Detect Face and track using feature points

videoFileReader = vision.VideoFileReader('visionface.avi');
videoPlayer = vision.VideoPlayer('Position', [100, 100, 680, 520]);
objectFrame = step(videoFileReader);
objectRegion = [264, 122, 93, 93];
objectImage = insertShape(objectFrame, 'Rectangle', objectRegion,'Color', 'red');
figure; imshow(objectImage); title('Yellow box shows object region');
 points = detectMinEigenFeatures(rgb2gray(objectFrame), 'ROI', objectRegion);
 pointImage = insertMarker(objectFrame, points.Location, '+', 'Color', 'white');
figure, imshow(pointImage), title('Detected interest points');
 pointImage = insertMarker(objectFrame, points.Location, '+', 'Color', 'white');
figure, imshow(pointImage), title('Detected interest points');
tracker = vision.PointTracker('MaxBidirectionalError', 1);
 initialize(tracker, points.Location, objectFrame);
 while ~isDone(videoFileReader)
      frame = step(videoFileReader);
      [points, validity] = step(tracker, frame);
      out = insertMarker(frame, points(validity, :), '+');
      step(videoPlayer, out);
end
release(videoPlayer);
release(videoFileReader);