Package: nirs

Near-infrared spectroscopy nodes.

These nodes implement domain-specific methods for processing near-infrared spectroscopy (fNIRS) data. NIRS data requires a specific processing pipeline, which involves optionally Subtract Dark Intensity, Intensity to Optical Density, and Estimate Concentrations. Other nodes, such as HDDOT, TDDR and so forth may be inserted into the pipeline as well. Like other neural time series, NIRS data is typically characterized by a time axis and a space axis. Here, the space axis is expected to have not only a .positions array (3d sensor aka detector positions) but also .positions_source, which represents the light source positions for the respective channel, as well as optionally a .wavelengths array.

Nodes in this package:

• Add Probe Locations
  Assign probe locations to channels from an fNIRS device.

• CoV-Based Bad Channel Removal (NIRS)
  Remove channels with abnormal data from a continuous NIRS signal.

• Corr-Based Bad Channel Removal (NIRS)
  Remove channels with abnormal data from a continuous NIRS signal.

• Scalp Coupling Index Bad Channel Removal (NIRS)
  Remove channels with low scalp coupling correlation from NIRS signals.

• Baseline PCA
  Perform Baseline PCA artifact removal.

• Correlation-Based Signal Improvement (CBSI)
  Apply the Correlation-Based Signal Improvement method to enhance the HbO/HbR contrast and downweight artifacts.

• Concentrations to Optical Density
  Infer NIRS (delta-)optical density from chormophore (HbO, HbR) concentration changes.

• Estimate Concentrations
  Estimate chromophore concentrations (HbO, HbR) from delta-optical density (OD) at multiple wavelengths.

• Group Channels By Wavelengths
  Group channels into groups by wavelength.

• High Density Diffuse Optical Tomography
  Transform fNIRS optical densities into brain mesh images using optical tomography.

• Intensity to Optical Density
  Convert light intensity to delta-optical density (OD).

• Optode Attribution
  Attribute channel measures to optodes.

• Separate Channels by Distance
  Calculate the distance between channels and either remove or place into a separate chunk channels which fall either below or above the threshold.

• Subtract Dark Intensity
  Subtract dark intensity channels from intensity channels.

• Temporal Difference Distribution Repair (TDDR)
  This node implements the TDDR method for fNIRS motion artifact reduction.