To open a data file, drag-and-drop it into the program's main window. Alternatively, double-click a .dat file in Windows Explorer, and choose BCI2000 FileViewer when prompted for an application program to associate with the .dat extension.
User interface elements for browsing are located below the signal display.
- |<< and >>| move to beginning/end of file;
- << and >> move forward/backward by entire pages (i.e., the amount of time displayed in the window);
- < and > move forward/backward by sample blocks;
- Zoom in and Zoom out enlarge/shrink the time axis;
- the position field displays the current position in hh:mm:ss format, followed by the total length of the file. Entering a value in seconds, or in hh:mm:ss format, will move the center of the display to the specified position.
Selecting States and Channels for Display
Once a file is opened in BCI2000 Viewer, the area to the right displays a list of state variables and brain signal channels contained in the data file. By default, all channels are selected for display, and none of the states are. To display one or more state, mark the respective checkbox.
State names and values are displayed above the signal; whenever a state changes its value, a vertical line indicates the respective point in time, and the state's new value appears at the top end of that line.
Similar to the signal display in the operator module, display properties may be changed from the View menu (which is reduplicated as a context menu that appears by right-clicking the signal display).
Also, the following keyboard shortcuts are provided:
|up/down||back/forward one channel,|
|page-up/page-down||back/forward one screenful of channels,|
|'b'/space||same as page-up/page-down ('less'-like shortcuts),|
|-/+||reduce/enlarge the signal,|
|left/right||slow down/speed up the time sweep,|
|home/end||jump to the first/last screenful of channels,|
|typing a number and pressing return (or 'g')||jump to the specified channel number.|
When the signal's physical unit is displayed, it is represented as a white bar:
In the example, there are white markers above and below the bar, indicating the range corresponding to the value written in the bar. These markers may be missing; then the range corresponds to the height of the bar itself.
Finally, the physical unit may be displayed with a white marker attached to the bar:
This display is used for nonnegative signals. Here, the physical unit corresponds to the distance of the white marker to the signal's baseline.
Choosing Signal Colors
Clicking Choose Signal Colors... from the context menu will open up a color chooser dialog. This dialog provides fields for "User defined colors" to the left, defining a list of channel colors, terminated with a black entry.
Signal colors are taken from these fields in the order in which they appear; when there are more signals displayed than colors defined, colors will be re-used in order.