NIfTI Data Loader Operator

Authors: Holoscan SDK Team (NVIDIA)
Supported platforms: x86_64, aarch64
Language: Python
Last modified: June 2, 2025
Latest version: 1.1.0
Minimum Holoscan SDK version: 1.0.3
Tested Holoscan SDK versions: 2.2.0, 3.2.0
Contribution metric: Level 2 - Trusted

This operator loads NIfTI (nii/nii.gz) medical images for use in Holoscan pipelines.

Overview

The NIIDataLoaderOperator reads NIfTI files and makes them available as in-memory images for downstream processing in medical imaging workflows.

Requirements

• Holoscan SDK Python package (version >= 1.0.3)
• SimpleITK
• numpy

Example Usage

from pathlib import Path
from holoscan.core import Fragment
from operators.medical_imaging.nii_data_loader_operator import NiftiDataLoader

# Create a fragment
fragment = Fragment()

# Initialize the NIfTI loader with a path to your NIfTI file
nii_path = Path("path/to/your/image.nii")  # or .nii.gz
nii_loader = NiftiDataLoader(fragment, input_path=nii_path)

# The operator can be used in a pipeline
# The output port 'image' will contain the loaded image as a numpy array
# You can connect it to other operators that expect image data

Input/Output Ports

• Input:
• image_path (optional): Path to the NIfTI file. If not provided, uses the path specified during initialization.
• Output:
• image: Numpy array containing the loaded image data.

Notes

• The operator supports both .nii and .nii.gz file formats
• The output image is transposed to match the expected orientation (axes order: [2, 1, 0])