VIEWEDF Version 3.0 Alpha

VIEWEDF is a program developed to display European-Data-Format files. Additionally the program is able to use so-called plugin programs. Such a plugin can be used to perform transformations of the original EDF data (e.g., re-referencing of EEG signals).

Information on the screen

Menu structure

Shortcut keys

Plugin programs

EDF data structure

Download

Requirements

VIEWEDF runs only on Matlab Version >= 5.0
Plugins which are used must be placed in the search path.

Using VIEWEDF

Display

This image is a sample display

Displayed Information

Time	starting time of the shown record(s) in hh:mm:ss
Total length	length of the EDF file
Displayed	duration of the displayed record(s)
File	file-name
Scrollbar	position within the (longest) file

Besides each plot

Label	channel-label
Button	displays a dialog with channel information

Menus

File

Open EDF	select an EDF file to open
Close EDF	close an EDF file
Add Plugin	adds an extension to the viewer (details)
Remove Plugin	removes an extension
Print	prints the current display
Assign	saves channels to Matlab variable
Exit	aborts the viewer

Display

File Info	display the information contained in the EDF header
Goto Record	move to a record in the file
Records on Screen	change number of records that are simultaniously on the screen
Channels	select which channels to display

Options

Update Plugins	if selected plugin-data will be updated every time the display changes
Plugin	plugin specific settings (details)

Help	loads this file
About	copyright information

Shortcut keys

+	moves forward one page (as > in the menu)
-	moves backwards one page

Plugin programs

Plugins can be used to extend the functionality of the viewer. Helpful functions include re-referencing of EEG signals, artefact detection, ... Plugins can be loaded into the viewer using the Add Plugin dialog. The dialog allows to specify

name of the plugin function (a file named function.m must be in the search path)
optional label for the data produced by the plugin.
optional parameters for the plugin. These parameters are passed as a string value in UserData when the plugin is called the first time.

Interface for plugin functions

The definition of a plugin must look as follows

function [ResEDF, ResUserData] = plugname(EDF, UserData, Opt)

Parameters passed to the plugin

EDF
current EDF data of the EDF file

UserData
data used by the plugin. Any plugin specific setting may be stored in UserData. This data is guaranteed not to be change by any other function. UserData has been added to avoid the use of global variables. The first time a plugin is called UserData contains the parameters entered in the Add Plugin dialog.

Opt
strings used to request special actions. Currently used options are
Reset : requires the plugin to reset all internal variables. This request is used if the plugin is called the first time and if a new EDF file is opened.

Menu : is used if the plugin specific menu has been selected. Plugins may implement dialogs to set specific options. This option can be ignored if no settings are necessary.

Output of a plugin

ResEDF
data calculated by the plugin. The data must be in EDF format. Currently VIEWEDF2 requires following EDF variabled to be set properly:
Head.NS, Head.PhysMin, Head.PhysMax, Head.SPR, Head.Label, Record

ResUserData
UserData of the plugin. This data is passed to the plugin the next time it is called.

Replace
If 1 the original data of the EDF file is not displayed. This option is useful if EEG channels are for exapmle re-referenced.

The output of a plugin must be correct even if options are passed to the plugin!

EDF data-structure

VIEWEDF uses the EDF data-structure for data-exchange. This structure contains all information found in an EDF file.

Record	Data read from the EDF file. The length of this array is determined by the signal with the highest sampling rate. Signals with lower sampling rates are zero padded to achieve the same length.
MX	?
Idx	list of records currently loaded into Record
Head	EDF file-header information
Head.FILE	EDF-File related information
Head.FILE.FID	File-handle
Head.FILE.Open	1 if file is currently open
Head.FILE.Ext	file extension
Head.FILE.Name	file-name (without extension)
Head.FILE.Path	path to file
Head.FILE.Pos	Positioning information in the file
Head.FileName	full file-name
Head.Version	version of EDF format
Head.PID	patient identification
Head.RID	recording identification
Head.T0	start time and date of recording
Head.HeadLen	length of header (in Bytes)
Head.NRec	number of data-records in file
Head.Dur	duration of a data-record in sec
Head.NS	number of signals in a data-record
Head.Label	label for each signal
Head.Transducer	transducer type
Head.PhysDim	physical dimension
Head.PhysMin	physical minimum
Head.PhysMax	physical maximum
Head.DigMin	digital minimum
Head.DigMax	digital maximum
Head.PreFilt	prefilter information
Head.SPR	samples per record
Head.Cal	?
Head.Off	?
Head.Calib	?
Head.SampleRate	sampling rate
Head.Chan_Select	?
Head.ChanType	?
Head.AS	?
Head.AS.spb	?
Head.AS.IDX2	?

VIEWEDF documentation written by Herbert Ramoser, 09/18/1998

EDF	current EDF data of the EDF file
UserData	data used by the plugin. Any plugin specific setting may be stored in UserData. This data is guaranteed not to be change by any other function. UserData has been added to avoid the use of global variables. The first time a plugin is called UserData contains the parameters entered in the Add Plugin dialog.
Opt	strings used to request special actions. Currently used options are Reset : requires the plugin to reset all internal variables. This request is used if the plugin is called the first time and if a new EDF file is opened. Menu : is used if the plugin specific menu has been selected. Plugins may implement dialogs to set specific options. This option can be ignored if no settings are necessary.

ResEDF	data calculated by the plugin. The data must be in EDF format. Currently VIEWEDF2 requires following EDF variabled to be set properly: Head.NS, Head.PhysMin, Head.PhysMax, Head.SPR, Head.Label, Record
ResUserData	UserData of the plugin. This data is passed to the plugin the next time it is called.
Replace	If 1 the original data of the EDF file is not displayed. This option is useful if EEG channels are for exapmle re-referenced.