transform.m

这是<<Matlab在图像处理中的应用>>这本书的源码

function [J]=transform(I)
[m,n]=size(I);
Ar = size(I,1);     % Ar = number of rows of the input image
Ac = size(I,2);     % Ac = number of columns of the input image
Center = [(Ac+1)/2 (Ar+1)/2];
rm=35;
J=zeros(2*rm+1,2*rm+1);
for i=1:m
    for j=1:n
        the=pi*j/n;%y
        ri=rm/4+3*i*rm/(4*m);
        xx=ri*cos(the)+rm;
        xx=round(xx);
        yy=rm-ri*sin(the);
        yy=round(yy);
       
        the1=pi*j/n+pi;%y
        ri1=rm/4+3*i*rm/(4*m);
        xx1=ri1*cos(the1)+rm;     
        xx1=round(xx1);
        
        yy1=rm-ri*sin(the1);
        yy1=round(yy1); 
      if(xx>0&xx<=2*rm&yy>0&yy<=2*rm)
      J(yy,xx)=I(i,j);
      end
      if(xx1>0&xx1<=2*rm&yy1>0&yy1<=2*rm)
      J(yy1,xx1)=I(i,j);
      end
          end
end
figure,imshow(J);