How to extract the region of interest?

Considering an image, imrect function displays the ROI. Now I want to extract the ROI and to be stored in another variable and displayed.

    figure, imshow(inputImage);
    I = imrect(gca,[50 50 100 100]);

[Amruta Talreja]

Thanx.

[Md. Mostafizur Rahman]

Thanks. Its help me very much. But I want to do leveling using ROI, Can you tell me how I do this? My code show images and using the help of your code also show ROI but I can't save as a positive or negative leveling.

[Image Analyst]

What is "leveling"? Start a new question and post your image.

[Suniti Singh]

Hello sir I am working on medical image security. can you please help me with the code of svm classsification to classify the image into roi and nroi.

Thanks & Regards

Answer 1

[Image Analyst]

Use imcrop().

grayImage = imread('pout.tif');
imshow(grayImage);
h = imrect;
position = wait(h);

croppedImage = imcrop(grayImage, position);
figure;
imshow(croppedImage);

[Explorer]

wait() is not defined function in MATLAB.

Why have you used it?

[Image Analyst]

It is a built - in function. The code is straight out of the MATLAB help documentation for imrect . If you have wait, it will wait for you to double-click to accept the rectangle. If you don't have it, it finishes as soon as you lift the mouse button. You can do it without waiting and without using the wait function like this:

h = imrect;
% Wait for user. 
% Comment out if you don't want to wait for confirmation.
% position = wait(h); 
position = getPosition(h)

[Explorer]

Okay

Answer 2

[Amruta Talreja]

Hello Image Analyst. I got a ROI from the below code and now I want to label it. Please help me with the code of labeling a ROI. Thank you in advance. S = [1 1 50 50]; %the size of your ROI starts at point X1, Y1 I = imread('T1.tif'); % your input image figure, imshow(I); h = imrect(gca, S);

addNewPositionCallback(h,@(p) title(mat2str(p,3))); fcn = makeConstrainToRectFcn('imrect',get(gca,'XLim'),get(gca,'YLim')); setPositionConstraintFcn(h,fcn)

position = wait(h); I2 = imcrop(I,position); imshow(I2); % the output image of your ROI

[Image Analyst]

What does labeling mean to you?

In the meantime, look at these functions bwlabel(), bwconncomp(), text(), annotation().

[prahlad h]

This is not directly related to my question, but Image Analyst, could you please answer this? segmentation question

Answer 3

[Thilakam kuttiannan]

sir Can you please send me the coding for ROI for a given image

[Image Analyst]

Possibly, but only after you read this link first.

[Matpar]

Hi Image Analyst,

I am trying to understand the labelling process, please guide me..

I have 40 images for which I have labelled the region of interest ROI via the Matlab app! This was taken from the stopsign example in mathworks.

I am having some challgenges understanding how to code in the images that does not contain the region of Interest! Where does that bit fit in?

Please help me to undertand this, I am stuck and cannot move forward until I gather this understanding..

Thus far I researched the labelling process but no where I am seeing where they are implementing the processes for the non ROI images. or is this being called some where other and I am not seeing this

[Image Analyst]

It would be mostly the same code, but after segmentation you'd just check for no blobs:

[labeledImage, numberOfRegions] = bwlabel(binaryImage);
if numberOfRegions == 0
    % No blobs found.  Just exit
    return;
end
% Blobs found, so continue
props = regionprops(labeledImage, 'Area')