scholarly journals Contributions of pictorial and binocular cues to the perception of distance in virtual reality

2021 ◽  
Author(s):  
Rebecca L. Hornsey ◽  
Paul B. Hibbard
Keyword(s):  
Virtual Reality ◽  
Distance Perception ◽  
Linear Perspective ◽  
Reference Stimulus ◽  
Systematic Bias ◽  
Indoor Environments ◽  
Accuracy And Precision ◽  
Pictorial Cues ◽  
Systematic Biases ◽  
Nonlinear Compression

AbstractWe assessed the contribution of binocular disparity and the pictorial cues of linear perspective, texture, and scene clutter to the perception of distance in consumer virtual reality. As additional cues are made available, distance perception is predicted to improve, as measured by a reduction in systematic bias, and an increase in precision. We assessed (1) whether space is nonlinearly distorted; (2) the degree of size constancy across changes in distance; and (3) the weighting of pictorial versus binocular cues in VR. In the first task, participants positioned two spheres so as to divide the egocentric distance to a reference stimulus (presented between 3 and 11 m) into three equal thirds. In the second and third tasks, participants set the size of a sphere, presented at the same distances and at eye-height, to match that of a hand-held football. Each task was performed in four environments varying in the available cues. We measured accuracy by identifying systematic biases in responses and precision as the standard deviation of these responses. While there was no evidence of nonlinear compression of space, participants did tend to underestimate distance linearly, but this bias was reduced with the addition of each cue. The addition of binocular cues, when rich pictorial cues were already available, reduced both the bias and variability of estimates. These results show that linear perspective and binocular cues, in particular, improve the accuracy and precision of distance estimates in virtual reality across a range of distances typical of many indoor environments.

Estimating Distances in Action Space in Augmented Reality

2021 ◽  
Vol 18 (2) ◽  
pp. 1-16
Author(s):  
Holly C. Gagnon ◽  
Carlos Salas Rosales ◽  
Ryan Mileris ◽  
Jeanine K. Stefanucci ◽  
Sarah H. Creem-Regehr ◽  
...  
Keyword(s):  
Augmented Reality ◽  
Real World ◽  
Distance Measure ◽  
Distance Perception ◽  
Action Space ◽  
Indoor Environments ◽  
Verbal Reports ◽  
Visual Matching ◽  
Microsoft Hololens ◽  
Real Person

Augmented reality ( AR ) is important for training complex tasks, such as navigation, assembly, and medical procedures. The effectiveness of such training may depend on accurate spatial localization of AR objects in the environment. This article presents two experiments that test egocentric distance perception in augmented reality within and at the boundaries of action space (up to 35 m) in comparison with distance perception in a matched real-world ( RW ) environment. Using the Microsoft HoloLens, in Experiment 1, participants in two different RW settings judged egocentric distances (ranging from 10 to 35 m) to an AR avatar or a real person using a visual matching measure. Distances to augmented targets were underestimated compared to real targets in the two indoor, RW contexts. Experiment 2 aimed to generalize the results to an absolute distance measure using verbal reports in one of the indoor environments. Similar to Experiment 1, distances to augmented targets were underestimated compared to real targets. We discuss these findings with respect to the importance of methodologies that directly compare performance in real and mediated environments, as well as the inherent differences present in mediated environments that are “matched” to the real world.

scholarly journals INTERACTIVE VISUALIZATION TECHNOLOGY IN AUGMENTED REALITY

2021 ◽  
Vol 58 (3) ◽  
pp. 137-142
Author(s):  
A.O. Dauitbayeva ◽  
◽  
A.A. Myrzamuratova ◽  
A.B. Bexeitova ◽  
◽  
...  
Keyword(s):  
Virtual Reality ◽  
Augmented Reality ◽  
User Interfaces ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Linear Perspective ◽  
Three Dimensional Objects ◽  
Visualization Technology ◽  
Image Volume ◽  
Dimensional Object

This article is devoted to the issues of visualization and information processing, in particular, improving the visualization of three-dimensional objects using augmented reality and virtual reality technologies. The globalization of virtual reality has led to the introduction of a new term "augmented reality"into scientific circulation. If the current technologies of user interfaces are focused mainly on the interaction of a person and a computer, then augmented reality with the help of computer technologies offers improving the interface of a person and the real world around them. Computer graphics are perceived by the system in the synthesized image in connection with the reproduction of monocular observation conditions, increasing the image volume, spatial arrangement of objects in a linear perspective, obstructing one object to another, changing the nature of shadows and tones in the image field. The experience of observation is of great importance for the perception of volume and space, so that the user "completes" the volume structure of the observed representation. Thus, the visualization offered by augmented reality in a real environment familiar to the user contributes to a better perception of three-dimensional object.

Teleseismic slowness-azimuth station corrections for the International Monitoring System Seismic Network

1999 ◽  
Vol 89 (4) ◽  
pp. 989-1003 ◽  
Author(s):  
István Bondár ◽  
Robert G. North ◽  
Gregory Beall
Keyword(s):  
Monitoring System ◽  
Global Network ◽  
Systematic Bias ◽  
International Monitoring System ◽  
Time Data ◽  
International Monitoring ◽  
Event Location ◽  
Systematic Biases ◽  
Predicted Values ◽  
Test Ban

Abstract The prototype International Data Center (PIDC) in Arlington, Virginia, has been developing and testing software and procedures for use in the verification of the Comprehensive Test Ban Treaty. After three years of operation with a global network of array and three-component stations, it has been possible to characterize various systematic biases of those stations that are designated in the Treaty as part of the International Monitoring System (IMS). These biases include deviations of azimuth and slowness measurements from predicted values, caused largely by lateral heterogeneity. For events recorded by few stations, azimuth and slowness are used in addition to arrival-time data for location by the PIDC. Corrections to teleseismic azimuth and slowness observations have been empirically determined for most IMS stations providing data to the PIDC. Application of these corrections is shown to improve signal association and event location. At some stations an overall systematic bias can be ascribed to local crustal structure or to unreported instrumental problems. The corrections have been applied in routine operation of the PIDC since February 1998.

scholarly journals Identification and utilization of copy number information for correcting Hi-C contact map of cancer cell lines

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Ahmed Ibrahim Samir Khalil ◽  
Siti Rawaidah Binte Mohammad Muzaki ◽  
Anupam Chattopadhyay ◽  
Amartya Sanyal
Keyword(s):  
Cell Lines ◽  
Cancer Cell ◽  
Copy Number ◽  
Cancer Cell Lines ◽  
Chromatin Interaction ◽  
Systematic Bias ◽  
Contact Map ◽  
Dna Copy Number ◽  
Contact Maps ◽  
Systematic Biases

Abstract Background Hi-C and its variant techniques have been developed to capture the spatial organization of chromatin. Normalization of Hi-C contact map is essential for accurate modeling and interpretation of high-throughput chromatin conformation capture (3C) experiments. Hi-C correction tools were originally developed to normalize systematic biases of karyotypically normal cell lines. However, a vast majority of available Hi-C datasets are derived from cancer cell lines that carry multi-level DNA copy number variations (CNVs). CNV regions display over- or under-representation of interaction frequencies compared to CN-neutral regions. Therefore, it is necessary to remove CNV-driven bias from chromatin interaction data of cancer cell lines to generate a euploid-equivalent contact map. Results We developed the HiCNAtra framework to compute high-resolution CNV profiles from Hi-C or 3C-seq data of cancer cell lines and to correct chromatin contact maps from systematic biases including CNV-associated bias. First, we introduce a novel ‘entire-fragment’ counting method for better estimation of the read depth (RD) signal from Hi-C reads that recapitulates the whole-genome sequencing (WGS)-derived coverage signal. Second, HiCNAtra employs a multimodal-based hierarchical CNV calling approach, which outperformed OneD and HiNT tools, to accurately identify CNVs of cancer cell lines. Third, incorporating CNV information with other systematic biases, HiCNAtra simultaneously estimates the contribution of each bias and explicitly corrects the interaction matrix using Poisson regression. HiCNAtra normalization abolishes CNV-induced artifacts from the contact map generating a heatmap with homogeneous signal. When benchmarked against OneD, CAIC, and ICE methods using MCF7 cancer cell line, HiCNAtra-corrected heatmap achieves the least 1D signal variation without deforming the inherent chromatin interaction signal. Additionally, HiCNAtra-corrected contact frequencies have minimum correlations with each of the systematic bias sources compared to OneD’s explicit method. Visual inspection of CNV profiles and contact maps of cancer cell lines reveals that HiCNAtra is the most robust Hi-C correction tool for ameliorating CNV-induced bias. Conclusions HiCNAtra is a Hi-C-based computational tool that provides an analytical and visualization framework for DNA copy number profiling and chromatin contact map correction of karyotypically abnormal cell lines. HiCNAtra is an open-source software implemented in MATLAB and is available at https://github.com/AISKhalil/HiCNAtra.

scholarly journals The Accuracy and Precision of Position and Orientation Tracking in the HTC Vive Virtual Reality System for Scientific Research

i-Perception ◽  
2017 ◽  
Vol 8 (3) ◽  
pp. 204166951770820 ◽  
Author(s):  
Diederick C. Niehorster ◽  
Li Li ◽  
Markus Lappe
Keyword(s):  
Virtual Reality ◽  
Visual Stimulation ◽  
Tracking System ◽  
Ground Plane ◽  
Calibration Procedure ◽  
Large Field ◽  
Head Mounted Display ◽  
Accuracy And Precision ◽  
Time Calibration ◽  
Position And Orientation

The advent of inexpensive consumer virtual reality equipment enables many more researchers to study perception with naturally moving observers. One such system, the HTC Vive, offers a large field-of-view, high-resolution head mounted display together with a room-scale tracking system for less than a thousand U.S. dollars. If the position and orientation tracking of this system is of sufficient accuracy and precision, it could be suitable for much research that is currently done with far more expensive systems. Here we present a quantitative test of the HTC Vive’s position and orientation tracking as well as its end-to-end system latency. We report that while the precision of the Vive’s tracking measurements is high and its system latency (22 ms) is low, its position and orientation measurements are provided in a coordinate system that is tilted with respect to the physical ground plane. Because large changes in offset were found whenever tracking was briefly lost, it cannot be corrected for with a one-time calibration procedure. We conclude that the varying offset between the virtual and the physical tracking space makes the HTC Vive at present unsuitable for scientific experiments that require accurate visual stimulation of self-motion through a virtual world. It may however be suited for other experiments that do not have this requirement.

An error in brightness matching associated with the application of dimming

2001 ◽  
Vol 33 (4) ◽  
pp. 223-229 ◽  
Author(s):  
Steve A Fotios
Keyword(s):  
Experimental Design ◽  
Paired Comparison ◽  
Reference Stimulus ◽  
Systematic Bias ◽  
Null Condition

This paper discusses requirements for good experimental design in brightness matching tests. Experimental and null-condition data from paired-comparison brightness matching shows a systematic bias; a tendency for the stimulus to which observers apply dimming to be set to an illuminance below that of the reference stimulus. The error is small but statistically significant.

scholarly journals Simulating systematic bias in attributed social networks and its effect on rankings of minority nodes

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Leonie Neuhäuser ◽  
Felix I. Stamm ◽  
Florian Lemmerich ◽  
Michael T. Schaub ◽  
Markus Strohmaier
Keyword(s):  
Network Analysis ◽  
Measurement Errors ◽  
Social Systems ◽  
Systematic Bias ◽  
Model Framework ◽  
Network Analyses ◽  
External Node ◽  
Systematic Biases ◽  
Node Attributes ◽  
Attributed Networks

AbstractNetwork analysis provides powerful tools to learn about a variety of social systems. However, most analyses implicitly assume that the considered relational data is error-free, and reliable and accurately reflects the system to be analysed. Especially if the network consists of multiple groups (e.g., genders, races), this assumption conflicts with a range of systematic biases, measurement errors and other inaccuracies that are well documented in the literature. To investigate the effects of such errors we introduce a framework for simulating systematic bias in attributed networks. Our framework enables us to model erroneous edge observations that are driven by external node attributes or errors arising from the (hidden) network structure itself. We exemplify how systematic inaccuracies distort conclusions drawn from network analyses on the task of minority representations in degree-based rankings. By analysing synthetic and real networks with varying homophily levels and group sizes, we find that the effect of introducing systematic edge errors depends on both the type of edge error and the level of homophily in the system: in heterophilic networks, minority representations in rankings are very sensitive to the type of systematic edge error. In contrast, in homophilic networks we find that minorities are at a disadvantage regardless of the type of error present. We thus conclude that the implications of systematic bias in edge data depend on an interplay between network topology and type of systematic error. This emphasises the need for an error model framework as developed here, which provides a first step towards studying the effects of systematic edge-uncertainty for various network analysis tasks.

scholarly journals How much do standard area diagrams improve accuracy of visual estimates of plant disease severity? A systematic review and meta-analysis

2021 ◽  
Author(s):  
Emerson Medeiros Del Ponte ◽  
Luis Ignacio Cazón ◽  
Kaique Santos Alves ◽  
Sarah J. Pethybridge ◽  
Clive H. Bock
Keyword(s):  
Systematic Review ◽  
Disease Severity ◽  
Plant Disease ◽  
Multiple Correspondence Analysis ◽  
Meta Analysis ◽  
Systematic Bias ◽  
Constant Bias ◽  
Systematic Biases ◽  
Visual Assessments ◽  
Selection Of

Plant disease severity is commonly estimated visually without or with the aid of standard area diagram sets (SADs). It is generally believed that the use of SADs leads to less biased (more accurate) and thus more precise estimates, but the degree of improvement has not been characterized in a systematic manner. We built on a previous review and screened 153 SAD studies published from 1990 to 2021. A systematic review resulted in a selection of 72 studies that reported three linear regression statistics for individual raters, which are indicative of the two components of bias (intercept = constant bias; slope = systematic bias) and precision (Pearson's correlation coefficient, r), to perform a meta-analysis of these accuracy components. The meta-analytic model determined an overall gain of 0.07 (r increased from 0.88 to 0.95) in precision. Globally, there was a reduction of 2.65 units in the intercept, from 3.41 to 0.76, indicating a reduction in the constant bias. Slope was least affected and was reduced slightly from 1.09 to 0.966, indicating marginally less systematic bias when using SADs. A multiple correspondence analysis suggested an association of less accurate, unaided estimates with diseases that produce numerous lesions and for which maximum severities of 50% are rarely attained. On the other hand, more accurate estimates were observed with diseases that cause only a few lesions and those diseases where the lesions coalesce and occupy more than 50% of the specimen surface. This was most pronounced for specimen types other than leaves. By quantitatively exploring how characteristics of the pathosystem and how SADs affect precision and constant and systematic biases, we affirm the value of SADs for reducing bias and imprecision of visual assessments. We have also identified situations where SADs have greater or lesser effects as an assessment aid.

scholarly journals Interaksi 3D Sensor Leap Motion untuk Menggenggam Benda Virtual

CYCLOTRON ◽  
2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Lukman Hakim ◽  
Surya Sumpeno ◽  
Supeno Mardi Susiki Nugroho
Keyword(s):  
Virtual Reality ◽  
Hand Movement ◽  
Fine Motor ◽  
Motion Sensor ◽  
Motion Sensors ◽  
Leap Motion ◽  
3D Interaction ◽  
Virtual Objects ◽  
Accuracy And Precision ◽  
Fine Motor Performance

Abstrak - Penelitian ini membahas tentang interaksi 3D sensor Leap Motion untuk simulasi menggenggam Benda virtual Plastis. Sebuah interaksi 3D sensor Leap Motion yang digunakan sebagai simulasi untuk menggenggam benda virtual Plastis dengan menggunakan media objek telur virtual secara presisi dan akurasi yang tepat. Pada dasarnya menggenggam merupakan suatu kegiatan yang menerapkan kinerja motorik halus pada tangan untuk melakukan gerakan. Penggunaan sensor Leap Motion sebagai interaksi 3D dipakai untuk menggenggam objek maya dalam hal ini bentuk 3D telur virtual sebagai media praktiknya. Telur sendiri merupakan benda yang gampang distimulasi dan memiliki sifat texture yang halus untuk merespon segala bentuk gerakan pada genggaman tangan. Dalam penelitian Interaksi 3D Sensor Leap Motion untuk simulasi untuk menggenggam benda Virtual Plastis dengan menggunakan media objek telur virtual, ini di peruntukkan untuk mengetahui akurasi dan presisi dari pola gerakan tangan secara imersif. Pengembangan dari metode ini bertujuan untuk simulasi menggenggam benda atau objek maya dengan adanya interaksi pola gerakan tangan.Kata kunci: leapmotion, 3d, virtual reality, benda, telurAbstract - This study discusses about the 3D interaction of the Leap Motion sensor for the simulation of holding virtual plastic objects. A 3D interaction of the Leap Motion sensor that is used as a simulation to hold Plastis virtual objects by using virtual egg object media with precise and right accuracy. Basically, holding is an activity that applies fine motor performance on the hands to make movements. The use of the Leap Motion sensor as a 3D interaction is used to hold virtual objects in this case a 3D form of virtual eggs as practice media. Eggs are objects that are easily stimulated and have subtle texture to respond to all forms of movement in the hands. In the 3D interaction Leap Motion Sensors for virtual plastic objects holding simulation by using virtual egg object media, it is intended to find out the accuracy and precision of immersive hand movement patterns. The development of this method aims to simulate holding virtual objects or objects with the interaction of hand movement patterns.Keywords: leap motion, 3d, virtual reality, object, egg

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