Python实现PS图像调整之对比度调整功能示例

# -*- coding: utf-8 -*-
#! python3
import matplotlib.pyplot as plt
from skimage import io
file_name='D:/Visual Effects/PS Algorithm/4.jpg';
img=io.imread(file_name)
img = img * 1.0
thre = img.mean()
# -100 - 100
contrast = -55.0
img_out = img * 1.0
if contrast <= -255.0:
  img_out = (img_out >= 0) + thre -1
elif contrast > -255.0 and contrast < 0:
  img_out = img + (img - thre) * contrast / 255.0
elif contrast < 255.0 and contrast > 0:
  new_con = 255.0 *255.0 / (256.0-contrast) - 255.0
  img_out = img + (img - thre) * new_con / 255.0
else:
  mask_1 = img > thre
  img_out = mask_1 * 255.0
img_out = img_out / 255.0
# 饱和处理
mask_1 = img_out < 0
mask_2 = img_out > 1
img_out = img_out * (1-mask_1)
img_out = img_out * (1-mask_2) + mask_2
plt.figure()
plt.title('www.jb51.net')
plt.imshow(img/255.0)
plt.axis('off')
plt.figure(2)
plt.title('www.jb51.net')
plt.imshow(img_out)
plt.axis('off')
plt.show()