matlab旋轉(zhuǎn)實(shí)現(xiàn)最近鄰值雙線性三次卷積插值實(shí)現(xiàn)插值

1、對(duì)圖像進(jìn)行旋轉(zhuǎn)，使用最近鄰插值法，雙線性插值，三次卷積插值三種方法進(jìn)行插值。源碼：clc;clear all;close all;Img=imread('test1.bmp'); Img=double(Img);h w=size(Img);alpha=pi/6; %逆時(shí)針旋轉(zhuǎn)的角度wnew=w*cos(alpha)+h*sin(alpha); %新圖像的寬widthhnew=w*sin(alpha)+h*cos(alpha); %新圖像的高h(yuǎn)eighth wnew=ceil(wnew); %取整hnew=ceil(hnew);u0=w*sin(alpha); %平移量T=cos

2、(alpha),sin(alpha);-sin(alpha),cos(alpha); %變換矩陣 Imgnew1=zeros(hnew,wnew); Imgnew2=zeros(hnew,wnew);Imgnew3=zeros(hnew,wnew);for u=1:hnew %u和v是新圖像坐標(biāo)，變換到原圖像坐標(biāo)x和y中。 for v=1:wnew tem=T*(u;v-u0;0); x=tem(1); y=tem(2); if x>=1 & x<=h & y>=1 & y<=w %若變換出的x和y在原圖像范圍內(nèi) x_low=floor(x);

3、x_up=ceil(x); y_low=floor(y); y_up=ceil(y); if (x-x_low)<=(x_up-x) %采用最近點(diǎn)法，選取距離最近點(diǎn)的像素賦給新圖像 x=x_low; else x=x_up; end if (y-y_low)<=(y_up-y) y=y_low; else y=y_up; end p1=Img(x_low,y_low); %雙線性插值，p1到p4是（x,y）周圍的四個(gè)點(diǎn) p2=Img(x_up,y_low); p3=Img(x_low,y_low); p4=Img(x_up,y_up); s=x-x_low; t=y-y_low;

4、Imgnew1(u,v)=Img(x,y); Imgnew2(u,v)=(1-s)*(1-t)*p1+(1-s)*t*p3+(1-t)*s*p2+s*t*p4; end if x>=2 & x<=h-2 & y>=2 & y<=w-2 %若變換出的x和y在原圖像范圍內(nèi) 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(

5、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('原圖');subplot(2,2,2),imshow(Imgnew1,),title('最近鄰插值法');subplot(2,2,3),imshow(Imgn