Make LUT Texture

lut_maker.py

#!/usr/bin/env python
# coding: UTF-8

import cv2
import numpy as np


def make_lut256x16(exportPath):
    ''' 256 x 16 LUT '''
    colors = []
    for y in range(0, 16):
        rows = []
        for x in range(0, 256):
            rows.append([
                (x / 16) * 16,  # blue
                y * 16,  # green
                (x % 16) * 16  # red
            ])
        colors.append(rows)

    image = np.array(colors)
    if exportPath:
        cv2.imwrite(exportPath, image)
    return image


def make_lut1024x32(exportPath):
    ''' 1024 x 32 LUT '''
    colors = []
    for y in range(0, 32):
        rows = []
        for x in range(0, 1024):
            rows.append([
                (x / 32) * 8,  # blue
                y * 8,  # green
                (x % 32) * 8  # red
            ])
        colors.append(rows)

    image = np.array(colors)
    if exportPath:
        cv2.imwrite(exportPath, image)
    return image


def make_lut512x512(exportPath):
    ''' 512 x 512 Basic LUT '''
    colors = []
    for y in range(0, 512):
        rows = []
        for x in range(0, 512):
            i = (x % 64, y % 64)
            rows.append([  # BGR
                (y / 2 + x / 16),  # blue
                i[1] * 4,  # green
                i[0] * 4  # red
            ])
        colors.append(rows)

    image = np.array(colors)
    if exportPath:
        cv2.imwrite(exportPath, image)
    return image


if __name__ == '__main__':
    import argparse
    import sys
    parser = argparse.ArgumentParser(description='LUT Texture maker')
    parser.add_argument('path',
                        type=str,
                        nargs='?',
                        default='lut.png',
                        help='output filename')
    parser.add_argument('-s', '--size',
                        type=str,
                        nargs='?',
                        default='512x512',
                        help='256x16 or 1024x32 or 512x512')
    args = parser.parse_args()
    if args.size == '512x512':
        make_lut512x512(args.path)
    elif args.size == '256x16':
        make_lut256x16(args.path)
    elif args.size == '1024x32':
        make_lut1024x32(args.path)
    else:
        sys.exit('Unsupported size')

requirements.txt

cv2
numpy

USAGE

./lut_maker.py lut.png

./lut_maker.py lut512x512.png --size 512x512
./lut_maker.py lut256x16.png --size 256x16
./lut_maker.py lut1024x32.png --size 1024x32

Output

LUT 256x16.png

LUT 1024x32.png

LUT 512x512

The colors do not go all the way to 255 (only 240 in case of 256x16), which will lead to slightly desaturated images.

Here is a proposed workaround, which will work with both 256x16, 1024x32 and also 4096x64 - though not 64 arranged in a 512x512:

samples = 16  # int, 16, 32 or 64
s = float(samples)
mult = 255.0 / (s - 1)

colors = []

for y in range(0, samples):
        rows = []
        for x in range(0, samples * samples):
            rows.append([
                int(round((x / samples) * mult)),  # blue
                int(round(y * mult)),  # green
                int(round((x % samples) * mult))  # red
                ])
        colors.append(rows)

requirements.txt

cv2 numpy

USAGE

./lut_maker.py lut.png

./lut_maker.py lut512x512.png --size 512x512
./lut_maker.py lut256x16.png --size 256x16
./lut_maker.py lut1024x32.png --size 1024x32

Output

LUT 256x16.png

LUT 1024x32.png

LUT 512x512

./lut_maker.py lut.png

./lut_maker.py lut512x512.png --size 512x512
./lut_maker.py lut256x16.png --size 256x16
./lut_maker.py lut1024x32.png --size 1024x32

#!/usr/bin/env python

coding: UTF-8

import cv2
import numpy as np

def make_lut256x16(exportPath):
''' 256 x 16 LUT '''
colors = []
for y in range(0, 16):
rows = []
for x in range(0, 256):
rows.append([
(x / 16) * 16, # blue
y * 16, # green
(x % 16) * 16 # red
])
colors.append(rows)

image = np.array(colors)
if exportPath:
    cv2.imwrite(exportPath, image)
return image

def make_lut1024x32(exportPath):
''' 1024 x 32 LUT '''
colors = []
for y in range(0, 32):
rows = []
for x in range(0, 1024):
rows.append([
(x / 32) * 8, # blue
y * 8, # green
(x % 32) * 8 # red
])
colors.append(rows)

image = np.array(colors)
if exportPath:
    cv2.imwrite(exportPath, image)
return image

def make_lut512x512(exportPath):
''' 4096 x 4096 Basic LUT '''
colors = []
for y in range(0, 4096):
rows = []
for x in range(0, 4096):
i = (x % 64, y % 64)
rows.append([ # BGR
(y / 2 + x / 16), # blue
i[1] * 4, # green
i[0] * 4 # red
])
colors.append(rows)

image = np.array(colors)
if exportPath:
    cv2.imwrite(exportPath, image)
return image

if name == 'main':
import argparse
import sys
parser = argparse.ArgumentParser(description='LUT Texture maker')
parser.add_argument('path',
type=str,
nargs='?',
default='lut.png',
help='output filename')
parser.add_argument('-s', '--size',
type=str,
nargs='?',
default='512x512',
help='256x16 or 1024x32 or 512x512')
args = parser.parse_args()
if args.size == '4096x4096':
make_lut4096x4096(args.path)
elif args.size == '256x16':
make_lut256x16(args.path)
elif args.size == '1024x32':
make_lut1024x32(args.path)
else:
sys.exit('Unsupported size')

#!/usr/bin/env python

coding: UTF-8

import cv2
import numpy as np

def make_lut256x16(exportPath):
''' 256 x 16 LUT '''
colors = []
for y in range(0, 16):
rows = []
for x in range(0, 256):
rows.append([
(x / 16) * 16, # blue
y * 16, # green
(x % 16) * 16 # red
])
colors.append(rows)

image = np.array(colors)
if exportPath:
    cv2.imwrite(exportPath, image)
return image

def make_lut1024x32(exportPath):
''' 1024 x 32 LUT '''
colors = []
for y in range(0, 32):
rows = []
for x in range(0, 1024):
rows.append([
(x / 32) * 8, # blue
y * 8, # green
(x % 32) * 8 # red
])
colors.append(rows)

image = np.array(colors)
if exportPath:
    cv2.imwrite(exportPath, image)
return image

def make_lut512x512(exportPath):
''' 512 x 512 Basic LUT '''
colors = []
for y in range(0, 512):
rows = []
for x in range(0, 512):
i = (x % 64, y % 64)
rows.append([ # BGR
(y / 2 + x / 16), # blue
i[1] * 4, # green
i[0] * 4 # red
])
colors.append(rows)

image = np.array(colors)
if exportPath:
    cv2.imwrite(exportPath, image)
return image

if name == 'main':
import argparse
import sys
parser = argparse.ArgumentParser(description='LUT Texture maker')
parser.add_argument('path',
type=str,
nargs='?',
default='lut.png',
help='output filename')
parser.add_argument('-s', '--size',
type=str,
nargs='?',
default='512x512',
help='256x16 or 1024x32 or 512x512')
args = parser.parse_args()
if args.size == '512x512':
make_lut512x512(args.path)
elif args.size == '256x16':
make_lut256x16(args.path)
elif args.size == '1024x32':
make_lut1024x32(args.path)
else:
sys.exit('Unsupported size')

https://gist.github.com/asus4/09b1f5403c63ceab5ae34710cbe2809e#gistcomment-1740811

samples = 16 # int, 16, 32 or 64
s = float(samples)
mult = 255.0 / (s - 1)

colors = []

for y in range(0, samples):
rows = []
for x in range(0, samples * samples):
rows.append([
int(round((x / samples) * mult)), # blue
int(round(y * mult)), # green
int(round((x % samples) * mult)) # red
])
colors.append(rows)

!/usr/bin/env python

coding: UTF-8

import cv2
import numpy as np

def make_lut256x16(exportPath):
''' 256 x 16 LUT '''
colors = []
for y in range(0, 16):
rows = []
for x in range(0, 256):
rows.append([
(x / 16) * 16, # blue
y * 16, # green
(x % 16) * 16 # red
])
colors.append(rows)

image = np.array(colors)
if exportPath:
    cv2.imwrite(exportPath, image)
return image

def make_lut1024x32(exportPath):
''' 1024 x 32 LUT '''
colors = []
for y in range(0, 32):
rows = []
for x in range(0, 1024):
rows.append([
(x / 32) * 8, # blue
y * 8, # green
(x % 32) * 8 # red
])
colors.append(rows)

image = np.array(colors)
if exportPath:
    cv2.imwrite(exportPath, image)
return image

def make_lut512x512(exportPath):
''' 512 x 512 Basic LUT '''
colors = []
for y in range(0, 512):
rows = []
for x in range(0, 512):
i = (x % 64, y % 64)
rows.append([ # BGR
(y / 2 + x / 16), # blue
i[1] * 4, # green
i[0] * 4 # red
])
colors.append(rows)

image = np.array(colors)
if exportPath:
    cv2.imwrite(exportPath, image)
return image

if name == 'main':
import argparse
import sys
parser = argparse.ArgumentParser(description='LUT Texture maker')
parser.add_argument('path',
type=str,
nargs='?',
default='lut.png',
help='output filename')
parser.add_argument('-s', '--size',
type=str,
nargs='?',
default='512x512',
help='256x16 or 1024x32 or 512x512')
args = parser.parse_args()
if args.size == '512x512':
make_lut512x512(args.path)
elif args.size == '256x16':
make_lut256x16(args.path)
elif args.size == '1024x32':
make_lut1024x32(args.path)
else:
sys.exit('Unsupported size')

requirements.txt

cv2 numpy

USAGE

./lut_maker.py lut.png

./lut_maker.py lut4096x4096.png --size 4096x4096
./lut_maker.py lut256x16.png --size 256x16
./lut_maker.py lut1024x32.png --size 1024x32

Output

LUT 256x16.png

LUT 1024x32.png

LUT 4096x4096