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Home R Playground R Playground Laubrock (in preparation). eyetrackR: an R package for the analysis of eye movement data

Laubrock (in preparation). eyetrackR: an R package for the analysis of eye movement data

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eyetrackR

Description

eyetrackR is an R package providing a set of utility functions for the analysis of eyetracker data. Currently it is geared towards, but not limited to, eye movements during reading. Starting from the raw time series of x and y samples, the package allows automated classification into saccades and fixations, with adjustable saccade detection parameters. Saccade detection results in a fixation sequence. From this sequence, given additional input about the reading material, aggregate measures such as gaze durations (first-path dwell time on a word) or skipping probabilities are computed. The data are shaped into a format that facilitates analyses using a distributed-processing approach, i.e., taking into account influences of the neighboring words (or fixations) on the current fixation duration. Sample analyses demonstrate how these measures can be analyzed as a function of word and reader parameters, using linear mixed effects models.

 

The package also contains a number of utility functions, such as parseq, firstpass, plotsacc, and computeReadingMeasures.

See help files for individual parts listed below.

Installation

Download and save package to a directory, then from within R either install as a local source package using the package manager GUI or setwd() to that directory and type

 

install.packages("eyetrackR_0.16.tar.gz", repos = NULL, type="source")

 

Procedure

1. data preprocessing

(edf to ascii conversion, .dat, .msg, and .msg2 file creation and cleanup)

  • preprocess (requires installed edf2asc utility by SR research)

(case management)

  • xallsac_l3 (demo)

2. message file parser

  • parse_msg_file (demo)
  • parms1 # usage: data(parms1); contains detection parameters
  • readSubjects

3. (micro-)saccade detection

  • vecvel
  • microsacc
  • binsacc
  • saccpar

4. analysis of fixation sequences

(currently mainly contains demos)

  • xSetup1_l3 (demo)
  • computeReadingMeasures
  • xIndex_fix_l3_logical (demo)
  • xSetup2_l3 (demo)

5. definition of aggregate measures

(currently only contains demos)

  • xSetup2.2_dvmat_l3 (demo)

6. sample statistical analysis

 

Author(s)

Jochen Laubrock with Reinhold Kliegl, Ralf Engbert, Sarah Risse, Daniel Schad, Michael Dambacher

Maintainer: Jochen Laubrock

References

Laubrock & Kliegl (in preparation). eyetrackR: an R package for the analysis of eye movement data.

Engbert, R., & Mergenthaler, K. (2006) Microsaccades are triggered by low retinal image slip. Proceedings of the National Academy of Sciences of the United States of America, 103, 7192–7197.

Examples

#############################################################
## (micro-)saccade detection
#############################################################
data(trial4)
# names(trial4) <- c("t", "xl", "yl", "pl", "xr", "yr", "pr")

SAMPLING <- 500
VFAC <- 5
MINDUR <- 3

vl <- vecvel(trial4[,c("xl", "yl")], SAMPLING, 2)
sacl <- microsacc(trial4[,c("xl", "yl")], vl, VFAC, MINDUR)

vr <- vecvel(trial4[,c("xr", "yr")], SAMPLING, 2)
sacr <- microsacc(trial4[,c("xr", "yr")], vr, VFAC, MINDUR)

sacb <- binsacc(sacl$sac, sacr$sac)
sacb2 <- saccpar(sacb$sac)

#############################################################
## sentence corpus
#############################################################
data(PSC2.DWDS)
example(PSC2.DWDS)

#############################################################
## reading measures
#############################################################
data(a)
a2 <- computeReadingMeasures(a)
summary(a2)

 

 


 

 

 

 

 

To download, use right-click or CTRL-click and then "save as..."
Download this file (eyetrackR_0.16.tar.gz)eyetrackR_0.16.tar.gz[eyetrackR: R package supporting the analysis of eye movement data][ ]1897 Kb26/06/2012 21:07
Download this file (Eyetracking_Datenanalyse_Laubrock.pdf)Eyetracking_Datenanalyse_Laubrock.pdf[(in German): Presentation describing eye movement data analysis, with some eyetrackR examples][2]10389 Kb15/09/2010 19:04
Download this file (Aufgaben_web.pdf)Aufgaben[(in German): exercises using eyetrackR][3]3644 Kb15/09/2010 19:05
Last Updated on Tuesday, 26 June 2012 21:09  

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