Track a Face in Scene

Create System objects for reading and displaying video and for drawing a bounding box of the object.

videoReader = VideoReader('visionface.avi');
videoPlayer = vision.VideoPlayer('Position',[100,100,680,520]);

Read the first video frame, which contains the object, define the region.

objectFrame = readFrame(videoReader);
objectRegion = [264,122,93,93];

As an alternative, you can use the following commands to select the object region using a mouse. The object must occupy the majority of the region:

figure; imshow(objectFrame);

objectRegion=round(getPosition(imrect))

Show initial frame with a red bounding box.

objectImage = insertShape(objectFrame,'rectangle',objectRegion,'ShapeColor','red');
figure;
imshow(objectImage);
title('Red box shows object region');

Detect interest points in the object region.

points = detectMinEigenFeatures(im2gray(objectFrame),'ROI',objectRegion);

Display the detected points.

pointImage = insertMarker(objectFrame,points.Location,'+','MarkerColor','white');
figure;
imshow(pointImage);
title('Detected interest points');

Create a tracker object.

tracker = vision.PointTracker('MaxBidirectionalError',1);

Initialize the tracker.

initialize(tracker,points.Location,objectFrame);

Read, track, display points, and results in each video frame.

while hasFrame(videoReader)
      frame = readFrame(videoReader);
      [points,validity] = tracker(frame);
      out = insertMarker(frame,points(validity, :),'+');
      videoPlayer(out);
end

Release the video player.

release(videoPlayer);