怎样用matlab实现图像的缩放,用matlab对图像进行缩放与旋转

%======用matlab对图像进行缩放(双线性插值法)

clear;   %此题是用双线性插值法实现图像缩放

I=imread('f.jpg');

%读入原图像，只需将此处的文件换成要变换的图片即可

%图像属性

%  Filename: 'f.jpg'

%

FileModDate: '24-Aug-2008 16:50:30'

%           FileSize: 20372

%

Format: 'jpg'

%      FormatVersion: ''

%              Width: 480

%

Height: 640

%           BitDepth: 8

%          ColorType:

'grayscale'

%    FormatSignature: ''

%    NumberOfSamples: 1

%

CodingMethod: 'Huffman'

%      CodingProcess: 'Sequential'

%

Comment: {}

[rows,cols]=size(I);

K1 = str2double(inputdlg('请输入行缩放倍数', 'INPUT scale factor', 1,

{'0.5'}));%行默认变为原来的0.5倍

K2 = str2double(inputdlg('请输入列缩放倍数', 'INPUT

scale factor', 1, {'0.4'}));%列默认变为原来的0.4倍

width = K1 * rows;

height = K2 * cols;

Out = uint8(zeros(width,height));  %创建输出图像矩阵

widthScale = rows/width;

heightScale = cols/height;

for x = 6:width - 6           % 6是为了防止矩阵超出边界溢出

for y = 6:height - 6

oldX = x * widthScale;     % oldX,oldY为原坐标，x,y为新坐标

oldY = y * heightScale;

if (oldX/double(uint16(oldX)) == 1.0) &

(oldY/double(uint16(oldY)) == 1.0)

Out(x,y) = I(int16(oldX),int16(oldY));%若oldX，oldY为整数，直接赋值

else

a = double(uint16(oldX));

b = double(uint16(oldY));

x11 = double(I(a,b));                % x11 赋值为 I(a,b)

x12 = double(I(a,b+1));              % x12 赋值为 I(a,b+1)

x21 = double(I(a+1,b));              % x21 赋值为 I(a+1,b)

x22 = double(I(a+1,b+1));            % x22 赋值为

I(a+1,b+1)

Out(x,y) = uint8( (b+1-oldY) * ((oldX-a)*x21 +

(a+1-oldX)*x11) + (oldY-b) * ((oldX-a)*x22 +(a+1-oldX) * x12) );    %

用双线性插值计算公式计算

end

end

end

imshow(I);

figure;

imshow(Out);

%===============使用matlab对图片进行缩放(最近邻域法)

clear;  %此题是用最近邻域法实现图像缩放

I=imread('f.jpg');%读入图像

%图像属性

%

Filename: 'f.jpg'

%       FileModDate: '24-Aug-2008 16:50:30'

%

FileSize: 20372

%             Format: 'jpg'

%      FormatVersion:

''

%              Width: 480

%             Height: 640

%

BitDepth: 8

%          ColorType: 'grayscale'

%

FormatSignature: ''

%    NumberOfSamples: 1

%       CodingMethod:

'Huffman'

%      CodingProcess: 'Sequential'

%            Comment:

{}

[rows,cols]=size(I);

K1 = str2double(inputdlg('请输入行缩放倍数', 'INPUT scale factor', 1,

{'0.6'}));%行默认变为原来的0.6倍

K2 = str2double(inputdlg('请输入列缩放倍数', 'INPUT

scale factor', 1, {'0.4'}));%列默认变为原来的0.4倍

width = K1 * rows;

height = K2 * cols;

im2 = uint8(zeros(width,height)); %定义输出图像矩阵

widthScale = rows/width;

heightScale = cols/height;

for x = 6:width - 6         %为防止矩阵溢出而选择的参数6

for y = 6:height - 6

oldX = x * widthScale; %oldX，oldY为原坐标，x，y为新坐标

oldY = y * heightScale;

if (oldX/double(uint16(oldX)) == 1.0) &

(oldY/double(uint16(oldY)) == 1.0)

im2(x,y) = I(int16(oldX),int16(oldY));

else

a = double(round(oldX));

b = double(round(oldY)); %若不是整数四舍五入后把临近值赋过去

im2(x,y) = I(a,b);

end

end

end

imshow(I); %输出原图像

figure;

imshow(im2); %输出缩放后图像

%====================用matlab对图像进行旋转(双线性插值法)

clear;%此题是用最近邻域法实现图像旋转

im1=imread('b.jpg');

[m,n,p]=size(im1);

%

将图像旋转30度

a=0.5; %a=sin30=0.5

b=0.866;  %b=cos30=0.866

row=n*a+m*b;

col=n*b+m*a;

for

i=1:row                                %先把图象填充成全黑

for j=1:col

im2(i,j,:)=uint8(0);

end

end

for i=1:m                                          %把原图象像素点旋转后变为新图象点

for j=1:n

xx=round(abs((i-m/2)*b-(j-n/2)*a+row/2));

yy=round(abs((i-m/2)*a+(j-n/2)*b+col/2));

for k=1:3

im2(xx,yy,k)=im1(i,j,k);

end

end

end

temp1=uint8(0);

temp2=uint8(0);

temp3=uint8(0);

for i=1:row                                        %把画面上的空点按照最近邻插值法填充

temp1=uint8(0);

temp2=uint8(0);

temp3=uint8(0);

for j=1:col                                    %找到最右的图象边界点

if

(im2(i,j,:)==uint8(0))

else

kk=j;

end

end

for j=1:kk

if (im2(i,j,:)==uint8(0))

im2(i,j,1)=temp1;

im2(i,j,2)=temp2;

im2(i,j,3)=temp3;

else

temp1=im2(i,j,1);

temp2=im2(i,j,2);

temp3=im2(i,j,3);

end

end

end

imshow(im1);

figure;

imwrite(im1,'5.jpg');

%保存原图像

imshow(im2);

imwrite(im2,'6.jpg');%保存旋转后图像

%======================用matlab对图片进行旋转(最近邻域法)

clear;%此题是用最近邻域法实现图像旋转

im1=imread('b.jpg');

[m,n,p]=size(im1);

%

将图像旋转30度

a=0.5; %a=sin30=0.5

b=0.866;  %b=cos30=0.866

row=n*a+m*b;

col=n*b+m*a;

for

i=1:row                                %先把图象填充成全黑

for j=1:col

im2(i,j,:)=uint8(0);

end

end

for i=1:m                                          %把原图象像素点旋转后变为新图象点

for j=1:n

xx=round(abs((i-m/2)*b-(j-n/2)*a+row/2));

yy=round(abs((i-m/2)*a+(j-n/2)*b+col/2));

for k=1:3

im2(xx,yy,k)=im1(i,j,k);

end

end

end

temp1=uint8(0);

temp2=uint8(0);

temp3=uint8(0);

for i=1:row                                        %把画面上的空点按照最近邻插值法填充

temp1=uint8(0);

temp2=uint8(0);

temp3=uint8(0);

for j=1:col                                    %找到最右的图象边界点

if

(im2(i,j,:)==uint8(0))

else

kk=j;

end

end

for j=1:kk

if (im2(i,j,:)==uint8(0))

im2(i,j,1)=temp1;

im2(i,j,2)=temp2;

im2(i,j,3)=temp3;

else

temp1=im2(i,j,1);

temp2=im2(i,j,2);

temp3=im2(i,j,3);

end

end

end

imshow(im1);

figure;

imwrite(im1,'5.jpg');

%保存原图像

imshow(im2);

imwrite(im2,'6.jpg');%保存旋转后图像