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|
# SPDX-License-Identifier: BSD-2-Clause
#
# Copyright (C) 2019, Raspberry Pi Ltd
#
# ctt_ccm.py - camera tuning tool for CCM (colour correction matrix)
from ctt_image_load import *
from ctt_awb import get_alsc_patches
import colors
from scipy.optimize import minimize
from ctt_visualise import visualise_macbeth_chart
import numpy as np
"""
takes 8-bit macbeth chart values, degammas and returns 16 bit
"""
'''
This program has many options from which to derive the color matrix from.
The first is average. This minimises the average delta E across all patches of
the macbeth chart. Testing across all cameras yeilded this as the most color
accurate and vivid. Other options are avalible however.
Maximum minimises the maximum Delta E of the patches. It iterates through till
a minimum maximum is found (so that there is
not one patch that deviates wildly.)
This yields generally good results but overall the colors are less accurate
Have a fiddle with maximum and see what you think.
The final option allows you to select the patches for which to average across.
This means that you can bias certain patches, for instance if you want the
reds to be more accurate.
'''
matrix_selection_types = ["average", "maximum", "patches"]
typenum = 0 # select from array above, 0 = average, 1 = maximum, 2 = patches
test_patches = [1, 2, 5, 8, 9, 12, 14]
'''
Enter patches to test for. Can also be entered twice if you
would like twice as much bias on one patch.
'''
def degamma(x):
x = x / ((2 ** 8) - 1) # takes 255 and scales it down to one
x = np.where(x < 0.04045, x / 12.92, ((x + 0.055) / 1.055) ** 2.4)
x = x * ((2 ** 16) - 1) # takes one and scales up to 65535, 16 bit color
return x
def gamma(x):
# Take 3 long array of color values and gamma them
return [((colour / 255) ** (1 / 2.4) * 1.055 - 0.055) * 255 for colour in x]
"""
FInds colour correction matrices for list of images
"""
def ccm(Cam, cal_cr_list, cal_cb_list):
global matrix_selection_types, typenum
imgs = Cam.imgs
"""
standard macbeth chart colour values
"""
m_rgb = np.array([ # these are in RGB
[116, 81, 67], # dark skin
[199, 147, 129], # light skin
[91, 122, 156], # blue sky
[90, 108, 64], # foliage
[130, 128, 176], # blue flower
[92, 190, 172], # bluish green
[224, 124, 47], # orange
[68, 91, 170], # purplish blue
[198, 82, 97], # moderate red
[94, 58, 106], # purple
[159, 189, 63], # yellow green
[230, 162, 39], # orange yellow
[35, 63, 147], # blue
[67, 149, 74], # green
[180, 49, 57], # red
[238, 198, 20], # yellow
[193, 84, 151], # magenta
[0, 136, 170], # cyan (goes out of gamut)
[245, 245, 243], # white 9.5
[200, 202, 202], # neutral 8
[161, 163, 163], # neutral 6.5
[121, 121, 122], # neutral 5
[82, 84, 86], # neutral 3.5
[49, 49, 51] # black 2
])
"""
convert reference colours from srgb to rgb
"""
m_srgb = degamma(m_rgb) # now in 16 bit color.
# Produce array of LAB values for ideal color chart
m_lab = [colors.RGB_to_LAB(color / 256) for color in m_srgb]
"""
reorder reference values to match how patches are ordered
"""
m_srgb = np.array([m_srgb[i::6] for i in range(6)]).reshape((24, 3))
m_lab = np.array([m_lab[i::6] for i in range(6)]).reshape((24, 3))
m_rgb = np.array([m_rgb[i::6] for i in range(6)]).reshape((24, 3))
"""
reformat alsc correction tables or set colour_cals to None if alsc is
deactivated
"""
if cal_cr_list is None:
colour_cals = None
else:
colour_cals = {}
for cr, cb in zip(cal_cr_list, cal_cb_list):
cr_tab = cr['table']
cb_tab = cb['table']
"""
normalise tables so min value is 1
"""
cr_tab = cr_tab / np.min(cr_tab)
cb_tab = cb_tab / np.min(cb_tab)
colour_cals[cr['ct']] = [cr_tab, cb_tab]
"""
for each image, perform awb and alsc corrections.
Then calculate the colour correction matrix for that image, recording the
ccm and the colour tempertaure.
"""
ccm_tab = {}
for Img in imgs:
Cam.log += '\nProcessing image: ' + Img.name
"""
get macbeth patches with alsc applied if alsc enabled.
Note: if alsc is disabled then colour_cals will be set to None and no
the function will simply return the macbeth patches
"""
r, b, g = get_alsc_patches(Img, colour_cals, grey=False)
# 256 values for each patch of sRGB values
"""
|
