6 research outputs found
Global Motion Estimation and Its Applications
In this chapter, global motion estimation and its applications are given. Firstly we give the definitions of global motion and global motion estimation. Secondly, the parametric representations of global motion models are provided. Thirdly, global estimation approaches including pixel domain based global motion estimation, hierarchical globa
Fast search algorithms for digital video coding
PhD ThesisMotion Estimation algorithm is one of the important issues in video coding standards
such as ISO MPEG-1/2 and ITU-T H.263. These international standards regularly use a
conventional Full Search (FS) Algorithm to estimate the motion of pixels between pairs
of image blocks. Since a FS method requires intensive computations and the distortion
function needs to be evaluated many times for each target block. the process is very
time consuming. To alleviate this acute problem, new search algorithms, Orthogonal
Logarithmic Search (OLS) and Diagonal Logarithmic Search (DLS), have been
designed and implemented.
The performance of the algorithms are evaluated by using standard 176x 144 pixels
quarter common intermediate format (QCIF) benchmark video sequences and the results
are compared to the traditional well-known FS Algorithm and a widely used fast search
algorithm called the Three Step Search (3SS), The fast search algorithms are known as
sub-optimal algorithms as they test only some of the candidate blocks from the search
area and choose a match from a subset of blocks. These algorithms can reduce the
computational complexity as they do not examine all candidate blocks and hence are
algorithmically faster. However, the quality is generally not as good as that of the FS
algorithms but can be acceptable in terms of subjective quality.
The important metrics, time and Peak Signal to Noise Ratio are used to evaluate the
novel algorithms. The results show that the strength of the algorithms lie in their speed
of operation as they are much faster than the FS and 3SS. The performance in speed is
improved by 85.37% and 22% over the FS and 3SS respectively for the OLS. For the
DLS, the speed advantages are 88.77% and 40% over the FS and 3SS. Furthermore, the
accuracy of prediction of OLS and DLS are comparahle to the 3SS.Thepsatri Rajabhat University:
Royal Thai Government
Novel block-based motion estimation and segmentation for video coding
EThOS - Electronic Theses Online ServiceGBUnited Kingdo