PS 滤镜— — 万花筒效果

    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');

参考来源：http://www.jhlabs.com/index.html

原图：

效果图：