The document discusses the importance of motion estimation in digital video compression for managing large multimedia data objects efficiently. It highlights that motion estimation exploits temporal redundancy between frames, allowing for reduced memory storage and costs in transmission. The principles of motion estimation, particularly motion compensation, utilize motion vectors for reconstructing video frames by predicting current frames from reference frames.

1. The Motion Estimation
Introduction & Principles

2. Digital Video
• Video has been a major part of public
consciousness for over 50 years.
• Digital video compression plays an important
role in the multimedia applications.
• In order to manage large multimedia data
objects efficiently, these data objects need to
be compressed to reduce the size for storage .

3. Video Compression
• Video Compression tries to eliminate the
temporal redundancy between adjacent
frames.
• Once the redundancies are removed the
object requires less memory space. So being
smaller in size, it takes less time for
transmission over the network.
• This in turn significantly reduces storage and
transmission costs.

4. INTRODUCTION
• Motion estimation has proven to be effective
in exploiting the temporal redundancy of
video sequences and therefore forms a central
part of all hybrid video compression
standards.
• Intuition suggests that moving pictures have a
pixel conservation property -that pixels on
one frame may be translated to form the pixel
patterns on a subsequent frame.

5. ...INTRODUCTION
• Images corresponding to objects on one frame
move within the frame to form corresponding
objects on the subsequent frame.
• Temporal redundancy that exists between
successive frames may be exploited in a
number of ways.
• The simplest method of exploiting temporal
redundancy is frame differencing.
• This strategy assumes that the average
motion is small and simply compresses the
pixel differences between two frames.

6. Principles of Motion Estimation
• Motion estimation and motion compensated
prediction is by far the most efficient and
widely used technique for achieving the high
levels of compression that are typified in
modern video compression standards.
• In this techniques, a scene or frame is divided
arbitrarily into macroblock (MB) regions. The
assumption is that each MB is composed of
closely associated pixels.

7. Motion Compensation
• During reconstruction, the reference frame is
used to predict the current frame using the
motion vectors. This technique is known as
motion compensation.
• During motion compensation, the macroblock
in the reference frame that is referenced to by
the motion vector is copied into the
reconstructed frame.

8. Learn More
in
IIT Kharagpur's
First Online
Certificate Course on
Image and
Video Communication
[Refer: http://goo.gl/hMyYWa ;
courses@wiziq.com]