pva: Position, Velocity, Acceleration
In RyanHope/gazetools: Gazetools

Takes standard eye tracker gaze information and computes smoothed position, velocity and acceleration profiles using a Savitzky-Golay filter.

1 2	pva(x, y, samplerate, rx, ry, sw, sh, ez, ex = 0, ey = 0, timestamp = -1, minsac = 0.02, vt = 1000, at = 1e+05, blinks = NULL)

`x`	the horizontal coordinate of a point on a screen (pixels)
`y`	the vertical coordinate of a point on a screen (pixels)
`samplerate`	the number of samples taken in one second of time
`rx`	the horizontal resolution of the screen (pixels)
`ry`	the vertical resolution of the screen (pixels)
`sw`	the physical screen width (mm)
`sh`	the physical screen height (mm)
`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
`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
`blinks`	a vector of class `logical` indicating blinks or otherwise bad data in the velocity vector

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

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