Troubleshooting
What are "detectors" vs "detector cards" and how many should there be? Detectors are the individual optodes that pick up light. For our current NIRx system, there are 8. Detector cards are the bundles of detectors that plug into the chassis. For our current NIRx system, there are 2 cards (4 detectors on each card).
What should I do if the calibration doesn't come back all green? Remove target optodes from the cap and use a tool to move any hair out of the way. If this is done multiple times with no success, determine whether you would like to continue collecting data or thank the participant for their time and send them on their way. Some yellow signals may be ok but if there are too many yellows or any red/white signals, you may be wasting your time collecting bad data.
The results of my phantom test were not good, how can I check if an optode is bad? You should first perform a phantom test calibration to pinpoint which source/detectors may be bad. If poor results appear on the test, check the optodes accordingly. For the sources, ensure the fNIRS system is on and launch NIRStar. Select "PREVIEW" from the Main Functions menu. A red flashing light should emit from the source. For the detectors, CAREFULLY remove a detector cable from the detector card on the chassis. Shine a flashlight into one end of the detector and check the other end. You should see the light emitting through the other side.
For further questions, reference the resources below: