ◽  
Ove J Bjorneseth
Keyword(s):  
Virtual Environments ◽  
Input Device ◽  
Update Rate

scholarly journals Markerless 3D Interaction in an Unconstrained Handheld Mixed Reality Setup

2015 ◽  
Vol 15 (1) ◽  
pp. 25-34 ◽  
Author(s):  
Daniel Fritz ◽  
Annette Mossel ◽  
Hannes Kaufmann
Keyword(s):  
Mixed Reality ◽  
Recognition Rate ◽  
Hand Posture ◽  
3D Interaction ◽  
Handheld Device ◽  
Advantages And Disadvantages ◽  
Depth Data ◽  
Environmental Properties ◽  
Update Rate ◽  
Interaction Task

In mobile applications, it is crucial to provide intuitive means for 2D and 3D interaction. A large number of techniques exist to support a natural user interface (NUI) by detecting the user's hand posture in RGB+D (depth) data. Depending on the given interaction scenario and its environmental properties, each technique has its advantages and disadvantages regarding accuracy and the robustness of posture detection. While the interaction environment in a desktop setup can be constrained to meet certain requirements, a handheld scenario has to deal with varying environmental conditions. To evaluate the performance of techniques on a mobile device, a powerful software framework was developed that is capable of processing and fusing RGB and depth data directly on a handheld device. Using this framework, five existing hand posture recognition techniques were integrated and systematically evaluated by comparing their accuracy under varying illumination and background. Overall results reveal best recognition rate of posture detection for combined RGB+D data at the expense of update rate. To support users in choosing the appropriate technique for their specific mobile interaction task, we derived guidelines based on our study. In the last step, an experimental study was conducted using the detected hand postures to perform the canonical 3D interaction tasks selection and positioning in a mixed reality handheld setup.

scholarly journals Fuzzy Control and Connected Region Marking Algorithm-Based SEM Nanomanipulation

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
Dongjie Li ◽  
Weibin Rong ◽  
Lining Sun ◽  
Bo You ◽  
Yu Zou ◽  
...  
Keyword(s):  
Fuzzy Control ◽  
Control Algorithm ◽  
Force Feedback ◽  
Connected Region ◽  
Feedback Information ◽  
Sem Image ◽  
Position Data ◽  
Update Rate ◽  
Fuzzy Control Algorithm ◽  
Slave Mode

The interactive nanomanipulation platform is established based on fuzzy control and connected region marking (CRM) algorithm in SEM. The 3D virtual nanomanipulation model is developed to make up the insufficiency of the 2D SEM image information, which provides the operator with depth and real-time visual feedback information to guide the manipulation. The haptic device Omega3 is used as the master to control the 3D motion of the nanopositioner in master-slave mode and offer the force sensing to the operator controlled with fuzzy control algorithm. Aiming at sensing of force feedback during the nanomanipulation, the collision detection method of the virtual nanomanipulation model and the force rending model are studied to realize the force feedback of nanomanipulation. The CRM algorithm is introduced to process the SEM image which provides effective position data of the objects for updating the virtual environment (VE), and relevant issues such as calibration and update rate of VE are also discussed. Finally, the performance of the platform is validated by the ZnO nanowire manipulation experiments.

scholarly journals Easily-Deployable Acoustic Local Positioning System Based on Auto-Calibrated Wireless Beacons

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1385 ◽  
Author(s):  
José Moreno ◽  
Fernando Álvarez ◽  
Teodoro Aguilera ◽  
José Paredes
Keyword(s):  
Spread Spectrum ◽  
Low Cost ◽  
Experimental Tests ◽  
Real Time System ◽  
Positioning Systems ◽  
Local Positioning System ◽  
Update Rate ◽  
Positioning Algorithm ◽  
Node Position

Self-calibrated Acoustic Local Positioning Systems (ALPS) generally require a high consumption of hardware and software resources to obtain the user’s position at an acceptable update rate. To address this limitation, this work proposes a self-calibrated ALPS based on a software/hardware co-design approach. This working architecture allows for efficient communications, signal processing tasks, and the running of the positioning algorithm on low-cost devices. This fact also enables the real-time system operation. The proposed system is composed of a minimum of four RF-synchronized active acoustic beacons, which emit spread-spectrum modulated signals to position an unlimited number of receiver nodes. Each receiver node estimates the beacons’ position by means of an auto-calibration process and then computes its own position by means of a 3D multilateration algorithm. A set of experimental tests has been carried out where the feasibility of the proposed system is demonstrated. In these experiments, accuracies below 0.1 m are obtained in the determination of the receptor node position with respect to the set of previously-calibrated beacons.

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