Point-Based Graphical Objects for the MPEG-4 SNHC Standard
We have proposed new syntax and semantics for the MPEG-4 standard to allow high-quality rendering of point-based graphical representations. Our contribution was conditionally accepted to be included in the MPEG-4 SNHC (Synthetic Natural Hybrid Coding) Animation Framework eXtension (AFX).
Background & Objective: In recent years we have witnessed a dramatic increase in the polygonal complexity of computer graphics models. As a result, the average size of a rendered polygon is less than the size of a screen pixel. The processing of many small triangles leads to bandwidth bottlenecks and excessive rasterization requirements. This trend, combined with the associated overhead of managing, processing, and manipulating polygonal-mesh connectivity information, has led many leading researchers to question the future usefulness of polygons as the fundamental graphics primitive.
At the same time, advances in 3D digital photography and scanning technology have spawned systems that acquire both the geometry and appearance of complex, real-world objects. A major application for such 3D range cameras is the ready creation of digital 3D content, including some of the most visually stunning models to date. One of the challenges with these techniques is the huge volume of point samples they generate. These points constitute discrete building blocks of 3D object geometry and appearance much as pixels are the digital elements for images.
For these reasons, point primitives have experienced a major renaissance in recent years. Since then, considerable research has been devoted to the efficient representation, modeling, processing, and rendering of point-sampled geometry. Point primitives can be efficiently rendered and displayed in high quality, and novel algorithms for advanced shape modeling and digital geometry processing are entirely based on point samples. These efforts have spawned a new field called point-based computer graphics. The purpose of our research is to include point-based objects in the MPEG-4 SNHC standard.
Technical Discussion: For a dynamic point based object representation, e.g., 3D video fragments, we extend certain nodes in the existing MPEG-4 AFX format with additional attributes, such as normal and elliptical splat information. For a static point based representation, e.g., surfels, novel geometric attributes are specified through the use of MPEG-4 vector and normal nodes. By using existing nodes for normal data we can directly use the quantization procedure of MPEG-4, if necessary.
Publications:
Technology Areas:
Digital Video
Graphics
Modification Date: September 12, 2007