34 lines
1.1 KiB
Python
34 lines
1.1 KiB
Python
"""Precompute CAM16-UCS colour tuples for all 2^24 RGB tuples.
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This 192MB data file is used to convert from RGB to CAM16-UCS colour space
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for purposes of computing (approximate) perceptual difference between pairs of
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colours when optimizing the image conversion (since this perceptual
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difference corresponds to the Euclidean distance in this colour space)
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"""
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import colour
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import numpy as np
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def main():
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print("Precomputing conversion matrix from RGB to CAM16UCS colour space")
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# Compute matrix of all 24-bit RGB values, normalized to 0..1 range
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bits24 = np.arange(2 ** 24, dtype=np.uint32).reshape(-1, 1)
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all_rgb = np.concatenate(
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[bits24 >> 16 & 0xff, bits24 >> 8 & 0xff, bits24 & 0xff],
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axis=1).astype(np.float32) / 255
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del bits24
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with colour.utilities.suppress_warnings(colour_usage_warnings=True):
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# Compute matrix of corresponding CAM16UCS colour values, indexed
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# by 24-bit RGB value
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all_cam16 = colour.convert(all_rgb, "RGB", "CAM16UCS").astype(
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np.float32)
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del all_rgb
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np.save("data/rgb_to_cam16ucs.npy", all_cam16)
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if __name__ == "__main__":
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main()
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