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Mateusz at 14:59, 5 May 2021

2021-05-05T14:59:57Z

Mateusz at 14:41, 5 May 2021

2021-05-05T14:41:16Z

Mateusz at 14:33, 5 May 2021

2021-05-05T14:33:28Z

Mateusz at 14:30, 5 May 2021

2021-05-05T14:30:10Z

Mateusz at 14:26, 5 May 2021

2021-05-05T14:26:13Z

Mateusz at 14:17, 5 May 2021

2021-05-05T14:17:30Z

Mateusz at 14:16, 5 May 2021

2021-05-05T14:16:02Z

Robert: /* Data Compression */

2021-05-04T10:11:12Z

‎Data Compression

Robert: /* Data Compression */

2021-05-04T10:03:39Z

‎Data Compression

Robert: /* Target Data Formats */

2021-05-04T10:02:22Z

‎Target Data Formats

@@ Line 19: / Line 19: @@
 * The entire data set or between markers
 * The currently marked segment
-* Epochs around triggers
+* [[Export Single Trial Data|Epochs around triggers]]
 * Standard deviations from binary average files (<span style="color:#ff9c00;">'''*.fsg'''</span>)
@@ Line 65: / Line 65: @@
 * '''Continuous data'''. The whole data set or the data between markers are exported.
 * '''Marked segment.''' If a segment of data is highlighted, this radio button is enabled. Select Marked segment to export just this segment.
-* '''Epochs around triggers.''' Export data segments around triggers. If this item is selected, the two buttons <span style="color:#3366ff;">'''Interval'''</span>... and <span style="color:#3366ff;">'''Triggers'''</span>... are enabled. They allow to select the interval (cf ''Edit / Default'' ''Block Epoch''...), and choose among the available triggers (see ''Edit / Trigger Values''...). Note that the default block epoch values are persistent across BESA Research sessions. The trigger selection is not persistent!
+* '''Epochs around triggers.''' Export data segments around triggers. If this item is selected, the two buttons <span style="color:#3366ff;">'''Interval'''</span>... and <span style="color:#3366ff;">'''Triggers'''</span>... are enabled. They allow to select the interval (cf ''Edit / Default'' ''Block Epoch''...), and choose among the available triggers (see ''Edit / Trigger Values''...). Note that the default block epoch values are persistent across BESA Research sessions. The trigger selection is not persistent! You can read more about this option here: [[Export Single Trial Data]]
 * '''Standard Deviations (from fsg file only).''' If the average file was generated using the BESA Research ERP module, standard deviations are saved in the file. Check this item to export these values to an ASCII file.

@@ Line 2: / Line 2: @@
 |title = Module information
 |module = BESA Research Basic or higher
-|version = 6.1 or higher
+|version = BESA Research 6.1 or higher
 }}

@@ Line 109: / Line 109: @@
 * '''European Data Format (EDF+)''': Data are saved with the extension "<span style="color:#ff9c00;">'''.edf'''</span>". Export of '''Epochs around triggers''' to EDF+ is currently not possible.
-* '''Simple binary matrix''': Data are written to a floating point binary matrix with the extension "<span style="color:#ff9c00;">'''.dat'''</span>". The matrix has the dimension no of samples x no of channels. In addition, a header file with the extension "<span style="color:#ff9c00;">'''.generic'''</span>" is also written. The header file is a text file contains information about the number of channels, sampling rate, and number of samples. These follow the specifications of the Generic File Format that can also be read by BESA Research if the Generic Reader is installed. This data format can be useful as a means of transferring data to other programs (e.g. '''MATLAB''') in a relatively compact form. If the type of data to export is '''Epochs around triggers''', the epochs are concatenated in the same target file. In this case, the header file contains a line specifying the number of epochs (cf. ''Generic File Format''). The number of samples in each epoch is the total number of samples, divided by the number of epochs.
+* '''Simple binary matrix''': Data are written to a floating point binary matrix with the extension "<span style="color:#ff9c00;">'''.dat'''</span>". The matrix has the dimension no of samples x no of channels. In addition, a header file with the extension "<span style="color:#ff9c00;">'''.generic'''</span>" is also written. The header file is a text file contains information about the number of channels, sampling rate, and number of samples. These follow the specifications of the Generic File Format. This data format can be useful as a means of transferring data to other programs (e.g. '''MATLAB''') in a relatively compact form. If the type of data to export is '''Epochs around triggers''', the epochs are concatenated in the same target file. In this case, the header file contains a line specifying the number of epochs (cf. ''Generic File Format''). The number of samples in each epoch is the total number of samples, divided by the number of epochs.
 * '''Send To MATLAB''': The data are exported directly to MATLAB into the struct variable <code>besa_channels</code>. For more information on the data transfer from BESA Research to MATLAB, please refer to the Help chapter [[MATLAB_Interface | MATLAB interface]].

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 * '''Standard 81 electrode locations.''' EEG data are interpolated to a set of 81 electrodes on a standard head (average over 24 mainly Caucasian heads).
-* Export can be performed either with or without the currently selected filters. Press the <span style="color:#3366ff;">'''Filters'''</span>... button to change the current filter settings (see also ''Filters / Edit Filter Settings''...).
+* Export can be performed either with or without the currently selected filters. Press the <span style="color:#3366ff;">'''Filters'''</span>... button to change the current filter settings (see also ''Filters / Edit Filter Settings''...). Note that if artifact correction was performed and this checkbox is enabled, data will be exported with artifact correction.
 == Target Data Formats ==

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 The dialog is started when you select'' File / Export...'' or press the <span style="color:#3366ff;">'''WrS'''</span> button or select '''Write Segment''' in the right click context menu when a segment has been highlighted.
-The dialog is divided into four sections. Please read the following chapters for more details:
+The dialog is divided into four sections:
 * ''Data to export''. Describes which data are to be exported.
 * ''Montage and Filters.'' Which montage is to be exported, and whether or not filters are used.

@@ Line 34: / Line 34: @@
-Export is started either
+To start export you have to:
 * select File / Export...
 * press the <span style="color:#3366ff;">'''WrS '''</span>button.
 * for Send to Matlab only: select File / Send To MATLAB... This also opens the Export Dialog, but only the <span style="color:#3366ff;">'''Send To Matlab radio'''</span> button is enabled as target format in the dialog.

← Older revision		Revision as of 14:16, 5 May 2021
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	On export, you can choose to change the sampling rate.		On export, you can choose to change the sampling rate.

−	If exporting to BESA's binary format, you can optionally append the data to a preexisting data set, if sampling rates and the number of channels match~~. Therefore, please use the Combine Conditions module~~.	+	If exporting to BESA's binary format, you can optionally append the data to a preexisting data set, if sampling rates and the number of channels match.

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 When exporting to BESA binary format and ASCII multiplex formats, you can compress the data to save space. Here we describe properties and pitfalls of the compression algorithm.
 '''How compression works'''
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 For raw EEG data, we recommend using a step size of 0.5 µV.
 '''Different compression parameters for different data types (pitfalls!)'''
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 * '''Averages:''' We recommend that averaged ERPs are not compressed. Since the signals are generally much smaller than the raw data, compression will lead to unacceptable loss of data resolution.
 [[Category:Research Manual]]
 {{BESAManualNav}}

← Older revision		Revision as of 10:03, 4 May 2021
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	== Data Compression ==		== Data Compression ==

−	When exporting to BESA binary format, you can compress the data to save space. Here we describe properties and pitfalls of the compression algorithm.	+	When exporting to BESA binary format and ASCII multiplex formats, you can compress the data to save space. Here we describe properties and pitfalls of the compression algorithm.

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 The following target formats are available:
-* '''BESA binary''': Data are saved with the extension "<span style="color:#ff9c00;">'''.foc'''</span>" or "<span style="color:#ff9c00;">'''.fsg'''</span>". You can select whether to export with no compression (recommended for averages), or compressed (recommended for raw data). Note that compression can result in loss of resolution in averaged data. See ''Data Compression.''
+* '''BESA binary''': Data are saved with the extension "<span style="color:#ff9c00;">'''.foc'''</span>" or "<span style="color:#ff9c00;">'''.fsg'''</span>". You can select whether to export with no compression (recommended for averages), or compressed (recommended for raw data). Note that compression can result in loss of resolution in averaged data. See [[Export#Data_Compression|Data Compression]].
-* '''ASCII multiplexed''': Data are normally saved as text with the extension "<span style="color:#ff9c00;">'''.mul'''</span>". See ''ASCII multiplexed format'' for a description of the data format. If the type of data to export is '''Epochs''' '''around triggers''', one file is exported for each trigger, and the file extension is a number, starting with ".000", and continuing ".001", ".002", etc.
+* '''ASCII multiplexed''': Data are normally saved as text with the extension "<span style="color:#ff9c00;">'''.mul'''</span>". See [[ASCII_File_Format#ASCII_Multiplexed_file_format|ASCII multiplexed format]] for a description of the data format. If the type of data to export is '''Epochs''' '''around triggers''', one file is exported for each trigger, and the file extension is a number, starting with ".000", and continuing ".001", ".002", etc.
-* '''ASCII vectorized''': Data are normally saved as text with the extension "<span style="color:#ff9c00;">'''.avr'''</span>". See ''ASCII Multiplexed format ''for a description of the data format. If the type of data to export is '''Epochs around triggers''', one file is exported for each trigger, and the file extension is a number, starting with ".000", and continuing ".001", ".002", etc. The data are not average referenced before saving. They will only be average referenced if the data are exported using an average referenced '''Current montage'''. You are only allowed to export small segments in vectorized format. If you have selected '''Continuous data''', this item will be disabled if the data are longer than 20 s in duration.
+* '''ASCII vectorized''': Data are normally saved as text with the extension "<span style="color:#ff9c00;">'''.avr'''</span>". See [[ASCII_File_Format#ASCII_Vectorized_file_format|ASCII vectorized format]] for a description of the data format. If the type of data to export is '''Epochs around triggers''', one file is exported for each trigger, and the file extension is a number, starting with ".000", and continuing ".001", ".002", etc. The data are not average referenced before saving. They will only be average referenced if the data are exported using an average referenced '''Current montage'''. You are only allowed to export small segments in vectorized format. If you have selected '''Continuous data''', this item will be disabled if the data are longer than 20 s in duration.
 * '''European Data Format (EDF+)''': Data are saved with the extension "<span style="color:#ff9c00;">'''.edf'''</span>". Export of '''Epochs around triggers''' to EDF+ is currently not possible.