how can thresold the gray scale image manually using canny method for thresholding and get the only object in image

please tell me how to do thresholding and get only one object projectdir = 'E:\SHIVA BACKUP\THYROID\P1\newcodes\data1\13002'; %y = 72; X = zeros(128, 128, 1, 72,'uint16'); % Read the series of images. % for p=1 p=1; thisfile = sprintf('IM_%d.dcm', p); filename = fullfile( projectdir, thisfile ); imdata = dicomread(filename); imsize = size(imdata); if ~isequal( imsize, [128 128 1 72] ) fprintf('file is unexpected size %s instead of [128 128 1 72], skipping "%s"\n', mat2str(imsize), filename); else X(:, :, :, :,p) = imdata; end figure(); montage(X(:,:,:,:,p), [0 100])

v=zeros(128,128,72);
s=zeros(128,128,72);
sum=0;
THRESH=20;

for i=1:18 v(:,:,i)=X(:,:,:,i); s(:,:,i)=edge(v(:,:,i),'canny',THRESH);%'both',10); figure() imshow(s(:,:,i),[]) end

Answer 1

[Image Analyst]

We can't read your code because you have not read this link yet.

See my interactive/visual thresholding application here: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

[andhavarapu lokesh]

thanks a lot your code worked but iam having a problem actually i wanted to return the thresholded binary image and crop that can you please tell me what should i add to return the binary image to your code

[Image Analyst]

That's a good suggestion for me to add this line to the OutputFcn. But until then, just after you call the function, use this code to get the binary image:

binaryImage = (lowThreshold <= grayImage) & (grayImage<= highThreshold);

[andhavarapu lokesh]

where i should keep this line in your code please tell me

Answer 2

[Belie]

hello image analyst,finding the actual thresold is so challenging..how I find it

[Image Analyst]

Just move the sliders in my app until you get something that looks best.