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ImpedanceChannelRejection

Remove bad channels based on their impedance.

This node is meant to be used on data recorded from hardware with built-in impedance measurement capabilities. Specifically, the data is assumed to have an embedded square wave that is aligned with the sampling time points of the system, and the amplitude of that square wave can be used to infer the impedance (i.e., electrical resistance) of the EEG/EXG sensor. As of this writing, only Cognionics hardware is known to be compatible with this node. If this filter is used on streaming data and has not yet been calibrated, then it will first buffer n seconds of calibration data to determine what channels to keep, before any output is produced. The set of retained channels is considered "trainable state", and can be saved in model files for later reuse. Version 1.0.0

Ports/Properties

data

Data to process.

  • verbose name: Data
  • default value: None
  • port type: DataPort
  • value type: Packet (can be None)
  • data direction: INOUT

threshold

Impedance threshold (Mohms). Channels with impedance higher than this will be rejected.

  • verbose name: Impedance Threshold
  • default value: 2
  • port type: IntPort
  • value type: int (can be None)

period

Embedded impedance signal period (samples). This is the period, in samples, of the impedance signal that is embedded in the data by the sensor.

  • verbose name: Impedance Signal Period
  • default value: 4
  • port type: IntPort
  • value type: int (can be None)

unit_conversion

Factor for converting signal units to volts. This is usually taken care of by the data acquisition system.

  • verbose name: Unit Conversion Factor
  • default value: 1e-06
  • port type: FloatPort
  • value type: float (can be None)

calib_seconds

Amount of data, in seconds, to gather for calibration. When this filter is run online and has not yet been calibrated, then it will first buffer this many seconds of data in order to compute its measures before any output is produced.

  • verbose name: Gather This Much Calibration Data
  • default value: 15
  • port type: IntPort
  • value type: int (can be None)

set_breakpoint

Set a breakpoint on this node. If this is enabled, your debugger (if one is attached) will trigger a breakpoint.

  • verbose name: Set Breakpoint (Debug Only)
  • default value: False
  • port type: BoolPort
  • value type: bool (can be None)

metadata

User-definable meta-data associated with the node. Usually reserved for technical purposes.

  • verbose name: Metadata
  • default value: {}
  • port type: DictPort
  • value type: dict (can be None)