scholarly journals Hand-Eye Motion-Invariant Pose Estimation with Online 1-Step GA -3D Pose Tracking Accuracy Evaluation in Dynamic Hand-Eye Oscillation-

2009 ◽  
Vol 21 (6) ◽  
pp. 709-719 ◽  
Author(s):  
Mamoru Minami ◽  
◽  
Wei Song
Keyword(s):  
Accuracy Evaluation ◽  
Evolutionary Search ◽  
Model Matching ◽  
Dynamic Effects ◽  
Tracking Accuracy ◽  
Unit Quaternion ◽  
Fitness Evaluation ◽  
3 Dimensional ◽  
Pose Tracking ◽  
Eye Motion

This paper presents online pose measurement for a 3-dimensional (3-D) object detected by stereo hand-eye cameras. Our proposal improves 3-D pose tracking accuracy by compensating for the fictional motion of the target in camera images stemming from the ego motion of the hand-eye camera caused by dynamic manipulator oscillation. This motion feed-forward (MFF) is combined into the evolutionary search of a genetic algorithm (GA) and fitness evaluation based on stereo model matching whose pose is expressed using a unit quaternion. The proposal’s effectiveness was confirmed in simulation tracking an object’s 3-D pose adversely affected by hand-eye camera oscillations induced by dynamic effects of robot motion.

scholarly journals 3-Dimensional Magnetic Resonance Imaging of the Freely Moving Human Eye

2020 ◽  
Author(s):  
Benedetta Franceschiello ◽  
Lorenzo Di Sopra ◽  
Astrid Minier ◽  
Silvio Ionta ◽  
David Zeugin ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Eye Tracking ◽  
Tracking System ◽  
Patent Application ◽  
Movement Analysis ◽  
Resonance Imaging ◽  
3 Dimensional ◽  
Eye Motion ◽  
Financial Interests

AbstractEye motion is a major confound for magnetic resonance imaging (MRI) in neuroscience or ophthalmology. Currently, solutions toward eye stabilisation include participants fixating or administration of paralytics/anaesthetics. We developed a novel MRI protocol for acquiring 3-dimensional images while the eye freely moves. Eye motion serves as the basis for image reconstruction, rather than an impediment. We fully reconstruct videos of the moving eye and head. We quantitatively validate data quality with millimetre resolution in two ways for individual participants. First, eye position based on reconstructed images correlated with simultaneous eye-tracking. Second, the reconstructed images preserve anatomical properties; the eye’s axial length measured from MRI images matched that obtained with ocular biometry. The technique operates on a standard clinical setup, without necessitating specialized hardware, facilitating wide deployment. In clinical practice, we anticipate that this may help reduce burden on both patients and infrastructure, by integrating multiple varieties of assessments into a single comprehensive session. More generally, our protocol is a harbinger for removing the necessity of fixation, thereby opening new opportunities for ethologically-valid, naturalistic paradigms, the inclusion of populations typically unable to stably fixate, and increased translational research such as in awake animals whose eye movements constitute an accessible behavioural readout.Author contributionsB.F., L.D.S., M.S., and M.M.M. conceptualised the problem. B.F. and L.D.S. developed, implemented, and tested the protocol. A.M. provided optometry assessments and assisted with eye movement analysis. S.I., D.Z., and M.P.N. assisted with installation of the eye-tracking system within the MRI scanner. J.A.M.B., J.J. and J.Y. contributed with the MRI sequences and compressed sensing framework. B.F., L.D.S. and M.M.M. drafted the manuscript, and all authors contributed to internal review.Competing interestsB.F., L.D.S., J.A.M.B., J.Y., M.S., and M.M.M. declare the following competing financial interest: a patent application for the protocol described in this manuscript has been filed (patent application: EP19160832). A.M., S.I., D.Z., M.P.N. and J.J. declare no competing financial interests.

scholarly journals 1/2SH

Stroke ◽  
2020 ◽  
Vol 51 (1) ◽  
pp. 193-201 ◽  
Author(s):  
Biao Zhao ◽  
Wan-bing Jia ◽  
Li-ying Zhang ◽  
Ting-zhong Wang
Keyword(s):  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Operating Characteristic ◽  
Small Volume ◽  
Characteristic Curve ◽  
Intraclass Correlation ◽  
Intracerebral Hematoma ◽  
Accuracy Evaluation ◽  
Imaging Data ◽  
3 Dimensional

Background and Purpose— 1/2ABC has been used widely for assessing the volume of intracerebral hematoma. However, it is only suitable for calculating regular and small volume hematomas. Therefore, we re-explored the formula of hematoma volume to find a method that can calculate hematoma volumes accurately, reliably, and quickly. Methods— Computed tomography imaging data of 257 patients with intracerebral hemorrhage were collected. Hematoma volumes were estimated using 3-dimensional Slicer and 7 formulas (π/6ABC, 1/2ABC, 1/3ABC, 2/3SH, 1/2SH, π/6SH, and 2.5/6ABC). Taking the hematoma volumes measured by 3-dimensional Slicer as the reference standard, the accuracy and reliability of the 7 formulas were evaluated. Furthermore, the time needed to calculate hematoma volumes by the 1/2SH method was noted for further analysis. Results— (1) The accuracy of the 7 formulas based on the error analysis from the highest to the lowest was: π/6SH, 1/2SH, 2.5/6ABC, 1/3ABC, 1/2ABC, and π/6ABC or 2/3SH. According to concordance analysis and receiver operating characteristic curve analysis, the results from the highest to lowest were as follows: 1/2SH, π/6SH, 2.5/6ABC, 1/3ABC, 1/2ABC, 2/3SH, and π/6ABC. After categorizing cases according to size, shape, and location of hematoma, the results were almost the same as the results for overall accuracy evaluation in any subgroup. (2) Intraclass correlation coefficient (ICC) of 1/2SH in intra and inter-researcher were 0.998 and 0.989, respectively. For the formula π/6SH, intraclass correlation coefficient was the same as that of 1/2ABC. Kappa values of 1/2SH for intra- and inter-observer were 0.992 and 0.913, respectively. For π/6SH, kappa values of within- and between-reader were 0.984 and 0.904, respectively. (3) The average time taken to calculate hematoma volumes by 1/2SH was 74 seconds. Conclusions— The 1/2SH and π/6SH are accurate, reliable, and rapid methods for calculating hematoma volumes. The accuracy and reliability of 1/2SH were slightly higher than those of π/6SH.

scholarly journals Towards Tumor Margins Reduction: Tracking Accuracy Evaluation of an MRI-RT System

2017 ◽  
Vol 99 (2) ◽  
pp. S124-S125
Author(s):  
D. Cusumano ◽  
L. Boldrini ◽  
F. Cellini ◽  
S. Teodoli ◽  
N. Dinapoli ◽  
...  
Keyword(s):  
Accuracy Evaluation ◽  
Tracking Accuracy ◽  
Tumor Margins

scholarly journals An automated method for the evaluation of the pointing accuracy of sun-tracking devices

2016 ◽  
Author(s):  
Dietmar J. Baumgartner ◽  
Werner Pötzi ◽  
Heinrich Freislich ◽  
Heinz Strutzmann ◽  
Astrid M. Veronig ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Monitoring System ◽  
Automated System ◽  
Accuracy Evaluation ◽  
Tracking Accuracy ◽  
Clear Sky ◽  
Automated Method ◽  
Pointing Accuracy ◽  
Sky Conditions ◽  
Tracking Devices

Abstract. The accuracy of solar radiation measurements (for direct and diffuse radiation) depends significantly on the precision of the operational sun-tracking device. Thus rigid targets for instrument performance and operation have been specified for international monitoring networks, such as e.g., the Baseline Surface Radiation Network (BSRN) operating under the auspices of the World Climate Research Program (WCRP). Sun-tracking devices fulfilling these accuracy requirements are available from various instrument manufacturers, however none of the commercially available systems comprises an automatic accuracy control system, allowing platform operators to independently validate the pointing accuracy of sun-tracking sensors during operation. Here we present KSO-STREAMS (KSO-SunTRackEr Accuracy Monitoring System), a fully automated, system independent and cost-effective method for evaluating the pointing accuracy of sun-tracking devices. We detail the monitoring system setup, its design and specifications and results from its application to the sun-tracking system operated at the Austrian RADiation network (ARAD) site Kanzelhöhe Observatory (KSO). Results from an evaluation campaign from March to June 2015 show that the tracking accuracy of the device operated at KSO lies for the vast majority of observations (99.8 %) within BSRN specifications (i.e., 0.1° tracking accuracy). Evaluation of manufacturer specified active tracking accuracies (0.02°), during periods with direct solar radiation exceeding 300 W m−2, shows that these are satisfied for 72.9 % of observations. Tracking accuracies are highest during clear-sky conditions and on days where prevailing clear-sky conditions are interrupted by frontal movement: in these cases we obtain complete fulfillment of BSRN requirements and 76.4 % of observations within manufacturer specified active tracking accuracies. Limitations to tracking surveillance arise during overcast conditions and periods of partial solar limb coverage by clouds. On days with variable cloud-cover 78.1 % (99.9 %) of observations meet active tracking (BSRN) accuracy requirements while for days with prevailing overcast conditions these numbers reduce to 64.3 % (99.5 %), respectively.

scholarly journals Tracking Accuracy Evaluation of Electromagnetic Sensor-Based Colonoscope Tracking Method

2016 ◽  
pp. 101-108
Author(s):  
Masahiro Oda ◽  
Hiroaki Kondo ◽  
Takayuki Kitasaka ◽  
Kazuhiro Furukawa ◽  
Ryoji Miyahara ◽  
...  
Keyword(s):  
Accuracy Evaluation ◽  
Tracking Accuracy ◽  
Tracking Method ◽  
Electromagnetic Sensor

scholarly journals Human Teleoperation - A Haptically Enabled Mixed Reality System for Teleultrasound

2021 ◽  
Author(s):  
David Black ◽  
Yas Oloumi Yazdi ◽  
Amir Hossein Hadi Hosseinabadi ◽  
Septimiu Salcudean
Keyword(s):  
Mixed Reality ◽  
Ultrasound Images ◽  
Ultrasound Probe ◽  
3 Dimensional ◽  
Pose Tracking ◽  
Virtual Device ◽  
Control Framework ◽  
Novel Concept ◽  
Robotic Teleoperation

<div> <div> <div> <p>Current teleguidance methods include verbal guidance and robotic teleoperation, which present tradeoffs between precision and latency versus flexibility and cost. We present a novel concept of "human teleoperation" which bridges the gap between these two methods. A prototype teleultrasound system was implemented which shows the concept’s efficacy. An expert remotely "teloperates" a person (the follower) wearing a mixed reality headset by controlling a virtual ultrasound probe projected into the person’s scene. The follower matches the pose and force of the virtual device with a real probe. The pose, force, video, ultrasound images, and 3-dimensional mesh of the scene are fed back to the expert. In this control framework, the input and the actuation are carried out by people, but with near robot-like latency and precision. This allows teleguidance that is more precise and fast than verbal guidance, yet more flexible and inexpensive than robotic teleoperation. The system was subjected to tests that show its effectiveness, including mean teleoperation latencies of 0.27 seconds and errors of 7 mm and 6◦ in pose tracking. The system was also tested with an expert ultrasonographer and four patients and was found to improve the precision and speed of two teleultrasound procedures. </p> </div> </div> </div>

Tracking control of a 3-dimensional piezo-driven micro-positioning system using a dynamic Prandtl–Ishlinskii model

2021 ◽  
pp. 1045389X2110482
Author(s):  
Wei Zhu ◽  
Feifei Liu ◽  
Fufeng Yang ◽  
Xiaoting Rui
Keyword(s):  
Power Amplifier ◽  
Dynamic Characteristics ◽  
Tracking Control ◽  
Feedforward Control ◽  
Positioning System ◽  
Hysteresis Model ◽  
Tracking Accuracy ◽  
Simple Method ◽  
3 Dimensional ◽  
Rate Dependent

A controller composed of a feed-forward loop based on a novel dynamic Prandtl–Ishlinskii (P-I) model and a PID feedback control loop is developed to support a 3-dimensional piezo-driven micro-positioning system for high-bandwidth tracking control. By considering the dynamic characteristics of the power amplifier, the dynamic P-I model can accurately describe the rate-dependent hysteresis of piezoelectric stack actuators (PSAs). To ensure that the hysteresis model is independent of system load, the P-I hysteresis operator in that model characterizes the relationship between the output force and the input voltage of PSAs. The dynamics equation of the mechanical is established by using the cutoff modal method. The feedforward control is designed based on the dynamic hysteresis model to reduce the rate-dependent hysteresis. The PID control is incorporated with the feedforward control to increase the tracking accuracy. Experimental results indicate that the controller can overcome the hysteresis efficiently and preserve good positioning accuracy in 1–100 Hz bandwidth. Just by introducing the dynamic characteristics of the power amplifier, which can be expressed as a first-order differential equation, the P-I model can accurately describe the rate-dependent hysteresis of the PSA, which provides a simple method to describe and control piezoelectric actuators and piezo-driven systems in a wide frequency.

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