qmricolors 0.1.2

A Python package for easy access to the lipari and navia colormaps for quantitative MRI visualization.

qMRI Colors

A Python package providing the recommended colormaps from Fuderer et al. (2024) for quantitative MRI visualization. This package makes it easy to use the scientifically-optimized lipari and navia colormaps in both matplotlib and vispy, eliminating the need for manual colormap registration in each project.

The colormaps are based on the research presented in "Colormaps for quantitative magnetic resonance imaging" (Magnetic Resonance in Medicine, 2024) and are sourced from the colorResources repository.

WARNING At the moment this package does not comply with the recommendations because it's not adapting to the underlying image, see https://magneticresonanceimaging.github.io/QMRIColors.jl/dev/clip/ for an explanation.

Installation

Install the package using uv (recommended) or pip:

# Using uv
uv add qmricolors

# Using pip
pip install qmricolors

For development:

git clone [e-mail]:oscarvanderheide/qmricolors.git
cd qmricolors
uv sync

# Install in development mode to use examples
uv pip install -e .

Usage

Simply import the package to automatically register the custom colormaps:

import qmricolors

Matplotlib Usage

import matplotlib.pyplot as plt
import numpy as np
import qmricolors

# Create sample data
data = np.random.rand(100, 100)

# Use the custom colormaps
plt.figure(figsize=(12, 5))

plt.subplot(1, 2, 1)
plt.imshow(data, cmap='lipari')
plt.title('Lipari Colormap')
plt.colorbar()

plt.subplot(1, 2, 2)
plt.imshow(data, cmap='navia')
plt.title('Navia Colormap')
plt.colorbar()

plt.show()

VisPy Usage

from vispy import app, scene
from vispy.color import get_colormap
import numpy as np
import qmricolors

# Create sample data
data = np.random.rand(100, 100)

# Get custom colormap
lipari_cmap = get_colormap('lipari')

# Create visualization
canvas = scene.SceneCanvas(keys='interactive', show=True)
view = canvas.central_widget.add_view()
image = scene.visuals.Image(data, cmap=lipari_cmap, parent=view.scene)
view.camera = scene.PanZoomCamera(aspect=1)
view.camera.set_range()

app.run()

Note: If the VisPy window doesn't appear, this may be due to GUI backend issues. Try:

1. Installing a GUI backend: pip install PyQt5 or pip install PySide2
2. On macOS, you may need to run Python from the terminal rather than an IDE
3. Use the simple test script: python test_vispy_simple.py

Direct API Usage

import qmricolors

# Get colormap for specific backend
lipari_mpl = qmricolors.get_colormap('lipari', backend='matplotlib')
navia_vispy = qmricolors.get_colormap('navia', backend='vispy')

# List available colormaps
print(qmricolors.AVAILABLE_CMAPS)  # ['lipari', 'navia']

# Register colormaps manually (if needed)
qmricolors.register_all_colormaps()

Available Colormaps

• lipari: A scientifically-optimized colormap for quantitative MRI visualization
• navia: A scientifically-optimized colormap for quantitative MRI visualization

These colormaps were designed based on perceptual uniformity principles and extensive testing for quantitative medical imaging, as described in Fuderer et al. (2024).

Customizing Colormaps

To use your own colormap data, replace the CSV files in the package:

1. qmricolors/lipari.csv
2. qmricolors/navia.csv

The CSV format should contain space-separated RGB values (without headers), with values between 0 and 1:

0.011370 0.073240 0.148284
0.013965 0.079062 0.155370
0.015899 0.084718 0.162521
0.017234 0.090035 0.169728
...

Each line represents one color with three space-separated values for red, green, and blue components.

Examples

The package includes several example scripts to demonstrate usage:

General Example

Test basic colormap functionality:

uv run qmricolors/examples/example.py

Matplotlib Example

See matplotlib-specific plotting examples:

uv run qmricolors/examples/matplotlib_example.py

VisPy Example

Interactive 3D visualization with VisPy (requires GUI):

uv run qmricolors/examples/vispy_example.py

Dependencies

• matplotlib >= 3.10.3
• vispy >= 0.15.2
• numpy >= 1.21.0

References

• Fuderer, M., et al. (2024). Colormaps for quantitative magnetic resonance imaging. Magnetic Resonance in Medicine. https://pubmed.ncbi.nlm.nih.gov/39415361/
• Original colormap resources: https://github.com/mfuderer/colorResources

License

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Contributing

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