python - 获取图像opencv python中每个 channel 的对比度

Question

如何计算图像中每个 channel 的对比度？
由于它们有很多对比定义there

网吧对比

迈克尔逊对比

RMS 对比度

我需要计算这些对比。

Answer 1

from PIL import Image
import numpy as np
from numpy import mean, sqrt, square
im = Image.open("leaf.jpg") # Image file name
pixels = list(im.getdata())
width, height = im.size
pixels = np.asarray([pixels[i * width:(i + 1) * width] for i in range(height)], dtype=int)

ch_1 = pixels[:,:,0]
ch_2 = pixels[:,:,1]
ch_3 = pixels[:,:,2]

rms_of_ch1 = sqrt(mean(square(ch_1)))
rms_of_ch2 = sqrt(mean(square(ch_2)))
rms_of_ch3 = sqrt(mean(square(ch_3)))