method_nh

Extract saccades using an algorithm proposed by Nyström and Holmqvist (2010) tools:::Rd_expr_doi("10.3758/BRM.42.1.188").

A modular and extendable approach to extract (micro)saccades from gaze samples via an ensemble of methods.
Although there is an agreement about a general definition of a saccade, the more specific details are harder to agree upon.
Therefore, there are numerous algorithms that extract saccades based on various heuristics, which differ in the assumptions about velocity,
acceleration, etc. The package uses three methods (Engbert and Kliegl (2003) <doi:10.1016/S0042-6989(03)00084-1>,
Otero-Millan et al. (2014)<doi:10.1167/14.2.18>, and Nyström and Holmqvist (2010) <doi:10.3758/BRM.42.1.188>)
to label individual samples and then applies a majority vote approach to identify saccades. The package includes three
methods but can be extended via custom functions. It also uses a modular approach to compute velocity and
acceleration from noisy samples. Finally, you can obtain methods votes per gaze sample instead of saccades.

Alexander (Sasha) Pastukhov

saccadr

Extract Saccades via an Ensemble of Methods Approach

Alexander Pastukhov

method_nh function

<dl><dt>x</dt>
<dd>Gaze x coordinate, _arbitrary units_ as threshold velocity is computed in units of standard deviation.</dd>
<dt>y</dt>
<dd>Gaze y coordinate, _arbitrary units_ as threshold velocity is computed in units of standard deviation.</dd>
<dt>vel</dt>
<dd>Velocity <code>data.frame</code> with columns <code>x</code>, <code>y</code>, <code>amp</code>.</dd>
<dt>acc</dt>
<dd>Acceleration <code>data.frame</code> with columns <code>x</code>, <code>y</code>, <code>amp</code>.</dd>
<dt>sample_rate</dt>
<dd>Sample rate in Hz.</dd>
<dt>trial</dt>
<dd>Trial id, so that trial borders are respected when computing velocity and saccades.</dd>
<dt>options</dt>
<dd>Named list with method options. See details for further information.</dd></dl>

Arguments

Extract saccades using an algorithm proposed by Nyström and Holmqvist (2010) tools:::Rd_expr_doi("10.3758/BRM.42.1.188"). — method_nh

<dl>

<dt>x</dt>
<dd>Gaze x coordinate, _arbitrary units_ as threshold velocity is computed in units of standard deviation.</dd>


<dt>y</dt>
<dd>Gaze y coordinate, _arbitrary units_ as threshold velocity is computed in units of standard deviation.</dd>


<dt>vel</dt>
<dd>Velocity <code>data.frame</code> with columns <code>x</code>, <code>y</code>, <code>amp</code>.</dd>


<dt>acc</dt>
<dd>Acceleration <code>data.frame</code> with columns <code>x</code>, <code>y</code>, <code>amp</code>.</dd>


<dt>sample_rate</dt>
<dd>Sample rate in Hz.</dd>


<dt>trial</dt>
<dd>Trial id, so that trial borders are respected when computing velocity and saccades.</dd>


<dt>options</dt>
<dd>Named list with method options. See details for further information.</dd>

</dl>

method_nh: Extract saccades using an algorithm proposed by Nyström and Holmqvist (2010) tools:::Rd_expr_doi("10.3758/BRM.42.1.188").

Description

Usage

Value

Arguments

Details

See Also

Examples