search for: saccades

Displaying 3 results from an estimated 3 matches for "saccades".

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2009 Aug 03
1
selectively altering variable value
Hello, I have run an eye-tracking experiment for which I now like to analyse the saccades. Participants looked from a fixation cross (ia = 5) to the target area (ia = 4) in following example of a data frame. ia = 9 stands for everything else. A saccade is indicated by saccade = 1. Sometimes the saccade just ends before the target area (see below). This is due to the parameters that dete...
2009 Jan 31
1
Splitting a data frame with break points where factor changes value
I have a data frame called s3. This data frame has a column called saccade which has two levels 1 and -1. > head(s3$saccade, 100) [1] NA NA NA NA -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 [26] -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 1 1 1 [51] 1 1 1 1 1 1 1 1 1 1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 [76] -1 -1 -1 -1 -1
2009 May 12
3
What's the best way to tell a function about relevant fields in data frames
Hi list, I have a function that detects saccadic eye movements in a time series of eye positions sampled at a rate of 250Hz. This function needs three vectors: x-coordinate, y-coordinate, trial-id. This information is usually contained in a data frame that also has some other fields. The names of the fields are not standardized. > head(eyemovements) time x y trial 51