This paper presents an innovative 3D reconstruction of ancient fresco paintings through the real-time revival of their fauna and flora, featuring groups of virtual animated characters with artificial-life dramaturgical behaviours in an immersive, fully mobile augmented reality (AR) environment. The main goal is to push the limits of current AR and virtual storytelling technologies and to explore the processes of mixed narrative design of fictional spaces (e.g. fresco paintings) where visitors can experience a high degree of realistic immersion. Based on a captured/real-time video sequence of the real scene in a video-see-through HMD set-up, these scenes are enhanced by the seamless accurate real-time registration and 3D rendering of realistic complete simulations of virtual flora and fauna (virtual humans and plants) in a real-time storytelling scenario-based environment. Thus the visitor of the ancient site is presented with an immersive and innovative multi-sensory interactive trip to the past. Copyright © 2005 John Wiley & Sons, Ltd.

www.2d3.com The field of special effects in post-production has undergone an exciting period of innovation in recent years. There has been a surge in demand for camera tracking or “matchmoving”. A number of companies have built manual matchmoving products, and more recently automatic matchmovers have come to market. We will discuss the nature of the problems that the industry requires solved, and the products that have attempted to deliver solutions. Complex vision algorithms have inevitable failure modes, and this raises several issues including the relationship between automatic and manual solutions and the performance of published algorithms. 1

Recently 3 algorithms for registration of multiple partially overlapping point sets have been published by Pennec [11], Stoddart & Hilton [12] and Benjemma & Schmitt [1]. The problem is of particular interest in the building of surface models from multiple range images taken from several viewpoints. In this paper we perform a comparison of these three algorithms with respect to cpu time, ease of implementation, accuracy and stability. 1 Introduction To appear at British Machine Vision Conference, Nottingham, UK. (1999). Several authors have considered the problem of building complete surface models of complex objects using range images taken from several views [2, 4, 5, 6]. Since the viewpoints (or object poses) are usually not known it is necessary to register the surfaces taken from various views prior to fusion [8]. In the case of 2 views the iterated closest point algorithm (ICP) [3] may be used to register surfaces. This algorithm requires a solution to the 3D point set registrat...

The problem of hip joint centre location using optical markers located on the skin is addressed. We present a novel computational technique which can recover joint centre location based solely on the marker measurements. In addition a quantitative estimate of the uncertainty in joint centre location is obtained. We also present some preliminary experimental validation of the technique on a rigid jointed object.

The ModelMaker [8] is a commercially available hand-held laser scanner mounted on an articulated arm. In this paper we present results from postprocessing of ModelMaker data and a novel technique for recalibrating the data while postprocessing. We demonstrate significant noise reduction of the resulting surface data. These results suggest that lower specification, possibly cheaper arms, may be used to get results as good as those currently obtained with high specification arms. 1 Introduction Traditional range scanners are mounted on XY platforms or scan objects mounted on rotating platforms. These scanners have the limitation that they cannot capture complex geometry in a single scan. Recently 3D Scanners [8] has produced a sensor called ModelMaker that facilitates the capture of more complex geometries. The sensor is based on a small hand-held laser striper mounted on an articulated arm that measures in real time the position and orientation of the striper. R. B. Fisher et a...

Thermochromic paint, paint that changes colour according to the maximum temperature it has experienced, has a variety of uses within the automotive industry. Currently interpretation is performed manually by a human operator. This paper addresses the task of automatic interpretation, specifically addressing problems relating to feature space ambiguity. We derive a cost function to overcome these problems and utilise this within a simulated annealing framework. The method was developed using synthetic data which models the causes of ambiguity, and results are presented for real image data derived from paint-coated industrial parts.

In previous work (Saminathan et al. (1997)) we have developed a G/sup 1/ continuous arbitrary topology deformable surface called 'slime'. Surface reconstruction was shown for point clouds and volumetric field functions within a conventional snake optimisation approach. Hoppe (1995) has proposed an efficient alternative based on a local conjugate gradient optimisation and local mesh editing. We have been able to apply this framework to the slime representation. In this paper we present a technique using local editing operations on the arbitrary topology control mesh. In this way we can produce a surface reconstruction at multiple resolutions. In our results we show how a complex surface of 33000 planar faces can be compressed into 451 vertices (or curved patches) for very little loss of visual quality.

Accurate registration of surfaces is a common problem in computer vision. Several algorithms exist to refine an approximate value for the pose to an accurate value. They are all more or less variants of the Iterated Closest Point algorithm of Besl and McKay (1992). Up to now the problem of determining the uncertainty in the pose estimate thus obtained has not been addressed in detail. In this paper we present a framework in which to quantify the uncertainty in pose. We introduce a new parameter called the registration index to give a simple means of quantifying the pose errors one might expect when registering a particular shape. 1 Introduction To appear at British Machine Vision Conference, Edinburgh, UK. (1996). The registration of surfaces and curves can be broken down into two separate tasks. A matching task in which an approximate estimate of the pose is obtained. This might also involve a large database of model shapes. Then a registration task in which an accurate po...

A new surface based approach to implicit surface polygonisation is introduced. This is applied to the reconstruction of 3D surface models of complex objects from multiple range images. Geometric fusion of multiple range images into an implicit surface representation was presented in previous work. This paper introduces an efficient algorithm to reconstruct a triangulated model of a manifold implicit surface, a local 3D constraint is derived which defines the Delaunay surface triangulation of a set of points on a manifold surface in 3D space. The 'marching triangles' algorithm uses the local 3D constraint to reconstruct a Delaunay triangulation of an arbitrary topology manifold surface. Computational and representational costs are both a factor of 3-5 lower than previous volumetric approaches such as marching cubes.

The free-form surface matching problem is important in several practical applications, such as reverse engineering. An accurate, robust and fast solution is, therefore, of great significance. Recently genetic algorithms have attracted great interest for their ability to robustly solve hard optimization problems. In this work we investigate the performance of such an approach for finding the initial guess of the transformation, a translation and a rotation, between the object and the model surface. This is followed by a local gradient descent method, such as iterative closest point, to refine the estimate. Promising results are demonstrated on accurate real data.

Registering 3D point sets subject to rigid body motion is a common problem in computer vision. The optimal transformation is usually specified to be the minimum of a weighted least squares cost. The case of 2 point sets has been solved by several authors using analytic methods such as SVD. In this paper we present a numerical method for solving the problem when there are more than 2 point sets. Although of general applicability the new method is particularly aimed at the multiview surface registration problem. To date almost all authors have registered only two point sets at a time. This approach discards information and we show in quantitative terms the errors caused.

Probabilistic Relaxation with product support has been shown to have advantages over 'traditional ' probabilistic relaxation. However it is less well understood in the sense that a cost function is not known. In this paper we present a cost function. This greatly improves our understanding of probabilistic relaxation with product support, and also leads us to propose a new class of probabilistic relaxation algorithms. We investigate two applications. 1

Deformable surfaces have many applications in surface reconstruction, tracking and segmentation of range or volumetric data. Many existing deformable surfaces connect control points in a predefined and inflexible way. This means that the surface topology is fixed in advance, and also imposes severe limitations on how a surface can be described. For example a rectangular grid of control points cannot be evenly distributed over a sphere, and singularities occur at the poles. In this paper we introduce a new (G 1 continuous) deformable surface. In contrast to other methods this method can represent a surface of arbitrary topology, and do so in an efficient way. The method is based on a generalization of biquadratic B-splines, and has a comparable computational cost to methods based on traditional tensor product B-splines. 1

Range images may be used for a variety of applications in object recognition, inspection and reverse engineering. In many of these applications it is important to obtain good estimates of the local surface curvature. Good curvature estimates require good derivative estimates, but the estimation of derivatives from sampled data is highly susceptible to noise. In this paper, we introduce a new way of characterizing range data by a single parameter. From this characterization we show how to make an optimal choice of whatever parameters there are in a particular derivative estimation method, and obtain an estimate of the error one might expect. Finally, we show how the analysis may be applied to measuring derivatives on a cylinder.