SignalToNoise¶
Signal to noise, computed as the log ratio of signal (filtered) and noise (unfiltered - filtered) data segments, with a baseline removed.
This node expects the data to contain event markers which will be used to create the segments on which the SnR is computed, for example, markers indicating the start of a trial, and the markers in question must already be assigned as targets (using AssignTargets). For each filtered segment, baseline of a specified length immediately preceeding the event marker is subtracted prior to filtering. The signal to noise ratio is stored in a Feature axis with feature name "SNR". The measure is averaged over time and the Time axis is removed. The original signal data is not passed through. This node is for offline, non-segmented data only. If this is to be computed on a particular stream only, use ExtractStreams before this node to separate that stream along with the event marker stream. Version 1.0.2
Ports/Properties¶
data¶
Data to process.
frequency_range¶
Frequency range representing the range within which the target signal is typcially found, depending on the modality. For example, for HbO/HbR concentration (NIRS), this would typically be [0.01, 0.1].
signal_segment_length¶
The length, in seconds, of the "signal" segments, starting from the target event markers (which should already be assigned as targets prior to this node or be the only markers remaining in the packet). These are the segments on which the signal to noise ratio will be computed. This same value is also used extract the baseline segment of equal length immediately preceeding the signal segment (therefore, immediately preceeding the target event markers) that will be subtracted from the signal segment.
set_breakpoint¶
Set a breakpoint on this node. If this is enabled, your debugger (if one is attached) will trigger a breakpoint.
metadata¶
User-definable meta-data associated with the node. Usually reserved for technical purposes.