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。
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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();
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附录:PS 色调— —颜色梯度
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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' );
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参考来源:http://www.jhlabs.com/index.html
本例Python运行效果图:
原图:
运行效果:
希望本文所述对大家Python程序设计有所帮助。
原文链接:http://blog.csdn.net/matrix_space/article/details/72302964