Heechan Park

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A technique for performing progressive mesh-based motion estimation in a layered fashion is presented. Motion compensation based on image warping provides a block prediction free of block artifacts. The smooth prediction can be used to identify motion-active regions by comparing with the reference frame and generate a partial denser mesh, thus forming(More)
We approach image compression using an affine symmetric image representation that exploits rotation and scaling as well as the translational redundancy present between image blocks. It resembles fractal theory in the sense that a single prototypical block is needed to represent other similar blocks. Finding the optimal prototypes is not a trivial task(More)
Multiple intra-mode prediction is one of the new features introduced in the emerging video standard, H.264/AVC. Its function is to further reduce spatial redundancies in an intracoded macroblock prior to conventional transform coding and entropy coding. However, the process is computationally expensive especially when Lagrangian cost evaluation is employed.(More)
Scalable video coding utilizing the wavelet transform applied to both the spatial and temporal domains (3D-DWT) is of current interest in video coding. In the case of the 2D+t scheme, motion estimation is required to be conducted in the wavelet domain. We explore approaches that overcome the well-known shift-variant property of the wavelet transform so that(More)
Directional information is an important component of both natural and synthetic images, and it is exploited in many image processing applications. Directional basis analysis is used to capture significant structural information. This paper presents an empirical study of image denoising with directional bases. We consider two distinct approaches. One(More)
Many natural textures comprise structural patterns and show strong self-similarity. We use affine symmetry to segment an image into self-similar regions; that is a patch of texture (blocks from a uniformly partitioned image) can be transformed to other similar patches by warping. If the texture image contains multiple regions, we then cluster patches into a(More)
A general purpose block-to-block affine transformation estimator is described. The estimator is based on Fourier slice analysis and Fourier spectral alignment. It shows encouraging performance in terms of both speed and accuracy compared to existing methods. The key elements of its success are attributed to the ability to: 1) locate an arbitrary number of(More)
A fast algorithm for mesh-based motion estimation employing uniform triangular patches is proposed. The technique utilises an embedded block model to estimate the motion of the mesh grid points. Without the need for time-consuming evaluation, the algorithm reduces the number of search iterations according to the inherent motion. A block-wise coding approach(More)