NrrdLoader

class io.loaders.NrrdLoader

Bases: io.loaders.BaseImageLoader

NRRDLOADER - Loader for NRRD (Nearly Raw Raster Data) files, based on.

io.loaders.BaseImageLoader base class

Constructor Summary
NrrdLoader(options)

NRRDLOADER - Constructor for NrrdLoader class.

Syntax:
loader = io.loaders.NrrdLoader(options)
Input Arguments:

  • options - (optional) struct with fields:

    • waitbar - [logical] show or not the waitbar; default: false

    • mibPath - [char] path to MIB directory

    • customSections - [logical] load custom sections only; default: false

    • customSectionsSettings - [struct] custom section parameters

    • imgStretch - [logical] stretch uint32 images to uint16; default: false

    • silentMode - [logical] do not ask user questions; default: false

    • verbose - [logical] show timing information; default: false

    • Font - [struct] font settings for dialogs

    • ParentFigure - handle of the main MIB window (parent for uiprogressdlg)

Output Arguments:

  • obj - instance of the NrrdLoader class

Example 1 - create loader with options:

options.waitbar = true;
loader = io.loaders.NrrdLoader(options);
Method Summary
loadImages(files, imginfo, options)

LOADIMAGES - Load image data from NRRD files.

Syntax:
[img, imginfo] = obj.loadImages(files, imginfo, options)

This method loads actual image data. It uses nrrdLoadWithMetadata (Linux/Win) or nhdr_nrrd_read (Mac) and handles dimension permutation.

Input Arguments:

  • files - structure array from loadMetadata

  • imginfo - dictionary from loadMetadata

  • options - (optional) struct for image loading

Output Arguments:

  • img - loaded image dataset

  • imginfo - updated dictionary

Example 1 - load images from NRRD file:

loader = io.loaders.NrrdLoader();
[imginfo, files] = loader.loadMetadata({'dataset.nrrd'}, options);
[img, imginfo] = loader.loadImages(files, imginfo, options);
loadMetadata(filenames, options)

LOADMETADATA - Load metadata for NRRD files.

Syntax:
[imginfo, files] = obj.loadMetadata(filenames, options)

This method parses NRRD headers to extract dataset metadata. It handles voxel sizes, space directions, and dimension ordering.

Input Arguments:

  • filenames - cell array with filenames of NRRD files

  • options - (optional) struct with fields:

    • waitbar - [logical] show or not the waitbar; default: false

    • customSections - [logical] load part of the dataset; default: false

    • Font - [struct] font settings for dialogs

Output Arguments:

  • imginfo - dictionary with image metadata containing fields:

    • Height - image height in pixels

    • Width - image width in pixels

    • Colors - number of color channels

    • Depth - number of z-slices

    • Time - number of time points

    • imgClass - image class (uint8, uint16, etc.)

    • ColorType - 'grayscale', 'truecolor', or 'indexed'

    • ImageDescription - description with BoundingBox info

    • Format - HDF5 format type ('matlab.hdf5' or 'bdv.hdf5')

    • Levels - number of pyramid levels (for BDV only)

    • ReturnedLevel - selected pyramid level (for BDV only)

    • pixSize - struct with pixel sizes: .x, .y, .z, .t, .units, .tunits

    • other format-specific metadata fields

  • files - structure array with file information

Example 1 - load metadata from NRRD file:

loader = io.loaders.NrrdLoader();
filenames = {'dataset.nrrd'};
[imginfo, files] = loader.loadMetadata(filenames, options);