Supported File formats¶

Introduction¶

There are a number of different manufacturers and custom OPM systems in operation across the world. As such, there are also a number of different file formats out there. SPM supports the following formats.

UCL¶

When initially developing our in-house OPM system there were no file-formats. The data acquisition system was written from scratch and we had to think of how to store the data. We settled on the raw data being stored in a binary file and all the metadata stored in TSV and JSON files. This was designed to be as aligned as possible to the BIDS file structure and to reinvent as few wheels as possible. All the metadata files are described in the BIDS standard

S =[];
S.data = 'meg.bin';
S.coordystem='coordsystem.json';
S.channels='channels.tsv';
S.meg='meg.json';
S.positions = 'positions.tsv'
D = spm_opm_create(S);

Alternatively, if all the relevant metadata is in the same folder as the binary file and follows the BIDS naming standard you only need to specify the binary file as an argument.

S =[];
S.data = 'meg.bin';
D = spm_opm_create(S);

Cerca Magnetics¶

Cerca Magnetics offers a very similar format to the UCL format, with a simple binary file to store the data and the metadata stored in text files.

S = [];
S.data ='OPM_meg_001.cMEG';
S.positions= 'OPM_HelmConfig.tsv';
D = spm_opm_create(S);

Fieldline¶

Fieldline uses the existing .fif format and can take advantage of existing fileio available in SPM. Additionally, the SPM function spm_opm_create can overwrite the sensor positions in the file if you supply it with a positions.tsv file. This is optional. If you do not provide this file the function will use the default sensor positions in the file.

S = [];
S.data = 'raw.fif';
D =spm_opm_create(S);

If you wish to overwrite the positions in the file the code below should work.

S = [];
S.data = 'raw.fif';
S.positions = 'positions.tsv';
D =spm_opm_create(S);

Neuro-1¶

The Neuro-1 system developed by QuSpin currently records data in .lvm files. just as with the other data files we can provide additional metadata in the form of .tsv and .json files

S = [];
S.data ='Array 1.lvm';
S.positions= 'Array 1_positions.tsv';
D = spm_opm_create(S);