I encountered a problem when importing the ".nirs" file according to the tutorial on the official website. I collected some near-infrared data, but the 3D coordinates of the probe did not match the head mold during the import process into the Brainstorm.The following is a detailed description:
The nirs channel file used in the tutorial has 3D coordinates of source and detector, so it can correctly display the relative positions of the probe and the head mold (Fig.1).
However, the NIRS file output by the near-infrared device I am using only contains the relative position between probes, lacking the relative position relationship with the head mold (Fig.2).
These are the comparison of the spatial coordinates between the official website sample file and the file collected by my device (Fig.3 and Fig.4). I'm not sure which reference system these spatial coordinates use, all coordinate values are less than 1, seems to be a vector algorithm?
I have one file containing the spatial coordinates of the probes, whose file type is ".csv" (Fig.5); one file containing coordinates of reference points (Lz, AR, AL, Cz, etc). Due to the difference in the reference system between the MNI coordinates I have and the coordinates in the Brainstorm channel file, I am unable to directly overwrite the coordinate data. What should I do to enable Brainstorm to read the MNI coordinates of the source and detector I have? Fig.pdf (243.7 KB)
From the probe positions and the data in the Fig4, these coordinates are defined over a 2D plane (z is constant across all probes). With [0, 0, 0.1] on the front right.
Do you have any information on what is the coordinate system for this file? They are not in MNI space.
Could you share a sample of the files produced by your NIRS device?
Upload the files in your cloud storage site or preference and share the link with us.
Many thanks for your reply. After the collection of my near-infrared device is completed, I can export ".nirs" files and ". hcx" files, and I have uploaded a copy of both. However, during the analysis process using Brainstorm, I only used the ". nirs" file. As you can see, the ".nirs" file collected by my device only contains two-dimensional coordinates, and the device manufacturer said that the three-dimensional coordinates of the probe need to be calculated separately.
So the equipment manufacturer provided me with the coordinates of the probe (prob_sample. CSV) and the coordinates of the reference point (prob_ref. CSV). Based on these two files, I can calculate the MNI coordinates of the probe through software, which is exported in two formats. They are ". mat" (prob_MNI. mat) and ". txt" (prob_MNI. txt), respectively. My current problem is that I cannot import the file with MNI coordinates into Brainstorm.
I have packaged and uploaded all these files to my cloud storage, and here is the link: