In the Image Processing panel, crop the actor
face from the image so as to remove a needless background
and enlarge the facial image you wish to work with.
Click the Zoom In
button (Shortcut: + or Shift + "=") to zoom in the face
area.
Click the Crop Tool
button and drag a marquee around the head to create a crop
box, as the actor animation is based on the head only.
If the actor head is slightly tilted, use the corner handles
of the marquee to
rotate the crop box until the arrow handle is parallel to
the nose.