how can i detect circle object in this image?

i need to detect circle objet in this image

Answer 1

[Image Analyst]

Well the simple but probably not the best way is to just threshold, then get rid of noise blobs with bwareaopen() or bwareafilt(). You will find a basic image segmentation tutorial based on thresholding in my File Exchange: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

You will find more sophisticated algorithms here: http://www.visionbib.com/bibliography/contentsmedical.html#Medical%20Applications,%20CAT,%20MRI,%20Ultrasound,%20Heart%20Models,%20Brain%20Models