Python/digital_image_processing/sepia.py
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Python

"""
Implemented an algorithm using opencv to tone an image with sepia technique
"""
from cv2 import destroyAllWindows, imread, imshow, waitKey
def make_sepia(img, factor: int):
"""
Function create sepia tone.
Source: https://en.wikipedia.org/wiki/Sepia_(color)
"""
pixel_h, pixel_v = img.shape[0], img.shape[1]
def to_grayscale(blue, green, red):
"""
Helper function to create pixel's greyscale representation
Src: https://pl.wikipedia.org/wiki/YUV
"""
return 0.2126 * red + 0.587 * green + 0.114 * blue
def normalize(value):
"""Helper function to normalize R/G/B value -> return 255 if value > 255"""
return min(value, 255)
for i in range(pixel_h):
for j in range(pixel_v):
greyscale = int(to_grayscale(*img[i][j]))
img[i][j] = [
normalize(greyscale),
normalize(greyscale + factor),
normalize(greyscale + 2 * factor),
]
return img
if __name__ == "__main__":
# read original image
images = {
percentage: imread("image_data/lena.jpg", 1) for percentage in (10, 20, 30, 40)
}
for percentage, img in images.items():
make_sepia(img, percentage)
for percentage, img in images.items():
imshow(f"Original image with sepia (factor: {percentage})", img)
waitKey(0)
destroyAllWindows()