Ocular pursuit and the estimation of time-to-contact with accelerating objects in prediction motion are controlled independently based on first-order estimates

2009 ◽  
Vol 202 (2) ◽  
pp. 327-339 ◽  
Author(s):  
Nicolas Benguigui ◽  
Simon J. Bennett
Keyword(s):  
Time To Contact ◽  
Ocular Pursuit ◽  
First Order ◽  
Prediction Motion ◽  
Estimation Of Time

Eye movements influence estimation of time-to-contact in prediction motion

2010 ◽  
Vol 206 (4) ◽  
pp. 399-407 ◽  
Author(s):  
Simon J. Bennett ◽  
Robin Baures ◽  
Heiko Hecht ◽  
Nicolas Benguigui
Keyword(s):  
Eye Movements ◽  
Time To Contact ◽  
Prediction Motion ◽  
Estimation Of Time

Global and Local Contributions to the Optical Specification of Time to Contact: Observer Sensitivity to Composite Tau

Perception ◽  
10.1068/p3230 ◽  
2002 ◽  
Vol 31 (8) ◽  
pp. 901-924 ◽  
Author(s):  
Reinoud J Bootsma ◽  
Cathy M Craig
Keyword(s):  
Discrimination Performance ◽  
Forced Choice ◽  
Object Motion ◽  
Time To Contact ◽  
Local Expansion ◽  
First Order ◽  
Optical Distance ◽  
Observer Motion ◽  
Environmental Element ◽  
Global And Local

First-order time remaining until a moving observer will pass an environmental element is optically specified in two different ways. The specification provided by global tau (based on the pattern of change of angular bearing) requires that the element is stationary and that the direction of motion is accurately detected, whereas the specification provided by composite tau (based on the patterns of change of optical size and optical distance) does not require either of these. We obtained converging evidence for our hypothesis that observers are sensitive to composite tau in four experiments involving relative judgments of time to passage with forced-choice methodology. Discrimination performance was enhanced in the presence of a local expansion component, while being unaffected when the detection of the direction of heading was impaired. Observers relied on the information carried in composite tau rather than on the information carried in its constituent components. Finally, performance was similar under conditions of observer motion and conditions of object motion. Because composite tau specifies first-order time remaining for a large number of situations, the different ways in which it may be detected are discussed.

scholarly journals Estimation of ma(1) model based on rounded data

2012 ◽  
Vol 51 (1) ◽  
pp. 45-53
Author(s):  
Meihui Guo ◽  
Gen-Liang Li
Keyword(s):  
Maximum Likelihood ◽  
Moving Average ◽  
Decimal Place ◽  
Maximum Likelihood Estimates ◽  
Time Series Models ◽  
Rounding Errors ◽  
First Order ◽  
Rounded Data ◽  
Recorded Data ◽  
Estimation Of Time

ABSTRACT Most recorded data of continuous distributions are rounded to the nearest decimal place due to the precision of the recording mechanism. This rounding entails errors in estimation and measurement. In this study, we consider parameter estimation of time series models based on rounded data. The adjusted maximum likelihood estimates in [Stam, A.-Cogger, K. O.: Rounding errors in autoregressive processes, Internat. J. Forecast. 9 (1993), 487-508] are derived theoretically for the first order moving average MA(1) model. Simulations are performed to compare the efficiencies of the adjusted maximum likelihood estimators with other estimators.

Estimation of Time-to-Contact from Retinal Flow

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 169-169
Author(s):  
M G Harris
Keyword(s):  
Prior Knowledge ◽  
Human Performance ◽  
Rotational Component ◽  
Time To Contact ◽  
Focus Of Expansion ◽  
The World ◽  
New Models ◽  
Smooth Planes ◽  
Estimation Of Time ◽  
Rotation Component

We investigated four models for estimating time-to-contact (TTC) from retinal flow. Lee's model can deal with sparse flow but fails if the flow contains a rotational component. Koenderink's model, based on div, can deal with rotation but fails if the flow is sparse or if the world does not vary coherently in depth. Two new models were developed by representing retinal flow as the sum of an expansion and a rotation component. The first operates on pairs of points and can deal with sparse flow but fails if the world does not vary coherently in depth. Uniquely, this model provides TTC estimates without prior knowledge of either the focus of expansion (FOE) or focus of rotation (FOR). The second model estimates both the FOE and the FOR and then operates on a point-by-point basis. This model can deal with incoherent depth variations. We compared human performance with these different model properties by requiring subjects to estimate FOE and TTC from random-dot kinematograms. We used kinematograms depicting smooth planes and random 3-D clouds of points, and systematically varied the density of the flow. Performance was not substantially reduced by sparse flow or by incoherent depth, which argues against Koenderink's and the first of our own models. Performance remained good when rotation was added to the flow, which argues against Lee's model. Overall, the data favour a model that first decomposes flow into expansion and rotation components and then estimates TTC on a point-by-point basis.

A common first-order time-to-contact based control of hand-closure initiation in catching and grasping

2012 ◽  
Vol 31 (3) ◽  
pp. 529-540 ◽  
Author(s):  
Cornelis van de Kamp ◽  
Raoul M. Bongers ◽  
Frank T.J.M. Zaal
Keyword(s):  
Time To Contact ◽  
First Order

Estimation of time-to-contact from Tau-margin and statistical analysis of behavior

2016 ◽  
Author(s):  
Angel Juan Sanchez Garcia ◽  
Homero Vladimir Rios Figueroa ◽  
Antonio Marin Hernandez ◽  
Maria Karen Cortes Verdin ◽  
Gerardo Contreras Vega
Keyword(s):  
Statistical Analysis ◽  
Time To Contact ◽  
Estimation Of Time
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