Python实现PS图像调整颜色梯度效果示例_Python

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');