CorrelationMetric¶
A meta-node that repairs bad channels and evaluates the correlation of each channel to its neighbors.
Version 1.1.0
Ports/Properties¶
data¶
Data to process.
min_corr¶
Correlation threshold. Higher values (above 0.7) are more aggressive and will cause channels to be repaired even when they have only moderate artifacts. Values below 0.5 would be considered rather lax (i.e., only the worst channel artifacts get repaired). This threshold is based on the correlation between a channel and what one would expect the channel to be based on the other channels.
window_len¶
Window length to compute correlations. The length of the time windows, in seconds, for which channel quality is computed, i.e. time granularity of the measure. Ideally this is short enough to reasonably capture periods where artifacts happen, but no shorter (otherwise the statistic becomes too noisy and thus unreliable).
subset_size¶
Size of random channel subsets to use. This is for use in a RANSAC estimator, and can be given as number of channels or, if below 1.0, as a fraction of the total number of channels. Smaller subsets (e.g., 0.1-0.15) together with higher number of Ransac samples (e.g., 50-100) gives a more robust estimate, at increased computational cost, which can be quite substantial.
calib_seconds¶
Amount of data, in seconds, to buffer for calibration on streaming data. For offline (non-streaming) data, set to 0.
num_samples¶
Number of random channel subsets to use. This for use in a RANSAC estimator. Higher numbers (e.g., 50-100) together with smaller subset sizes (e.g., 0.1-0.15) give a more robust estimate, at higher computational cost.
location_wise_corr¶
Calculate correlation based on channel locations, instead of calibration statistics (experimental). If the amount of collected calibration data was very small, then using channel locations, if known a priori, can result in better correlation statisics, and thus better identification of artifacts. This is primarily for the case where this method is used without a preceding removal of bad channels, and with little initial calibration data.
linenoise_aware¶
Use line-noise aware processing. Whether the operation should be performed in a line-noise aware manner. If enabled, the correlation measure will not be affected by the presence or absence of line noise. May be turned off if line noise has already been removed.
calibration_backend¶
Backend for initializing the RANSAC projection. This is a one-time computation, which can however be fairly time consuming for many channels. The multiprocessing, loky, and nestable backends support both the case where location_wise_corr is enabled (use locations) and disabled (use data statistics). Use serial on platforms where multiprocessing is not available (e.g., Android).
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.