SIQ: Super-Resolution Image Quantification

SIQ is a powerful and flexible Python library for deep learning-based image super-resolution, with a focus on medical imaging applications. It provides a comprehensive toolkit for every stage of the super-resolution workflow, from data generation and model training to robust inference and evaluation.

The library is built on TensorFlow/Keras and ANTSpy and is designed to handle complex, real-world challenges such as anisotropic super-resolution (where different upsampling factors are needed for each axis) and multi-task learning (e.g., simultaneously upsampling an image and its segmentation mask).

Function-specific documentation is here.

Key Features

SIQ is more than just an inference tool; it's a complete framework that facilitates:

• Flexible Data Generation: Automatically create paired low-resolution and high-resolution patches for training with siq.image_generator. Includes support for multi-channel data (e.g., image + segmentation) via siq.seg_generator.
• Advanced Model Architectures: Easily instantiate powerful Deep Back-Projection Networks (DBPN) for 2D and 3D with siq.default_dbpn, customized for any upsampling factor and multi-task outputs.
• Perceptual Loss Training: Go beyond simple Mean Squared Error. SIQ includes tools for using pre-trained feature extractors (siq.get_grader_feature_network, siq.pseudo_3d_vgg_features_unbiased) to optimize for perceptual quality.
• Intelligent Loss Weighting: Automatically balance complex, multi-component loss functions (e.g., MSE + Perceptual + Dice) with a single command (siq.auto_weight_loss, siq.auto_weight_loss_seg) to ensure stable training.
• End-to-End Training Pipelines: Train models from start to finish with the high-level siq.train and siq.train_seg functions, which handle data generation, validation, and model saving.
• Robust Inference: Apply your trained models to new images with siq.inference, including specialized logic for region-wise and blended super-resolution when guided by a segmentation mask.
• Comprehensive Evaluation: Systematically benchmark and compare model performance with siq.compare_models, which calculates PSNR, SSIM, and Dice metrics against baseline methods.

Installation

You can install the official release directly from PyPI:

bash pip install siq

To install the latest development version from this repository:

bash git clone https://github.com/stnava/siq.git cd siq pip install .

Quick Start: A 5-Minute Example

The examples demonstrate the core workflow: training a model on publicly available data and using it for inference.

bash tests/test.py tests/test_seg.py

Pre-trained Models and Compatibility

We provide a collection of pre-trained models to get you started without requiring you to train from scratch.

• Download Pre-trained Models from Figshare

Important Note on Keras/TensorFlow Versions

The deep learning ecosystem evolves quickly. Models saved with older versions of TensorFlow/Keras (as .h5 files) may have trouble loading in newer versions (TF >= 2.16) due to the transition to the .keras format.

If you encounter issues loading a legacy .h5 model, we provide a robust conversion script. This utility will convert your old .h5 files into the modern .keras format.

Usage:

```python import siq

Define the directory containing your old .h5 models

sourcedir = "~/.antspymm/" # Or wherever you downloaded the models outputdir = "./convertedkerasmodels"

Convert the models

siq.converth5tokerasformat( searchdirectory=sourcedir, outputdirectory=outputdir, exclude_patterns=["*weights.h5"] # Skips files that are just weights ) ```

After running this, you can load the converted models from the converted_keras_models directory using siq.read_srmodel or tf.keras.models.load_model.

For Developers

Setting Up the Environment

This package is tested with Python 3.11 and TensorFlow 2.17. For optimal CPU performance, especially on Linux, you may want to set these environment variables:

bash export TF_ENABLE_ONEDNN_OPTS=1 export ITK_GLOBAL_DEFAULT_NUMBER_OF_THREADS=8 export TF_NUM_INTRAOP_THREADS=8 export TF_NUM_INTEROP_THREADS=8

Publishing a New Release

To publish a new version of siq to PyPI:

```bash

Ensure build and twine are installed

python3 -m pip install build twine

Clean previous builds

rm -rf build/ siq.egg-info/ dist/

Build the package

python3 -m build .

Upload to PyPI

python3 -m twine upload --repository siq dist/* ```