Python实现PS图像调整颜色梯度效果示例

程序员文章站 2023-01-13 10:58:20

本文实例讲述了Python实现PS图像调整颜色梯度效果。分享给大家供大家参考，具体如下：这里用 Python 实现 PS 中的色彩图，可以看到颜色的各种渐变，具体的效果...

本文实例讲述了Python实现PS图像调整颜色梯度效果。分享给大家供大家参考，具体如下：

这里用 Python 实现 PS 中的色彩图，可以看到颜色的各种渐变，具体的效果可以参考附录说明

和之前的程序相比，这里利用矩阵的运算替代了 for 循环，提升了运行的效率。

import numpy as np
import matplotlib.pyplot as plt
from skimage import io
import numpy.matlib
from skimage import img_as_float
file_name='D:/Visual Effects/PS Algorithm/4.jpg';
img=io.imread(file_name)
img = img_as_float(img)
row, col, channel = img.shape
rNW = 0.5
rNE = 1.0
rSW = 1.0
rSE = 0.0
gNW = 0.0
gNE = 0.5
gSW = 0.0
gSE = 1.0
bNW = 1.0
bNE = 0.0
bSW = 1.0
bSE = 0.0
xx = np.arange (col)
yy = np.arange (row)
x_mask = numpy.matlib.repmat (xx, row, 1)
y_mask = numpy.matlib.repmat (yy, col, 1)
y_mask = np.transpose(y_mask)
fx = x_mask * 1.0 / col
fy = y_mask * 1.0 / row
p = rNW + (rNE - rNW) * fx
q = rSW + (rSE - rSW) * fx
r = ( p + (q - p) * fy )
r[r<0] = 0
r[r>1] =1
p = gNW + (gNE - gNW) * fx
q = gSW + (gSE - gSW) * fx
g = ( p + (q - p) * fy )
g[g<0] = 0
g[g>1] =1
p = bNW + (bNE - bNW) * fx
q = bSW + (bSE - bSW) * fx
b = ( p + (q - p) * fy )
b[b<0] = 0.0
b[b>1] = 1.0
img[:, :, 0] = r
img[:, :, 1] = g
img[:, :, 2] = b
plt.figure(1)
plt.imshow(img)
plt.axis('off');
plt.show();

附录：PS 色调— —颜色梯度

  clc;
  clear all;
  close all;
  addpath('E:\PhotoShop Algortihm\Image Processing\PS Algorithm');
  I=imread('4.jpg');
  Image=double(I)/255;
  [height, width, depth]=size(Image);
  rNW=1.0;   gNW=0.0;  bNW=0.0;
  rNE=1.0;   gNE=1.0;  bNE=0.0;
  rSW=0.0;   gSW=0;   bSW=1.0;
  rSE=0.0;   gSE=1.0;  bSE=0.0;
  Img_new=Image;
  for ii=1:height
    for jj=1:width
      fx = jj / width;
      fy = ii / height;
      p = rNW + (rNE - rNW) * fx;
      q = rSW + (rSE - rSW) * fx;
      r = ( p + (q - p) * fy );
      r = min(max(r, 0), 1);
      p = gNW + (gNE - gNW) * fx;
      q = gSW + (gSE - gSW) * fx;
      g = ( p + (q - p) * fy );
      g = min(max(g, 0) ,1);
      p = bNW + (bNE - bNW) * fx;
      q = bSW + (bSE - bSW) * fx;
      b = ( p + (q - p) * fy );
      b = min(max(b, 0), 1);
      Img_new(ii, jj, 1)=r;
      Img_new(ii, jj, 2)=g;
      Img_new(ii, jj, 3)=b;
    end  
  end
  imshow(Img_new);
  imwrite(Img_new, 'out.jpg');

参考来源：http://www.jhlabs.com/index.html

本例Python运行效果图：

原图：

Python实现PS图像调整颜色梯度效果示例