gaze_velocity: Gaze Velocity

In RyanHope/gazetools: Gazetools

Description

Computes instantaneous gaze velocity using a Savitzky-Golay filter.

Usage

gaze_velocity(x, y, ez, ex = 0, ey = 0, timestamp = -1, blinks = NULL,
  samplerate, screen.resolution, screen.dimensions, minsac = 0.02,
  vt = 1000, at = 1e+05)

Arguments

x	the horizontal coordinate of a point on a screen (pixels)
y	the vertical coordinate of a point on a screen (pixels)
ez	the perpendicular distance from the viewer to the screen (mm)
ex	the horizontal offset of the viewer from screen center (mm)
ey	the vertical offset of the viewer from screen center (mm)
timestamp	vector of class "numeric" containing the external time corresponding to raw gaze samples
blinks	a vector of class logical indicating blinks or otherwise bad data in the velocity vector
samplerate	the number of samples taken in one second of time
screen.resolution	vector of class "numeric", the resolution of the screen (pixels)
screen.dimensions	vector of class "numeric", the physical dimensions of the screen (mm)
minsac	the minimum saccade duration in seconds
vt	the max peak velocity allowed for good data
at	the max peak acceleration allowed for good data

Examples

data(smi)
d <- with(smi, gaze_velocity(smi_sxl, smi_syl,
                             smi_ezl, smi_exl, smi_eyl,
                             timestamp=smi_time, blinks=(smi_dyl==0),
                             500, 1680, 1050, 473.76, 296.1)
d

d <- with(highspeed, gaze_velocity(x,y,1250,1024,768,.38,.30,.67,
                         blinks=(x==0|y==0)))
d

RyanHope/gazetools documentation built on May 9, 2019, 10:38 a.m.