function?[Lambda1Lambda2IxIy]=eig2image（DxxDxyDyy）
%?This?function?eig2image?calculates?the?eigen?values?from?the
%?hessian?matrix?sorted?by?abs?value.?And?gives?the?direction
%?of?the?ridge?（eigenvector?smallest?eigenvalue）?.
%?
%?[Lambda1Lambda2IxIy]=eig2image（DxxDxyDyy）
%

%
%?|?Dxx??Dxy?|
%?|??????????|
%?|?Dxy??Dyy?|


%?Compute?the?eigenvectors?of?J?v1?and?v2
tmp?=?sqrt（（Dxx?-?Dyy）.^2?+?4*Dxy.^2）;
v2x?=?2*Dxy;?v2y?=?Dyy?-?Dxx?+?tmp;

%?Normalize
mag?=?sqrt（v2x.^2?+?v2y.^2）;?i?=?（mag?~=?0）;
v2x（i）?=?v2x（i）./mag（i）;
v2y（i）?=?v2y（i）./mag（i）;

%?The?eigenvectors?are?orthogonal
v1x?=?-v2y;?
v1y?=?v2x;

%?Compute?the?eigenvalues
mu1?=?0.5*（Dxx?+?Dyy?+?tmp）;
mu2?=?0.5*（Dxx?+?Dyy?-?tmp）;

%?Sort?eigen?values?by?absolute?value?abs（Lambda1）check=abs（mu1）>abs（mu2）;

Lambda1=mu1;?Lambda1（check）=mu2（check）;
Lambda2=mu2;?Lambda2（check）=mu1（check）;

Ix=v1x;?Ix（check）=v2x（check）;
Iy=v1y;?Iy（check）=v2y（check）;

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????文件?????3938164??2009-06-11?14:40??ExampleVolumeStent.mat
?????文件????????3976??2009-12-02?22:02??FrangiFilter2D.m
?????文件????????5657??2010-03-02?16:05??FrangiFilter3D.m
?????文件????????1025??2009-06-11?15:19??Hessian2D.m
?????文件????????1938??2009-06-11?15:23??Hessian3D.m
?????文件?????????986??2009-10-27?14:46??eig2image.m
?????文件???????12432??2009-08-26?14:14??eig3volume.c
?????文件???????????0??2009-10-02?13:37??eig3volume.m
?????文件???????22500??2009-09-30?19:33??imgaussian.c
?????文件????????2073??2009-09-24?18:09??imgaussian.m
?????文件????????1335??2010-03-02?10:09??license.txt
?????文件??????116255??2009-06-11?14:03??vessel.png