Merge pull request #15 from zuxfoucault/master

add fiff_readout_eventlist.m; extract events from raw file

matlab/mne_find_events.m

@@ -0,0 +1,97 @@
+function [eventlist] = mne_find_events(fname, stim_channel, consecutive, output)
+%
+%
+%   [eventlist] = mne_find_events(fname, stim_channel, consecutive, output)
+%
+%   Find event from raw file
+%
+%   fname        - string; .fiff raw data file name
+%   stim_channel - int; the channel that record event
+%   consecutive  - bool | 'increasing'
+%                  If True, consider instances where the value of the events
+%                  channel changes without first returning to zero as multiple
+%                  events. If False, report only instances where the value of the
+%                  events channel changes from/to zero. If 'increasing', report
+%                  adjacent events only when the second event code is greater than
+%                  the first.
+%   output       - 'onset' | 'offset' | 'step'
+%                  Whether to report when events start, when events end, or both.
+%
+%   eventlist    - size = (n_events, 3)
+%                  The first column contains the event time in samples and the third
+%                  column contains the event id. If output = 'onset' or 'step', the
+%                  second column contains the value of the stim channel immediately
+%                  before the event/step. For output = 'offset', the second column
+%                  contains the value of the stim channel after the event offset.
+%
+%   Authors: Fu-Te Wong (zuxfoucault@gmail.com),
+%            Chien-Chung Chen / Visual Neuroscience Lab, National Taiwan University
+%   Version 1.0 2017/9/17
+%   License: BSD (3-clause)
+
+raw = fiff_setup_read_raw(fname);
+[data, times] = fiff_read_raw_segment(raw);
+pick = stim_channel; % stim_channel
+
+changed = diff(data(pick, :));
+changed_idx = find(changed ~= 0);
+if length(changed_idx) == 0,
+    eventlist = zeros(1,3);
+    return
+end
+
+pre_step = data(pick, changed_idx);
+changed_idx = changed_idx + 1;
+post_step = data(pick, changed_idx);
+changed_idx = changed_idx + double(raw.first_samp - 1);
+eventlist = cat(2, changed_idx', pre_step', post_step');
+
+
+if strcmpi(consecutive, 'increasing'),
+    onsets = eventlist(:, 3) > eventlist(:, 2);
+    offsets = (onsets | eventlist(:, 3) == 0) & eventlist(:, 2) > 0;
+end
+
+if strcmpi(consecutive, 'True'),
+    onsets = eventlist(:, 3) > 0;
+    offsets = eventlist(:, 2) > 0;
+end
+
+if strcmpi(consecutive, 'False'),
+    onsets = eventlist(:, 2) == 0;
+    offsets = eventlist(:, 3) == 0;
+end
+
+onset_idx = find(onsets);
+offset_idx = find(offsets);
+
+if length(onset_idx) == 0 | length(offset_idx) == 0,
+    eventlist = zeros(1,3);
+    return
+end
+
+% Delete orphaned onsets/offsets
+if onset_idx(1) > offset_idx(1),
+    disp('Removing orphaned offset at the beginning of the file.');
+    offset_idx = offset_idx(2:end);
+end
+
+if onset_idx(end) > offset_idx(end),
+    disp('Removing orphaned offset at the beginning of the file.');
+    onset_idx = onset_idx(1:end-1);
+end
+
+if strcmpi(output, 'onset'),
+    eventlist = eventlist(onset_idx, :);
+elseif strcmpi(output, 'step'),
+    idx = union(onset_idx, offset_idx);
+    eventlist = eventlist(idx);
+elseif strcmpi(output, 'offset'),
+    event_id = eventlist(onset_idx, 3);
+    eventlist = eventlist(offset_idx, :);
+    eventlist(:, 2) = eventlist(:, 3);
+    eventlist(:, 3) = event_id;
+    eventlist(:, 1) = eventlist(:, 1) - 1;
+else
+    error('Invalid output parameter: %s.', output);
+end