Python实现PS滤镜的万花筒效果示例_Python

本文实例讲述了Python实现PS滤镜的万花筒效果。分享给大家供大家参考，具体如下：

这里用 Python 实现 PS 的一种滤镜效果，称为万花筒。也是对图像做各种扭曲变换，最后图像呈现的效果就像从万花筒中看到的一样：

图像的效果可以参考附录说明。具体Python代码如下：

									import matplotlib.pyplot as plt

									from skimage import io

									from skimage import img_as_float

									import numpy as np

									import numpy.matlib

									import math

									file_name='D:/Visual Effects/PS Algorithm/4.jpg';

									img=io.imread(file_name)

									img = img_as_float(img)

									row, col, channel = img.shape

									# set the parameters

									radius = 100.0

									angle = math.pi/3

									angle2 = math.pi/4

									sides = 10.0

									# set the center of the circle, proportion of the image size

									centerX = 0.5

									centerY = 0.5

									iWidth=col

									iHeight=row

									center_x=iWidth*centerX

									center_y=iHeight*centerY

									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)

									xx_dif = x_mask - center_x

									yy_dif = y_mask - center_y

									r = np.sqrt(xx_dif * xx_dif + yy_dif * yy_dif)

									theta = np.arctan2(yy_dif, xx_dif+0.0001) - angle - angle2

									temp_theta=theta/math.pi*sides*0.5

									temp_r = np.mod(temp_theta, 1.0)

									mask_1 = temp_r < 0.5

									theta = temp_r * 2 * mask_1 + (1-temp_r) * 2 * (1 - mask_1)

									radius_c=radius/np.cos(theta)

									temp_r = np.mod (r/radius_c, 1.0)

									mask_1 = temp_r < 0.5

									r = radius_c * (temp_r * 2 * mask_1 + (1-temp_r) * 2 * (1 - mask_1))

									theta = theta + angle

									x1_mask = r * np.cos(theta) + center_x

									y1_mask = r * np.sin(theta) + center_y

									mask = x1_mask < 0

									x1_mask = x1_mask * (1 - mask)

									mask = x1_mask > (col - 1)

									x1_mask = x1_mask * (1 - mask) + (x1_mask * 0 + col -2) * mask

									mask = y1_mask < 0

									y1_mask = y1_mask * (1 - mask)

									mask = y1_mask > (row -1)

									y1_mask = y1_mask * (1 - mask) + (y1_mask * 0 + row -2) * mask

									img_out = img * 1.0

									int_x = np.floor (x1_mask)

									int_x = int_x.astype(int)

									int_y = np.floor (y1_mask)

									int_y = int_y.astype(int)

									p_mask = x1_mask - int_x

									q_mask = y1_mask - int_y

									img_out = img * 1.0

									for ii in range(row):

									  for jj in range (col):

									    new_xx = int_x [ii, jj]

									    new_yy = int_y [ii, jj]

									#    p = p_mask[ii, jj]

									#    q = q_mask[ii, jj]

									    img_out[ii, jj, :] = img[new_yy, new_xx, :]

									plt.figure (1)

									plt.imshow (img)

									plt.axis('off')

									plt.figure (2)

									plt.imshow (img_out)

									plt.axis('off')

									plt.show()

附：PS 滤镜万花筒效果原理

									clc;

									clear all;

									close all;

									addpath('E:\PhotoShop Algortihm\Image Processing\PS Algorithm');

									I=imread('4.jpg');

									I=double(I);

									Image=I/255;

									sz=size(Image);

									% set the parameters

									radius = 150;

									angle = pi/4;

									angle2=pi/4;

									sides=10;

									centerX = 0.5;  % set the center of the circle, proportion of the image size

									centerY = 0.5;

									iWidth=sz(2);

									iHeight=sz(1);

									icenterX=iWidth*centerX;

									icenterY=iHeight*centerY;

									Image_new=Image;

									for i=1:sz(1)

									  for j=1:sz(2)

									    dx=j-icenterX;

									    dy=i-icenterY;

									    r=sqrt(dy*dy+dx*dx);

									    theta=atan2(dy, dx)-angle-angle2;

									    temp_theta=theta/pi*sides*0.5 ;

									    theta=triangle(temp_theta);

									    if (radius)

									      c=cos(theta);

									      radius_c=radius/c;

									      r=radius_c * triangle(r/radius_c);

									    end

									    theta=theta+angle;

									    x=r * cos(theta)+icenterX;

									    y=r * sin(theta)+icenterY;

									    if (x<=1)   x=1; end

									    if (x>=sz(2)) x=sz(2)-1; end;

									    if (y>=sz(1)) y=sz(1)-1; end;

									    if (y<1) y=1;   end;

									% % %     if (x<=1)   continue; end

									% % %     if (x>=sz(2))  continue; end;

									% % %     if (y>=sz(1)) continue; end;

									% % %     if (y<1) continue;   end;

									    x1=floor(x);

									    y1=floor(y);

									    p=x-x1;

									    q=y-y1;

									    Image_new(i,j,:)=(1-p)*(1-q)*Image(y1,x1,:)+p*(1-q)*Image(y1,x1+1,:)...

									      +q*(1-p)*Image(y1+1,x1,:)+p*q*Image(y1+1,x1+1,:);

									  end

									end

									imshow(Image_new)

									imwrite(Image_new, 'out.jpg');