clear all

I=imread( lena.bmp )

figure imshow(I)

I2=imrotate(I,-4, bilinear ) 逆时针旋转4度

figure imshow(I2)

I3=fliplr(I) 垂直镜像

figure imshow(I3)

I4=imresize(I,0.5, bilinear ) 缩小为原图的1/2

figure imshow(I4)





A=double(I) 转换为double类型

计算7个不变矩

[nc,nr]=size(A)

[x,y]=meshgrid(1:nr,1:nc) 得到网格

x=x(:)

y=y(:)

A=A(:)

m.m00=sum(A)

if m.m00==0

m.m00=eps

end

m.m10=sum(x.*A)

m.m01=sum(y.*A)

计算均值

xmean=m.m10/m.m00

ymean=m.m01/m.m00

计算中心矩-li9_23.rar

cm.cm00=m.m00

cm.cm02=(sum((y-ymean).^2.*A))/(m.m00^2)

cm.cm03=(sum((y-ymean).^3.*A))/(m.m00^2.5)

cm.cm11=(sum((x-xmean).*(y-ymean).*A))/(m.m00^2)

cm.cm12=(sum((x-xmean).*(y-ymean).^2.*A))/(m.m00^2.5)

cm.cm20=(sum((x-xmean).^2.*A))/(m.m00^2)

cm.cm21=(sum((x-xmean).^2.*(y-ymean).*A))/(m.m00^2.5)

cm.cm30=(sum((x-xmean).^3.*A))/(m.m00^2.5)

im(1)=cm.cm20+cm.cm02

im(2)=(cm.cm20-cm.cm02)^2+4*cm.cm11^2

im(3)=(cm.cm30-3*cm.cm12)^2+(3*cm.cm21-cm.cm03)^2

im(4)=(cm.cm30+cm.cm12)^2+(cm.cm21+cm.cm03)^2

im(5)=(cm.cm30-3*cm.cm12)*(cm.cm30+cm.cm12)...

　 *((cm.cm30+cm.cm12)^2-3*(cm.cm21+cm.cm03)^2)...

　 +(3*cm.cm21-cm.cm03)*(cm.cm21+cm.cm03)...

　 +(3*(cm.cm30+cm.cm12)^2-(cm.cm21+cm.cm03)^2)

im(6)=(cm.cm20-cm.cm02)*((cm.cm30+cm.cm12)^2-(cm.cm21+cm.cm03)^2)...

　 +4*cm.cm11*(cm.cm30+cm.cm12)*(cm.cm21+cm.cm03)

im(7)=(3*cm.cm21-cm.cm03)*(cm.cm30+cm.cm12)...

　 *((cm.cm30+cm.cm12)^2-3*(cm.cm21+cm.cm03)^2)...

　 +(3*cm.cm12-cm.cm30)*(cm.cm21+cm.cm03)...

　 *(