FT_DETECT_MOVEMENT
Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_detect_movement”.
FT_SACCADE_DETECTION performs micro/saccade detection on time series data over multiple trials Use as movement = ft_detect_movement(cfg, data) The input data should be organised in a structure as obtained from the FT_PREPROCESSING function. The configuration depends on the type of computation that you want to perform. The configuration should contain: cfg.method = different methods of detecting different movement types 'velocity2D', Micro/saccade detection based on Engbert R, Kliegl R (2003) Vision Res 43:1035-1045. The method computes thresholds based on velocity changes from eyetracker data (horizontal and vertical components). 'clustering', Micro/saccade detection based on Otero-Millan et al., (2014) J Vis 14 (not implemented yet) cfg.channel = Nx1 cell-array with selection of channels, see FT_CHANNELSELECTION for details, (default = 'all') cfg.trials = 'all' or a selection given as a 1xN vector (default = 'all') METHOD SPECIFIC OPTIONS AND DESCRIPTIONS VELOCITY2D VELOCITY2D detects micro/saccades using a two-dimensional (2D) velocity space velocity. The vertical and the horizontal eyetracker time series (one eye) are transformed into velocities and microsaccades are indentified as "outlier" eye movements that exceed a given velocity and duration threshold. cfg.velocity2D.kernel = vector 1 x nsamples, kernel to compute velocity (default = [1 1 0 -1 -1].*(data.fsample/6); cfg.velocity2D.demean = 'no' or 'yes', whether to apply centering correction (default = 'yes') cfg.velocity2D.mindur = minimum microsaccade durantion in samples (default = 3); cfg.velocity2D.velthres = threshold for velocity outlier detection (default = 6); The output argument "movement" is a Nx3 matrix. The first and second columns specify the begining and end samples of a movement period (saccade, joystic...), and the third column contains the peak velocity/acceleration movement. This last thrid column will allow to convert movements into spike data representation, making the spike toolbox functions compatible (not implemented yet). To facilitate data-handling and distributed computing you can use cfg.inputfile = ... cfg.outputfile = ... If you specify one of these (or both) the input data will be read from a *.mat file on disk and/or the output data will be written to a *.mat file. These mat files should contain only a single variable, corresponding with the input/output structure. See also FT_PLOT_MOVEMENT (not implemented yet)