Probe Placement Variability only performed on long separation channels

[morrisvanegas]

Using AtlasViewer v2.12.12
Attempting to perform inter-subject variability using the guidance of this link: https://openfnirs.org/wp-content/uploads/2020/05/fNIRS_workshop_day3_ProbeLocalizationError.pdf

I have 30 optodes (15 sources, 15 detectors) and 5 landmarks, however, the output of Tools -> Probe Placement Variability only displaces 20 optodes despite my loaded probe displaying all 30 optodes. Digging deeper, I see that line 63 in AtlasViewer/Probe/plotProbePlacementVariation.m sets a short separation threshold of 15mm. To analyze my probe, I've changed ssThresh to 5mm (below the shortest length channel in my probe).

1. Is there a way to have the user define the ssThresh in the GUI before running Probe Placement Variability?
2. In general, what is the reasoning behind excluding channels < 15mm? Is it assumed that the variation in optode positioning will be larger than the length of a short-separation channel (15mm) that it's not worth investigating?

Standard Deviation results show 20 optodes.

Results table showing 20 optodes

Original digitized optodes using Polhemus displaying 30 optodes and 5 landmarks

Loaded probe in AtlasViewer showing 30 optodes