change contrast Algorithm
In visual perception of the real universe, contrast is determined by the difference in the color and brightness of the object and other objects within the same field of view. The human visual system is more sensitive to contrast than absolute luminance; we can perceive the universe similarly regardless of the huge changes in illumination over the day or from place to place.
"""
Changing contrast with PIL
This algorithm is used in
https://noivce.pythonanywhere.com/ Python web app.
python/black: True
flake8 : True
"""
from PIL import Image
def change_contrast(img: Image, level: float) -> Image:
"""
Function to change contrast
"""
factor = (259 * (level + 255)) / (255 * (259 - level))
def contrast(c: int) -> float:
"""
Fundamental Transformation/Operation that'll be performed on
every bit.
"""
return 128 + factor * (c - 128)
return img.point(contrast)
if __name__ == "__main__":
# Load image
with Image.open("image_data/lena.jpg") as img:
# Change contrast to 170
cont_img = change_contrast(img, 170)
cont_img.save("image_data/lena_high_contrast.png", format="png")
