Image Processing Reference
In-Depth Information
around. It is common for filmed content to suffer from gate weave. This happens during
shooting and also during playback. Several different aspects of the film process cause
unwanted movement. Video is less susceptible to these, and modern cameras have built-
in stabilizers to reduce the effects of handheld movement.
Figure 34-1 shows various axes of movement. There is a modern style of camera
operation much favored by trendy TV programs wherein the camera is operated in a
handheld fashion, even in situations where a locked-down and tripod-mounted camera
would have been better. So, this handheld movement relative to the frame may be pur-
poseful. Now, shaky movement may be acceptable when one is newsgathering in a war
zone or presenting a point of view from a rollercoaster. It is completely unnecessary when
one is filming a chef demonstrating how to cook a meal in a lifestyle program.
Introducing any additional movement is a bad thing to do while shooting content
that is intended to be compressed. Inadvertent handheld movement can be tracked out
and removed. Movement due to camera gate weave and movement of the substrate in the
projector or telecine gate can be eliminated by tracking the exposed edges of the frame.
Tracking the exposure edges will leave any handheld wobble in the shot if that is what you
want to achieve.
Camera gate weave
between frames
Track objects to eliminate
camera shake
Motion within frame
Track frame edge to eliminate
projector and camera gateweave
Figure 34-1 Instability within the framed area.
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