%?-----------------------------------------------------------------------
%?
%?This?function?uses?the?SUSAN?algorithm?to?find?edges?within?an?image
%?
%
%?>>image_out?=?susan（image_inthreshold）
%
%
%?Input?parameters?...?The?gray?scale?image?and?the?threshold?
%?image_out?..?（class:?double）?image?indicating?found?edges
%?typical?threshold?values?may?be?from?10?to?30
%
%
%The?following?steps?are?performed?at?each?image?pixel:?
%?（?from?the?SUSAN?webpage?http://www.fmrib.ox.ac.uk/~steve/susan/susan/node4.html?）
%?
%?Place?a?circular?mask?around?the?pixel?in?question.?
%?Calculate?the?number?of?pixels?within?the?circular?mask?which?have?similar?brightness?to?
%?the?nucleus.?These?define?the?USAN.?
%?Subtract?USAN?size?from?geometric?threshold?to?produce?edge?strength?image.?
%
%?Estimating?moments?to?find?the?edge?direction?has?not?been?implemented?.?
%?Non-maximal?suppresion?to?remove?weak?edges?has?not?been?implemented?yet.
%
%?example:
%
%?>>?image_in=imread（‘test_pattern.tif‘）;
%?>>?image?=?susan（image_in27）;
%?>>?imshow（image[]）?
%
%
%?Abhishek?Ivaturi
%?
%?-------------------------------------------------------------------------
?

?function?image_out?=?susan（imthreshold）

close?all

clc

%?check?to?see?if?the?image?is?a?color?image...
d?=?length（size（im））;
if?d==3
????image=double（rgb2gray（im））;
elseif?d==2
????image=double（im）;
end

%?mask?for?selecting?the?pixels?within?the?circular?region?（37?pixels?as
%?used?in?the?SUSAN?algorithm

mask?=?（[?0?0?1?1?1?0?0?;0?1?1?1?1?1?0;1?1?1?1?1?1?1;1?1?1?1?1?1?1;1?1?1?1?1?1?1;0?1?1?1?1?1?0;0?0?1?1?1?0?0]）;??




%?the?output?image?indicating?found?edges
R=zeros（size（image））;



%?define?the?USAN?area
nmax?=?3*37/4;

%?padding?the?image
[a?b]=size（image）;
new=zeros（a+7b+7）;
[c?d]=size（new）;
new（4:c-44:d-4）=image;
??
for?i=4:c-4
????
????for?j=4:d-4
????????
????????current_image?=?new（i-3:i+3j-3:j+3）;
????????current_masked_image?=?mask.*current_image;
???

%???Uncomment?here?to?implement?binary?thresholding

%?????????current_masked_image（find（abs（current_masked_image-current_masked_image（44））>threshold））=0;?????????
%?????????current_masked_image（find（abs（current_masked_image-current_masked_image（44））<=threshold））=1;


%???This?thresholding?is?more?stable
?????????????????
????????????
???????
????????current_thresholded?=?susan_threshold（current_masked_imagethreshold）;
????????g=sum（current_thresholded（:））;
????????
????????if?nmax????????????R（ij）?=?g-nmax;
????????else
????????????R（ij）?=?0;
????????end
????end
end

image_out=R（4:c-44:d-4）;

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件?????172231??2012-08-27?10:31??SUSAN邊緣檢測的實現代碼\1.jpg

?????文件???????2654??2012-08-27?16:27??SUSAN邊緣檢測的實現代碼\susan.m

?????文件????????655??2005-04-20?20:09??SUSAN邊緣檢測的實現代碼\susan_threshold.m

?????文件?????250454??2005-04-20?16:47??SUSAN邊緣檢測的實現代碼\test_pattern.tif

?????目錄??????????0??2012-10-15?10:18??SUSAN邊緣檢測的實現代碼

-----------?---------??----------?-----??----

???????????????426212????????????????????6