• PDF / 24,159,331 Bytes
• 244 Pages / 612 x 792 pts (letter) Page_size
• 16 Downloads / 234 Views

DOWNLOAD

REPORT

---

406

M

developed for cardiac echographic images. Objective of this algorithm is to define a region of interest in which measurements (e.g. image intensity) can lead, after appropriate interpretation, to the estimation of important cardiovascular parameters without the need for invasive techniques. In addition to the aforementioned techniques, numerous other algorithnis for applications of segmentation to specialized medical imagery interpretation exist. See: Segmentation of images and video

References 1. V. Grau, A.U.J. Mewes, M. Alcaniz, R. Kikinis, and S.K. Warfield, "Improved watershed transform for medical image segmentation using prior information," IEEE Transactions on Medical Imaging, Vol. 23, No. 4, April 2004, pp. 447-458. 2. M.W. Woolrich, T.E.J. Behrens, C.F. Beckmann, and S.M. Smith, "Mixture models with adaptive spatial regularization for segmentation with an application to FMRI data," IEEE Transactions on Medical Imaging, Vol. 24, No. 1, January 2005, pp. 1-11. 3. M. Mischi, A.A.C.M. Kalker, and H.H.M. Korsten, "Cardiac image segmentation for contrast agent video densitometry," IEEE Transactions on Biomedical Engineering, Vol. 52, No. 2, February 2005, pp. 277-286.

MESH, 3D Definition: polygons.

Mesh is a 3D object representation consisting of a collection of vertices and

The 3D object representation can be a polygon mesh, which consists of a collection of vertices and polygons that define the shape of an object in 3D (Figure 1). To benefit from current 3D graphic cards hardware acceleration polygon meshes usually contain only triangles because the hardware is optimized for triangle mesh computation.

Figure 1. Polygon mesh corresponding to a human face.

Encyclopedia of Multimedia

407

Polygon meshes, as a 3D surface representation with 3D points and connectivity, have initially been considered for compression in a static way. The contributions were focused on compression of vertex positions and connectivity. Static mesh coding, exploiting spatial dependencies of adjacent polygons, is also currently part of MPEG-4. The MPEG-4 computer graphics part AFX (Animation Framework extension) offers a tool called AFX Interpolator Compression which allows the compression of such a linear keyframe animation. Animated sequences of 3D objects stem from a number of different applications, starting with pure virtual Computer Graphics objects that deform over time. One of the newer application fields includes mixed-reality object reconstruction, where natural images are captured to reconstruct 3D objects with natural appearance for virtual environments. Those objects are referred to as "3D video objects" or 3DVOs, a term that describes a new representation format for visual media. It allows free navigation around real world dynamic objects by choosing arbitrary viewpoints and viewing directions similar to navigation in virtual-reality environments. 3DVOs are an extension of classical computer graphic objects towards representing motion and appearance of real world moving objects. Similar to animated syntheti