ctf_read_res4

ctf_read_res4 - function [ctf] =...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
function [ctf] = ctf_read_res4(folder,VERBOSE,COEFS); % ctf_read_res4 - Read a CTF .res4 file % % ctf = ctf_read_res4( [folder], [verbose], [coefs]) % % This function reads the resource information from a CTF .ds folder. This % resource information must be read before reading the .meg4 data file. % All input arguments are optional. % % INPUTS % % folder: the .ds directory containing the data to be read. With % no input, it will prompt with a gui folder locator % (called by ctf_folder). % % verbose: If verbose = 1, display 'ctf.setup' structure (default) % If verbose = 0, do not display 'ctf.setup' structure % % coefs: an option to read the MEG sensor and reference coefficients, % which give the weights for calculation of synthetic 2nd or 3rd % order gradiometers. % If coefs = 1, read the sensor coefficients % If coefs = 0, do not read the sensor coefficients (this is the % default because it is assumed that data preprocessing with % CTF tools has already applied AND saved a synthetic % gradiometer transformation for the meg4 data file). The % ctf.sensor.info(x).grad_order_no will indicate the gradient % order of the data (this only applies to MEG sensors, other % channels have zero values). % % OUTPUTS % % ctf.folder - path of the .ds folder % % ctf.res4.file - data file path/name % ctf.res4.header - data format header % % ctf.setup - a header structure consisting of date, time, run name, run % title, subject, run description, operator, number of channels, number % of samples, sample rate, number of trials, duration, pretrigger_samples, % sensor filename, head zeroing, and number of filters. % % ctf.sensor.index - a sensor structure consisting of EEG sensors, MEG % sensors, reference sensors, and other sensors. % % ctf.sensor.info - a structure with gain and offset information consisting % of proper gain, Q gain, io gain, io offset, and index. % % The proper gain is the channel-wide constant quotient of a value in raw % units and a value in user units. (For EEG this is one because there is % no conversion; i.e., the values are in volts, for MEG there is conversion % between phi0 and teslas). % proper gain = raw value / user value % % The Q-gain is used to convert the 32-bit integers produced by the % electronics to the raw values stored in the data file. % raw value = 32 bit value / Q gain %
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
% The IO-gain is essentially a correction factor that is applied to the % raw values before they are stored to disk. % % % <>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> % < > % < DISCLAIMER: > % < > % < THIS PROGRAM IS INTENDED FOR RESEARCH PURPOSES ONLY. > % < THIS PROGRAM IS IN NO WAY INTENDED FOR CLINICAL OR > % < OFFICIAL USE. > % < > % <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<> % % $Revision: 1.1 $ $Date: 2009/01/30 03:49:27 $ % Copyright (C) 2003 Darren L. Weber % % This program is free software; you can redistribute it and/or % modify it under the terms of the GNU General Public License % as published by the Free Software Foundation; either version 2
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/07/2010 for the course ENG 42336 taught by Professor Thomasholland during the Spring '10 term at UC Davis.

Page1 / 11

ctf_read_res4 - function [ctf] =...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online