Image Segmentation - Image Analysis

I am working on segmenting B-mode ultrasound images and was hoping to get some advice on the problem below.

I am given an animation.avi file which contains 231 frames of 2D B-mode ultrasound images. The given task is to load each frame into matlab, make it a binary image, and segment the circular inclusion in the image. Ideally, I want to segment it to have a black background with a white circle corresponding to the lesion. My current attempt at doing this is given in the code below. The code itself is doing an ok job at isolating the white lesion from the background (attached image), but I was wondering if anyone had a better method to segment it from the background?

In addition, I want to take the white circular lesion from each frame and reconstruct a 3D image of the cylinder it forms. It has been suggested to me to use VolumeViewer in matlab, but was hoping to get some advice on how I could implement this too.

% Read the AVI file
% Find number of frames, video height, and video width
videoObject=VideoReader('animation.avi');
numberOfFrames = videoObject.NumberOfFrames;
vidHeight = videoObject.Height;
vidWidth = videoObject.Width;

%Iterate through each frame
for frame = 1:numberOfFrames
    currentFrame = read(videoObject, frame); % Reading current frame
    
    hImage = subplot(1,2,1); % Create a subplot
    image(currentFrame); % plot the current frame
    caption = sprintf('Greyscale - Frame %4d of %d.', frame, numberOfFrames);
    title(caption, 'FontSize', 22);
    drawnow; % Force it to refresh the window.

    BW = imgaussfilt(currentFrame, 8); % apply filter
    BW = imbinarize(BW, 0.65); % make binary image using threshold
    bwImage = subplot(1,2,2); % place next to original frame
    image(BW);
    caption = sprintf('BW - Frame %4d of %d.', frame, numberOfFrames);
    title(caption, 'FontSize', 22);
    drawnow; % Force it to refresh the window.
end

Answer 1

[Sneha Bhukya]

Hello Matija Jankovic,

In order to improve your current code i.e., to decrease the number of holes in the background, you can try using morphological operations that fill in gaps.

Here is a link that might help: Morphologically close image - MATLAB imclose (mathworks.com)

For stacking up circular lesions from each frame into a 3D cylinder, you can refer to this answer : Stacking multiple 2D images to form 3D image. - MATLAB Answers - MATLAB Central (mathworks.com)