How to add active contours to bounding box in live video

Here is developed model for face detection using 'VIOLA AND JOHNES ALGORITHM' and 'CAMShift'. It is using a bounding box to track and detect face. I want to add active contours / dynamic active contours to get the exact shape of the face in the live video. It should only catch the contours of the face not its features. How do I add the active contours within the live video in matlab?

    faceDetector = vision.CascadeObjectDetector();

    %Get the input device using image acquisition toolbox,resolution = 640x480 to improve performance
    obj =imaq.VideoDevice('winvideo', 1, 'YUY2_320x240','ROI', [1 1 320 240]);
    set(obj,'ReturnedColorSpace', 'rgb');
    figure('menubar','none','tag','webcam');

    while (true)
        frame=step(obj);
        bbox=step(faceDetector,frame);

        boxInserter  = insertObjectAnnotation(frame,'rectangle',bbox, 'Face Detected');

        imshow(boxInserter,'border','tight');

        f=findobj('tag','webcam');

        if (isempty(f));
            [hueChannel,~,~] = rgb2hsv(frame);

    % Display the Hue Channel data and draw the bounding box around the face.
    figure, imshow(hueChannel), title('Hue channel data');

    rectangle('Position',bbox,'EdgeColor','r','LineWidth',1, 'Face Detected')
    hold off
    noseDetector = vision.CascadeObjectDetector('Nose');
    faceImage    = imcrop(frame,bbox);
    imshow(faceImage)  
    noseBBox     = step(noseDetector,faceImage);

    noseBBox(1:1) = noseBBox(1:1) + bbox(1:1);
    videoInfo    = info(obj);
    ROI=get(obj,'ROI');
    VideoSize = [ROI(3) ROI(4)];

    videoPlayer  = vision.VideoPlayer('Position',[300 300 VideoSize+30]);
    tracker = vision.HistogramBasedTracker;
    initializeObject(tracker, hueChannel, bbox);

    while (1)

    % Extract the next video frame
        frame = step(obj);
    % RGB -> HSV
        [hueChannel,~,~] = rgb2hsv(frame);

        % Track using the Hue channel data
        bbox = step(tracker, hueChannel);

        % Insert a bounding box around the object being tracked

        %Insert text coordinates

        % Display the annotated video frame using the video player object
        step(videoPlayer);
        pause (.2)
    end

    % Release resources
    release(obj);
    release(videoPlayer);

            close(gcf)

            break
        end
        pause(0.05)
    end
    release(obj)