PS 滤镜——（扭曲）球面化 Spherize

%%%% Spherize

clc;
clear all;
close all;

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

I=imread('4.jpg');
Image=double(I);

[row, col,layer]=size(Image);
R=floor(min(row, col)/2);
a=row/2;
b=col/2;
e=a/b;
K=pi/2;

alpha=1.0;     % 控制变形程度

Image_new=Image;
for i=1:row
    for j=1:col
        y0=(row+1)/2-i;
        x0=j-(col+1)/2;
        Dis=x0.^2+y0.^2;
        if(Dis<R*R)
        % if(x0*x0/(a*a)+(y0*y0)/(b*b)<1)
            if(x0~=0)
                beta=atan(y0/x0);
                if(x0<0)
                    beta=beta+pi;
                end
            else
                beta=pi/2;
            end
            radius=asin(sqrt(Dis)/R)*R/K;
            radius=(sqrt(Dis)-radius)*(1-alpha)+radius;
            x=radius*cos(beta);
            y=radius*sin(beta);
            x=col/2+x;
            y=row/2-y;
            if(x>1 && x<col && y>1 && y<row)
                x1=floor(x);
                y1=floor(y);
                p=x-x1;
                q=y-y1;
                for k=1:layer
                Image_new(i,j,k)=(1-p)*(1-q)*Image(y1,x1,k)+p*(1-q)*Image(y1,x1+1,k)...
                             +q*(1-p)*Image(y1+1,x1,k)+p*q*Image(y1+1,x1+1,k);
                end
            end        
        end
    end
end

imshow(Image_new/255);

原图

效果图