Colour correction using a color checker

color_correction.py

# This example based on the following tutorial
# https://github.com/colour-science/colour-checker-detection/blob/master/colour_checker_detection/examples/examples_detection.ipynb

import matplotlib.pyplot as plt
import numpy as np
import streamlit as st

import colour

from colour_checker_detection import detect_colour_checkers_segmentation
from colour_checker_detection.detection.segmentation import adjust_image


def show(img, st):
    st.image(np.clip(colour.cctf_encoding(img), 0, 1))


def do1(img_name, st):
    st.markdown("## " + img_name)

    img = colour.io.read_image(img_name)
    img = colour.cctf_decoding(img)
    show(img, st)

    swatches1, *_ = detect_colour_checkers_segmentation(img)

    D65 = colour.CCS_ILLUMINANTS["CIE 1931 2 Degree Standard Observer"]["D65"]
    CC = colour.CCS_COLOURCHECKERS["cca2014"]

    swatches_ref = colour.XYZ_to_RGB(
        colour.xyY_to_XYZ(list(CC.data.values())),
        CC.illuminant,
        colour.RGB_COLOURSPACES["sRGB"].whitepoint,
        colour.RGB_COLOURSPACES["sRGB"].matrix_XYZ_to_RGB,
    )

    def plot_vs_ref(swatches):
        swatches_XYZ = colour.RGB_to_XYZ(swatches, D65, D65, colour.RGB_COLOURSPACES["sRGB"].matrix_RGB_to_XYZ)
        swatches_xyY = colour.XYZ_to_xyY(swatches_XYZ)
        cc1 = colour.characterisation.ColourChecker(img_name, dict(zip(CC.data.keys(), swatches_xyY)), D65)
        fig, _ = colour.plotting.plot_multi_colour_checkers([CC, cc1])
        st.pyplot(fig)


    plot_vs_ref(swatches1)

    swatches2 = colour.colour_correction(swatches1, swatches1, swatches_ref)
    plot_vs_ref(swatches2)

    st.markdown("---")


# wget https://doneata.bitbucket.io/static/PXL_20220930_084436202.{dng,jpg}
# dcraw -g 2.4 12.92 PXL_20220930_084436202.dng

st.set_page_config(layout="wide")
cols = st.columns(2)
do1("PXL_20220930_084436202.jpg", cols[0])
do1("PXL_20220930_084436202.ppm", cols[1])