matlab旋转实现(最近邻值-双线性-三次卷积插值实现插值).docx

对图像进行旋转，使用最近邻插值法，双线性插值，三次卷积插值三种方法进行插值。源码：clc;clear all;close all;Img=imread(test1.bmp); Img=double(Img);h w=size(Img);alpha=pi/6; %逆时针旋转的角度wnew=w*cos(alpha)+h*sin(alpha); %新图像的宽widthhnew=w*sin(alpha)+h*cos(alpha); %新图像的高heighth wnew=ceil(wnew); %取整hnew=ceil(hnew);u0=w*sin(alpha); %平移量T=cos(alpha),sin(alpha);-sin(alpha),cos(alpha); %变换矩阵 Imgnew1=zeros(hnew,wnew); Imgnew2=zeros(hnew,wnew);Imgnew3=zeros(hnew,wnew);for u=1:hnew %u和v是新图像坐标，变换到原图像坐标x和y中。 for v=1:wnew tem=T*(u;v-u0;0); x=tem(1); y=tem(2); if x=1 & x=1 & y=w %若变换出的x和y在原图像范围内 x_low=floor(x); x_up=ceil(x); y_low=floor(y); y_up=ceil(y); if (x-x_low)=(x_up-x) %采用最近点法，选取距离最近点的像素赋给新图像 x=x_low; else x=x_up; end if (y-y_low)=2 & x=2 & y=w-2 %若变换出的x和y在原图像范围内 x_1=floor(x)-1; x_2=floor(x); x_3=floor(x)+1; x_4=floor(x)+2; y_1=floor(y)-1; y_2=floor(y); y_3=floor(y)+1; y_4=floor(y)+2; A=sw(1+x-x_2),sw(x-x_2),sw(1-(x-x_2),sw(2-(x-x_2); C=sw(1+y-y_2),sw(y-y_2),sw(1-(y-y_2),sw(2-(y-y_2); B= Img(x_1,y_1),Img(x_1,y_2),Img(x_1,y_3),Img(x_1,y_4); Img(x_2,y_1),Img(x_2,y_2),Img(x_2,y_3),Img(x_2,y_4); Img(x_3,y_1),Img(x_3,y_2),Img(x_3,y_3),Img(x_3,y_4); Img(x_4,y_1),Img(x_4,y_2),Img(x_4,y_3),Img(x_4,y_4); Imgnew3(u,v)=A*B*C; end end endsubplot(2,2,1),imshow(Img,),title(原图);subplot(2,2,2),imshow(Imgnew1,),title(最近邻插值法);subplot(2,2,3),imshow(Img