Determine the header and data file of an ANALYZE 7.5 or NIFTI v1 pair file.

The two formats ANALYZE 7.5 and NIFTI v1 (in its two-file variant) store the image in a header file (<base>.hdr) and a data file (<base>.img). This function computes the two file names from any of them, so that the user can pass any of the possible spellings.

Usage

analyze.pair.files(filepath, require_header = FALSE)

Arguments

filepath

character string, the path to the header file, to the data file, or to the base name (with or without a .hdr/.img/.gz suffix).

require_header

logical, whether to stop with an error if the header file does not exist. If FALSE, the computed file names are returned even if the files are missing.

Value

named list with the entries header and image, the full paths to the header and the data file, the logical entries header_exists and image_exists, and the entries mat (the path of the MATLAB sidecar file that SPM and FreeSurfer write next to the image file, see read.fs.volume.analyze) and mat_exists, which report whether such a file is present.

Note

Compression is handled the way the other implementations of the format handle it: the suffix .gz (and .hdr/.img) is stripped from the file name to get the base name, and the two file names are constructed from it. A name like vol.hdr.gz therefore describes the pair vol.hdr.gz and vol.img.gz, and vol.nii.gz would be the pair vol.nii.hdr.gz and vol.nii.img.gz. Note that many tools only read uncompressed pairs, so compressed pairs should only be written if the software that reads them supports this.