Evaluation of reconstructed angular error of a continuous rotating HWP for LiteBIRD

2020 ◽  
Author(s):  
Shinya Sugiyama ◽  
Tomotake Matsumura ◽  
Yuki Sakurai ◽  
Nobuhiko Katayama ◽  
Satoru Takakura ◽  
...  
Keyword(s):  
Angular Error

scholarly journals Uncertainty visualization of gaze estimation to support operator-controlled calibration

2018 ◽  
Vol 10 (5) ◽  
Author(s):  
Almoctar Hassoumi ◽  
Vsevolod Peysakhovich ◽  
Christophe Hurter
Keyword(s):  
Qualitative Evaluation ◽  
Point Of View ◽  
Angular Error ◽  
Qualitative Assessment ◽  
Gaze Estimation ◽  
Uncertainty Visualization ◽  
Estimation Uncertainty ◽  
The Mean ◽  
Gaze Position ◽  
Do So

      In this paper, we investigate how visualization assets can support the qualitative evaluation of gaze estimation uncertainty. Although eye tracking data are commonly available, little has been done to visually investigate the uncertainty of recorded gaze information. This paper tries to fill this gap by using innovative uncertainty computation and visualization. Given a gaze processing pipeline, we estimate the location of this gaze position in the world camera. To do so we developed our own gaze data processing which give us access to every stage of the data transformation and thus the uncertainty computation. To validate our gaze estimation pipeline, we designed an experiment with 12 participants and showed that the correction methods we proposed reduced the Mean Angular Error by about 1.32 cm, aggregating all 12 participants’ results. The Mean Angular Error is 0.25° (SD=0.15°) after correction of the estimated gaze. Next, to support the qualitative assessment of this data, we provide a map which codes the actual uncertainty in the user point of view. 

scholarly journals Improving Angular Accuracy of a Scanning Mirror Based on Error Modeling and Correction

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 367 ◽  
Author(s):  
Yue Fan ◽  
Wenli Ma ◽  
Ping Jiang ◽  
Jinlong Huang ◽  
Kewei Chen ◽  
...  
Keyword(s):  
Eddy Current ◽  
Correction Method ◽  
Calculation Model ◽  
Error Model ◽  
Error Modeling ◽  
Angular Error ◽  
Displacement Sensor ◽  
Physical Parameters ◽  
Loop Control ◽  
Scanning Mirror

Scanning mirrors appear to be key components in optoelectronic systems for line-of-sight (LOS) stabilization. For improving the angular accuracy of a scanning mirror based on the eddy current displacement sensor measurement, an angular error-correction method is proposed and demonstrated. A mathematic angular error model with physical parameters was developed, and the cross-validation method was employed to determine the reasonable order of the Maclaurin series used in the error model, which increased the exactitude and robustness of the correction method. The error parameters were identified by accurately fitting the calibrated angular errors with the error model, which showed excellent error prediction performance. Based on the angular calculation model corrected by the error model, the closed-loop control system was established to obtain accurate deflection angles. Experimental results show that within the deflection angle of ±1.5 deg, the angular accuracy was improved from 0.28 deg to less than 1.1 arcsec, and the standard deviation for six measurements was less than 1.2 arcsec, which indicates that the angle correction method was effective in improving the linearity of the eddy current sensors and reducing the influence of manufacturing and installation errors.

scholarly journals Performance Analysis of a Lower Limb Multi Joint Angle Sensor Using CYTOP Fiber: Influence of Light Source Wavelength and Angular Velocity Compensation

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 326 ◽  
Author(s):  
Letícia Avellar ◽  
Arnaldo Leal-Junior ◽  
Carlos Marques ◽  
Anselmo Frizera
Keyword(s):  
Angular Velocity ◽  
Light Source ◽  
Intensity Variation ◽  
Maximum Error ◽  
Angular Error ◽  
Polymer Optical Fiber ◽  
Angle Sensor ◽  
Sensor Performance ◽  
Angular Velocities ◽  
Curvature Sensor

This paper presents the analysis of an intensity variation polymer optical fiber (POF)-based angle sensor performance, i.e., sensitivity, hysteresis and determination coefficient ( R 2 ), using cyclic transparent optical polymer (CYTOP) fiber. The analysis consisted of two approaches: influence of different light source central wavelengths (430 nm, 530 nm, 660 nm, 870 nm and 950 nm) and influence of different angular velocities ( 0.70 rad/s, 0.87 rad/s, 1.16 rad/s, 1.75 rad/s and 3.49 rad/s). The first approach aimed to select the source which resulted in the most suitable performance regarding highest sensitivity and linearity while maintaining lowest hysteresis, through the figure of merit. Thereafter, the analysis of different angular velocities was performed to evaluate the influence of velocity in the curvature sensor performance. Then, a discrete angular velocity compensation was proposed in order to reduce the root-mean-square error (RMSE) of responses for different angular velocities. Ten tests for each analysis were performed with angular range of 0 ∘ to 50 ∘ , based on knee and ankle angle range during the gait. The curvature sensor was applied in patterns simulating the knee and ankle during the gait. Results show repeatability and the best sensor performance for λ = 950 nm in the first analysis and show high errors for high angular velocities ( w = 3.49 rad/s) in the second analysis, which presented up to 50 % angular error. The uncompensated RMSE was high for all velocities ( 6.45 ∘ to 12.41 ∘ ), whereas the compensated RMSE decreased up to 74 % ( 1.67 ∘ to 3.62 ∘ ). The compensated responses of application tests showed maximum error of 5.52 ∘ and minimum of 1.06 ∘ , presenting a decrease of mean angular error up to 30 ∘ when compared with uncompensated responses.

A three-axis autocollimator for detection of angular error motions of a precision stage

CIRP Annals ◽  
2011 ◽  
Vol 60 (1) ◽  
pp. 515-518 ◽  
Author(s):  
W. Gao ◽  
Y. Saito ◽  
H. Muto ◽  
Y. Arai ◽  
Y. Shimizu
Keyword(s):  
Angular Error ◽  
Precision Stage

Accuracy analysis and optimization of an extendible support structure with joint clearances

2020 ◽  
pp. 095440622097305
Author(s):  
Jianzhong Ding ◽  
Chunjie Wang
Keyword(s):  
Monte Carlo ◽  
Reduction Method ◽  
Global Sensitivity Analysis ◽  
Angular Error ◽  
Joint Clearance ◽  
Design Parameters ◽  
Support Structure ◽  
Quasi Monte Carlo ◽  
Joint Clearances ◽  
Independent Parameters

An extendible support structure (ESS) used for unfolding and supporting the antenna array of the Synthetic Aperture Radar (SAR) satellite is reviewed and modeled in this paper. The structure is parameterized by calibrating 12 independent parameters, and following which, angular accuracy of the ESS with joint clearances is modeled. The maximum angular error is obtained by the particle swarm optimization (PSO) and validated by the Monte Carlo simulation. A novel error reduction method is then proposed to improve the accuracy of the structure. In the proposed method, the uncertainty of the joint clearance is eliminated using force constraints by adding small torsional springs. Various joint clearance models with force constraints are proposed to obtain the optimal spring allocation, and based on which, the angular error is further reduced by optimizing the structure of the ESS. The Quasi-Monte-Carlo-based Sobol method for global sensitivity analysis is used to select the design parameters for optimization. Finally, the angular error is greatly reduced.

scholarly journals Analysis of the synchronization error measurement via non-collinear cross-correlation

2015 ◽  
Vol 33 (3) ◽  
pp. 355-359 ◽  
Author(s):  
J. Mu ◽  
X. Wang ◽  
F. Jing ◽  
Q.H. Zhu ◽  
J.Q. Su ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Plasma Parameter ◽  
Incident Angle ◽  
Synchronization Error ◽  
Angular Error ◽  
Error Measurement ◽  
Short Pulses ◽  
Beam Combination ◽  
And Control ◽  
Measurement And Control

AbstractThe method for measuring synchronization error of ultra-short pulses was introduced based on the principle of non-collinear cross-correlation. The analytical expression for the measurement was deduced according to the cross-correlation signal. The influences of angular error on the measurement were analyzed by simulated experiments. The incident angle and the angular error tolerance were both required to be considered and determined for the synchronization error measurement of ultra-short pulses. The results provide a theoretical basis for the measurement and control of the synchronization error in the coherent beam combination, plasma parameter diagnosis, etc.

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