st2xyzt: st2xyzt

In AnalyzeFMRI: Functions for Analysis of fMRI Datasets Stored in the ANALYZE or NIFTI Format

Description

Encode and assemble a space code with a time code dimension into the combined one byte xyzt.units field of a NIFTI header file.

Usage

st2xyzt(space,time)

Arguments

space	space field of a NIFTI file
time	time field of a NIFTI file

Value

A list containing xyzt.units field.

Bits 0..2 of xyzt.units specify the units of pixdim[2..4] (e.g., spatial units are values 0,1,2,...,7). Bits 3..5 of xyzt.units specify the units of pixdim[5] (e.g., temporal units are multiples of 8: 0,8,16,24,32,40,48,56).

This compression of 2 distinct concepts into 1 byte is due to the limited space available in the 348 byte ANALYZE 7.5 header.

Some NIFTI codes: 0 (unspecified units), 1 (meters), 2 (millimeters), 3 (micrometers), 8 (seconds), 16 (milliseconds), 24 (microseconds), 32 (Hertz), 40 (ppm, part per million) and 48 (radians per second).

See Also

xyzt2st

Examples

xyzt.units <- f.read.header(system.file("example-nifti.hdr", package="AnalyzeFMRI"))$xyzt.units
mylist <- xyzt2st(xyzt.units)
st2xyzt(mylist$space,mylist$time)

AnalyzeFMRI documentation built on Oct. 5, 2021, 5:06 p.m.