Y. Wang, O. Lee, and A. Vetro, "Use of two-dimensional deformable mesh structures for video coding, part II - the analysis problem and a region-based coder employing an active mesh representation," IEEE Transactions on Circuits and Systems for Video Technology, vol. 6, pp. 647--659, Dec. 1996.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....we aim at minimizing the square error between the original image at time t Gamma 1 and the compensated one. Alternately, backward tracking aims at minimizing this error, but at time t. A lot of mesh based motion estimation methods have been reported in literature: various block matching methods ([3]) differential methods in forward tracking ( 2] and backward tracking ( 3] Backward tracking provides good results when simply applied to two successive images, but it is damaged by the initial mesh which can not generally be considered as known on the last frame. Likewise, forward tracking ....

.... Gamma 1 and the compensated one. Alternately, backward tracking aims at minimizing this error, but at time t. A lot of mesh based motion estimation methods have been reported in literature: various block matching methods ( 3] differential methods in forward tracking ( 2] and backward tracking ([3]) Backward tracking provides good results when simply applied to two successive images, but it is damaged by the initial mesh which can not generally be considered as known on the last frame. Likewise, forward tracking suffers from an analysis synthesis problem but it allows long time trackings. ....

Y. Wang and O. Lee. Use of two-dimensional deformable mesh structures for video coding, part I-The synthesis problem: mesh-based function approximation and mapping. IEEE Trans. on Circ. and Syst. for Video Tech., 6(6):636, Dec. 96.

....then the parameters of this representation are estimated from the data. In a mesh model, the image domain is subdivided into a collection of mesh elements, the vertices of which are called nodes. The image function is then obtained over each element by interpolation from the values of these nodes [6]. In a content adaptive mesh model (CAMM) the mesh elements are placed in a fashion that is adapted to the local content of the image. A CAMM provides an efficient representation of the image in that the number of parameters (i.e. mesh nodes) is typically much less than the number of required ....

Y. Wang and L. O., "Use of two-dimensional deformable mesh structures for video coding .I. The synthesis problem: mesh-based function approximation and mapping," IEEE Trans. Circuits Syst. for Video Tech., vol. 6, pp. 636-646, 1996.

....sur la seconde. Notre problematique specifique nous fera choisir la deformation arriere, pour des raisons expliquees plus loin a la section 3. Variantes La notion de di#erence entre images fait generalement intervenir (dans le domaine du codage) une somme des carres des DFD : # p (DFD(p) 2 [WLV96] D autres formes sont bien sur possible, comme la somme des valeurs absolues # p DFD(p) NH94] ou plus generalement # p #(DFD(p) ou # est une fonction symetrique positive s annulant en zero. Cette derniere formulation met en evidence la possibilite de faire intervenir des math ....

....2.3.2 Gestion des occlusions Une facon de reduire la gravite des phenomenes dus aux discontinuites de mouvement est de considerer uniquement des maillages de zones qui ont un mouvement coherent. Cela se traduit generalement par un maillage separe pour chaque objet de la scene, comme propose dans [WLV96] Cette methode ne fonctionne que dans le cas ou l objet suivi a un mouvement regulier, ce qui peut ne pas etre le cas. Dans la pratique cependant, les discontinuites les plus importantes se situent aux limites entre les objets. Une autre solution est de gerer l apparition et la disparition de ....

[Article contains additional citation context not shown here]

Y. Wang, O. Lee, and A. Vetro. Use of two-dimensional deformable mesh structures for video coding. ii. the analysis problem and a region-based coder employing an active mesh representation. IEEE Transactions on circuits and systems for video technology, 6(6):647--659, Dec 1996. 30

....cette approche peut etre etendue a des voisinages non hexagonaux [AT97a] A cote de ces solutions specifiques aux maillages, il est aussi possible d utiliser des algorithmes numeriques generaux. En e#et, les modeles classiques peuvent se formaliser dans le cadre de la methode des elements finis[WL96] ce qui permet de proposer des methodes e#caces de mise en oeuvre [Lec99] tels que les algorithmes de descente de gradient. Une autre utilisation de cette formalisation est consideree dans [IS98] pour laquelle seules les fonctions correspondant aux deformations les plus representatives sont ....

Y. Wang and O. Lee. Use of two-dimensional deformable mesh structures for video coding. i. the synthesis problem : mesh-based function approximation and mapping. IEEE Transactions on circuits and systems for video technology, 6(6):636--646, Dec 1996.

....mesh is far more appealing due to its computational efficiency and flexibility in handling complex geometry. Mesh can be constructed either in the image plane or in the scene coordinates. The primary usage of the image mesh is assisting in the apparent motion estimation and video compensation [11]. The scene mesh is commonly used to build a numerical physical model, and usually covers only the isolated object of interest. Either the feature first scheme or the mesh first scheme can be used to generate a mesh that is adaptive to the image content, which may or may not have artificial ....

Y. Wang and O. Lee, "Use of Two-dimensional Deformable Mesh Structures for Video Coding, Part I - The Synthesis Problem: Mesh-Based Function Approximation and Mapping", IEEE Transactions on Circuits and Systems for Video Technology., 6(6), pp. 636-646, 1996.

....order transform (see equation 2.34) A Gauss Newton iterative minimization method is used in the matching process, requiring second order derivatives to be estimated. This scheme, although interesting, incurs both extra computational complexity and extra coding overhead. Wang and Lee et al. [97, 99] propose an approach using a finite element mesh (FEM) method. A key mathematical tool used in these papers (and FEM techniques in general) is that of coordinate mapping between an arbitrary element and a master element which has well designed (easily solvable) shape functions. Thus operations on ....

....[97] initially generates a regular mesh structure and then moves nodes to image features if possible. The main disadvantage in this approach is that many nodes are placed in areas of the image containing no features or texture. This problem is addressed in the second algorithm described by Wang [99], in which a quad tree approach is used which significantly reduces the number of nodes in flat regions within the image (this results in a structure of the form shown in figure 2.6(f) The node tracking is achieved by minimizing an energy function of the following form: E = w p E p w f E f ....

[Article contains additional citation context not shown here]

O. Lee Y. Wang and A. Vetro. Use of two-dimensional deformable mesh structures for video coding, Part II-The analysis problem and a region-based coder employing an active mesh representation. IEEE Transactions on Circuits and Systems for Video Technology, 6(6):647--659, December 1996.

....order transform (see equation 2.34) A Gauss Newton iterative minimization method is used in the matching process, requiring second order derivatives to be estimated. This scheme, although interesting, incurs both extra computational complexity and extra coding overhead. Wang and Lee et al. [97, 99] propose an approach using a finite element mesh (FEM) method. A key mathematical tool used in these papers (and FEM techniques in general) is that of coordinate mapping between an arbitrary element and a master element which has well designed (easily solvable) shape functions. Thus operations on ....

....elements are mapped to a regular master element which then simplifies the subsequent numerical calculations. The coding scheme outlined generates a scene adaptive approach such that nodes are locked on to features within the image (thus facilitating more accurate tracking) The first algorithm [97] initially generates a regular mesh structure and then moves nodes to image features if possible. The main disadvantage in this approach is that many nodes are placed in areas of the image containing no features or texture. This problem is addressed in the second algorithm described by Wang [99] ....

Y. Wang and O. Lee. Use of two-dimensional deformable mesh structures for video coding, Part I-The synthesis problem: Mesh-based function approximation and mapping. IEEE Transactions on Circuits and Systems for Video Technology, 6(6):636--646, December 1996.

....Others [4, 5, 6] also developed similar results. Huang and Hsu [7] introduced a hierarchical version of the motion mesh, with smaller meshes to more active regions of the image. Wang and Lee [8] used a finite element approach to the mesh problem, and explored its application in video coding [9, 10]. Tekalp et al. 11, 12] used the mesh model for manipulation of synthetic objects as well as representations in joint naturalsynthetic environments. Mesh based methods have also been used with great success in processing medical image sequences [13, 14, 15] In the mesh based model, the present ....

Y. Wang, O. Lee, and A. Vetro, "Use of two-dimensional deformable mesh structures for video coding, part II-- the analysis problem and a region-based coder employing an active mesh representation," IEEE Transactions on Circuits and Systems for Video Technology, vol. 6, pp. 647--659, December 1996.

....Others [4, 5, 6] also developed similar results. Huang and Hsu [7] introduced a hierarchical version of the motion mesh, with smaller meshes to more active regions of the image. Wang and Lee [8] used a finite element approach to the mesh problem, and explored its application in video coding [9, 10]. Tekalp et al. 11, 12] used the mesh model for manipulation of synthetic objects as well as representations in joint naturalsynthetic environments. Mesh based methods have also been used with great success in processing medical image sequences [13, 14, 15] In the mesh based model, the present ....

Y. Wang and O. Lee, "Use of two-dimensional deformable mesh structures for video coding, part I-- the synthesis problem: mesh based function approximation and mapping," IEEE Transactions on Circuits and Systems for Video Technology, vol. 6, pp. 636--646, December 1996.

.... triangular elements) and motion (each node is attributed a sequence of motion vectors describing its temporal trajectory) information [4] Other applications of 2D dynamic meshes include video object compression, tracking, and filtering, e.g. warping motion compensation [5] 6] 7] 8] 9] [10], and video indexing and retrieval, e.g. motionbased queries [11] 3D meshes are an elementary building block of the Virtual Reality September 14, 1998 DRAFT IEEE TRANSACTIONS ON CSVT, VOL. XX, NO. Y, MONTH 1998 2 Modeling Language (VRML) a standard for storing and interacting with graphics ....

....associated with the 2D dynamic mesh representation is determined by estimating forward motion vectors for mesh node point sequentially from one frame to the next, which is generally referred to as forward tracking. Various techniques have been proposed for to achieve this [22] 5] 8] 23] [10]. Although multi resolution and hierarchical motion estimation methods have been discussed widely in literature to improve efficiency and accuracy of motion estimation, hierarchical mesh based motion estimation has been addressed only for the case of uniform meshes [7] 2] Here, we extend the ....

[Article contains additional citation context not shown here]

Y. Wang, O. Lee, and A. Vetro, "Use of two-dimensional deformable mesh structures for video coding, Part II - The analysis problem and a region-based coder employing an active mesh representation," IEEE Trans. on Circuits and Systems for Video Technology, vol. 6, no. 6, pp. 647--659, Dec. 1996.

.... set of triangular elements) and motion (each node is attributed a sequence of motion vectors describing its temporal trajectory) information [4] Other applications of 2D dynamic meshes include video object compression, tracking, and filtering, e.g. warping motion compensation [5] 6] 7] 8] [9], 10] and video indexing and retrieval, e.g. motionbased queries [11] 3D meshes are an elementary building block of the Virtual Reality September 14, 1998 DRAFT IEEE TRANSACTIONS ON CSVT, VOL. XX, NO. Y, MONTH 1998 2 Modeling Language (VRML) a standard for storing and interacting with ....

Y. Wang and O. Lee, "Use of two-dimensional deformable mesh structures for video coding, Part I - The synthesis problem: Mesh-based function approximation and mapping," IEEE Trans. on Circuits and Systems for Video Technology, vol. 6, no. 6, pp. 636--646, Dec. 1996.

No context found.

Y. Wang, O. Lee, and A. Vetro, "Use of two-dimensional deformable mesh structures for video coding, part II - the analysis problem and a region-based coder employing an active mesh representation," IEEE Transactions on Circuits and Systems for Video Technology, vol. 6, pp. 647--659, Dec. 1996.

No context found.

Y. Wang and O. Lee, "Use of two-dimensional deformable mesh structures for video coding, part I --- the synthesis problem: mesh-based function approximation and mapping," Dec. 1996.

No context found.

Y. Wang, O. Lee, and A. Vetro, "Use of two-dimensional deformable mesh structures for video coding, part ii-the analysis problem and a region-based coder employing an active mesh representation," in IEEE Transactions on circuits and systems for video technology, vol. 6, pp. 647--659, dec 1996.

No context found.

Y. Wang and O. Lee, "Use of two-dimensional deformable mesh structures for video coding, part i-the synthesis problem: mesh-based function approximation and mapping," in IEEE Transactions on circuits and systems for video technology, vol. 6, pp. 636--646, december 1996.

No context found.

Y. Wang, O. Lee, and A. Vetro, "Use of two-dimensional deformable mesh structures for video coding, Part II---The analysis problem and a region-based coder employing an active mesh representation," IEEE Trans. Circuits Syst. Video Technol., vol. 6, pp. 647--659, Dec. 1996.

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC