Read metadata from NRRD file
Read Metadata from NRRD File
Read the metadata from an NRRD format file. The file is part of a data set containing the 3-D CT and MRI scans from The Retrospective Image Registration Evaluation (RIRE) Dataset, converted to the NRRD file format. The original data set was provided by Dr. Michael Fitzpatrick. For more information, see the RIRE Project homepage. The size of the entire data set is approximately 35 MB. Download the data set from the MathWorks® website, then unzip the folder.
zipFile = matlab.internal.examples.downloadSupportFile("medical", ... "MedicalRegistrationNRRDdata.zip"); filepath = fileparts(zipFile); unzip(zipFile,filepath)
Specify the name of the NRRD file to read.
filename = fullfile(filepath,"supportfilesNRRD","Patient007CT.nrrd");
Read the metadata from
info = nrrdinfo(filename);
ImageSize metadata field contains the image volume size, in pixels.
ans = 1×3 512 512 28
PixelDimensions metadata field contains the voxel size in each dimension, in real world units such as millimeters.
ans = 1×3 0.6536 0.6536 4.0000
SpatialMapping metadata field contains an
affinetform3d object that defines the transformation between the intrinsic and patient coordinate systems for the volume.
ans = affinetform3d with properties: Dimensionality: 3 A: [4×4 double]
RawAttributes metadata field contains the raw metadata extracted from the NRRD header information.
ans = struct with fields: dimension: '3' sizes: '512 512 28 ' type: 'float' encoding: 'raw' endian: 'little' spacedimension: '3' spaceorigin: '(1.653595, 1.653595, 5.000000)' spacedirections: '(0.653595,0.000000,0.000000) (0.000000,0.653595,0.000000) (0.000000,0.000000,4.000000)'
filename — Name of NRRD file
string scalar | character vector
Name of the NRRD file, specified as a string scalar or a character vector. The file
must contain a valid NRRD file header. The
supports NRRD files containing header and image data (
.nrrd) as well
as detached header files (
filenameas the absolute path to the file, a relative path from
the current directory, or a relative path from a directory on the MATLAB® path.
info — NRRD metadata
NRRD metadata, returned as a structure.
Introduced in R2022b