Visualization of 3D variable in time object based on data gathered by active measurement system P. GARBAT *1 and M. KUJAWIÑSKA 2 1 Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, 75 Koszykowa Str., 00-662 Warsaw, Poland 2 Institute of Micromechanics and Photonics, Warsaw University of Technology, 8 Œw. Andrzeja Boboli Str., 02-525 Warsaw, Poland The recent needs of analysis and visualization of variable in time real 3D objects in many applications require development of new approach towards combining rapid 3D shape acquisition and the methodology of data processing in order to perform visualization and analysis of real 3D dynamic objects. In this paper, the general concept of visualization system of data gath- ered by means of optical 4D (x,y,z,t) shape measurement system is presented. The concept of a virtual camera, as the mean for interactive object visualization is introduced. The experimental results for processing of simulated and real variable in time 3D object are presented and discussed. The directions of future works focused on full implementation of the concept are introduced. Keywords: 3D object visualization, 3D data processing. 1. Introduction Recently one of the biggest challenges in multimedia tech- nologies is to create a fully interactive, remote 3D visual- ization system [1]. This requires gathering real data about static or dynamic 3D objects and scenes and delivering them to a remote visualization system. In those systems, the observer has the possibility of selection of a vantage point from which to view the image and interact with ob- jects. Currently, different systems provide limited 3D inter- active content [1], triangle mesh or image based and video based 3D visualization. The still object imagery is based alternatively on digi- tal-image set or 3D polygonal models. The digital-image set method [2] captures a large set of digital images of a given object viewed from different viewpoint. The user in- tuitively selects between these views. View controls in- clude panning and rotation along the horizontal and vertical axes, further the 3D illusion. However, this method is based on 2D images and in order to provide truly realistic 3D imaging the system requires numerous views and there- fore the file size become unmanageably large. Still an ob- ject imagery method uses computer graphics algorithms or experimental-optical data acquisition and numerical con- version methods [3] to build 3D polygonal models of 3D objects, then pastes texture maps onto these objects’ sur- faces. This 3D polygonal model can be rendered from arbi- trary viewpoints and file size remains relatively small. However, the numerical models often look artificial or plastic because the texture maps and limiting lighting ef- fects do not accurately represent the surface appearance from all angles. That is the reason why the experimental methods of gathering the data about 3D objects in the form of cloud of co-ordinate points have become so popular [4]. Main advance of 3D polygonal models is the possibility of appearance modification. However, recently, the visualization of 3D still objects is not sufficient. The real challenge is to create 3D video [1]. The most recent attempts focus on creating a true 3D video in which a viewer can move through the captured scene in both time and space [1]. For this type of a sys- tem, the cameras are spaced around the capture space and calibrated precisely. Because the scene’s 3D structure is known, the system can combine multiple live or pre-re- corded 3D video streams in real time. These newest pro- jects are based on digital images and depth map informa- tion. Rendering a virtual view from multiple 3D video streams requires warping the multiple camera views to a single virtual view using the depth maps and camera poses [5]. The other new system uses the video based ac- quisition for real time 3D polygonal object geometry re- construction [6]. The essential constrain in such scenario is that the foreground content is physically separated from the background which does not move and change colour or brightness. Because the quality of 3D geometry recon- struction in this type of systems is not efficient, the video acquisition is replaced with active shape measurement methods [7]. 97 Opto-Electron. Rev., 16, no. 1, 2008 OPTO-ELECTRONICS REVIEW 16(1), 97–104 DOI: 10.2478/s11772-007-0041-5 * e-mail: pgarbat@elka.pw.edu.pl Image Processing Technology