Simple python demos of Automatic Color Palette Selection [Chang et al. 2015].

They proposed palette-based photo recoloring method for image editing.

I will implement automatic color palette selection part for single and multi-images.

This package includes:

• ColorPixels class: palette/core/color_pixels.py.
  • Compute RGB, Lab, HSV color pixels from image.
• Hist3D class: palette/core/hist_3d.py.
  • Compute 3D color histogram for the target color space.
• PaletteSelection class: palette/core/palette_selection.py.
  • Select palette colors from Hist3D output.

from palette.io_util.image import loadRGB
from palette.core.hist_3d import Hist3D
from palette.core.palette_selection import PaletteSelection
import matplotlib.pyplot as plt

# Load image.
image = loadRGB(image_file)

# 16 bins, Lab color space
hist3D = Hist3D(image, num_bins=16, color_space='Lab')

color_coordinates = hist3D.colorCoordinates()
color_densities = hist3D.colorDensities()
rgb_colors = hist3D.rgbColors()

# 5 colors from Lab color samples.
palette_selection = PaletteSelection(color_coordinates,
                                             color_densities, rgb_colors,
                                             num_colors=5, sigma=70.0)

fig = plt.figure()

# Plot image.
fig.add_subplot(131)
plt.imshow(image)
plt.axis('off')

# Plot palette colors.
fig.add_subplot(132)
palette_selection.plot(plt)
plt.axis('off')

# Plot 3D color histogram.
ax = fig.add_subplot(133, projection='3d')
hist3D.plot(ax)

plt.show()

In the following demo, I compare the palette selection results by changing color_space.

In the following demo, I test the palette selection for multi-images.

Note: This program was only tested on Windows with Python2.7. Linux and Mac OS are not officially supported, but the following instructions might be helpful for installing on those environments.

Please install the following required python modules.

• NumPy
• SciPy
• matplotlib
• OpenCV

As these modules are heavily dependent on NumPy modules, please install appropriate packages for your development environment (Python versions, 32-bit or 64-bit). For 64-bit Windows, you can download the binaries from Unofficial Windows Binaries for Python Extension Packages.

You can use pip command for installing main modules. Please run the following command from the shell.

  > pip install git+https://github.com/tody411/PaletteSelection.git

• palette/main.py:

You can test the Palette Selection with the following command from palette directory.

  > python main.py

This command will start downloading test images via Google Image API then run the demo module to generate result images.

• palette/examples: You can find minimal example codes.
• palette/results: You can also find example codes to generate result images.

The MIT License 2015 (c) tody