motion estimation and compensation for very low bitrate video coding

10 Introduction
Once the proposed scheme is outlined, Chapter Five presents solutions
to the two main steps of the scheme: the automatic design of a mesh
adapted to the spatial contents of the reference image, and the adaptation
of the BMA vector eld so as to be applicable to the mesh. The
rst problem is addressed by detecting object contours in the image
and tracking these contours so as to extract \corners" (i.e. maximum
curvature points). The selected corners then serve asvertices of a triangular
mesh generated by Delaunay triangulation. The second problem is
solved byaninterpolation technique known as \inverse kriging". Finally,
the chapter concludes by presenting some subjective results.
Finally, a general conclusion is drawn from the obtained results. It
reviews the various contributions of the present work but also raises the
question as to which parts of the motion exploitation chain (estimation
- transmission - compensation) is it useful to take the spatial contents
of the images into account.
Contributions of the Thesis
The key contributions of the present research are summarized on the gure
below. Some of these contributions are personal, others are the result
of a close collaboration with other members of the TELE laboratory 2 .
Some are also the subject of previous publications [111, 77, 11, 73, 68,
70, 23, 69, 19, 20, 71, 75, 74, 76].
Framework
Thesis
contributions
CODER
Estimation:
motion analysis
Chap. 3
Adaptive Block-
Matching
Algorithm
Channel
Transmission
Chap. 4
Study of the
impact of preprocessing
DECODER
Motion
compensation
Chap. 5
Mesh-based
reconstruction
of BMA fields
Improve BMA with content-adapted techniques
2 Most of the work related to the COMIS scheme has been achieved in collaboration
with many other researchers in image processing at the laboratory: M.P. Queluz, B.
Simon, O. Bruyndonckx, V. Warscotte, T. Delmot, C. Devleeschouwer.