影象的旋轉是不改變影象的灰度值的，這是將原始位置對映到新的位置。

Image = imread('pout.tif');
[X,Y]=size(Image); 

imshow(Image); 
Angle = pi/6;

%計算四個角點的新座標，確定旋轉後的顯示區域 
LeftTop(1,1)=-(Y-1)*sin(Angle); 
LeftTop(1,2)=(Y-1)*cos(Angle); 

LeftBottom(1,1)=0; 
LeftBottom(1,2)=0; 

RightTop(1,1
 
)=(X-1)*cos(Angle)-(Y-1)*sin(Angle); 
RightTop(1,2)=(X-1)*sin(Angle)+(Y-1)*cos(Angle); 

RightBottom(1,1)=(X-1)*cos(Angle); 
RightBottom(1,2)=(X-1)*sin(Angle); 

%計算顯示區域的行列數 
Xnew=max([LeftTop(1,1),LeftBottom(1,1),RightTop(1,1),RightBottom(1,1)])-min([LeftTop(1,1),LeftBottom(1,1),RightTop(1,1),RightBottom(1
 
,1)]); 
Ynew=max([LeftTop(1,2),LeftBottom(1,2),RightTop(1,2),RightBottom(1,2)])-min([LeftTop(1,2),LeftBottom(1,2),RightTop(1,2),RightBottom(1,2)]); 

% 分配新顯示區域矩陣 
ImageNew=zeros(round(Xnew),round(Ynew)); 

%計算原影象各畫素的新座標 
for indexX=0:(X-1) 
    for indexY=0:(Y-1) 
      ImageNew(round(indexX*cos(Angle)-indexY*sin
 
(Angle))+ ...
               round(abs(min([LeftTop(1,1),LeftBottom(1,1),
          RightTop(1,1),RightBottom(1,1)])))+1,1+round(indexX*sin(Angle)+indexY*cos(Angle))+round(abs(min([LeftTop(1,2),LeftBottom(1,2),RightTop(1,2),RightBottom(1,2)]))))=Image(indexX+1,indexY+1); 
  end  
end 

h=(ImageNew)/255; 
h=medfilt2(h); 
figure,imshow(h) 
imwrite(h,'rotate.jpg','quality',100);