On combining shape from silhouette and shape from structured light (original) (raw)
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3D modeling of archaeological vessels using shape from silhouette
3dim, 2001
An algorithm for the automatic construction of a 3 0 model of archaeological vessels is presented. In archeology the determination of the exact volume of arbitrary vessels is of importance since this provides information about the manufacturer and the usage of the vessel. To acquire the shape of objects with handles in 3d is complicated, since occlusions of the object's su$ace are introduced by the handle and can only be resolved by taking multiple views. Therefore, the 3d reconstruction is based on a sequence of images of the object taken from different viewpoints. The object's silhouette is the only feature which is extracted from an input image. Images are acquired by rotating the object on a turntable in front of a stationary camera. The algorithm uses an octree representation of the model, and builds this model incrementally, by pelforming limited processing of all input images for each level of the octree. Beginning from the root node at the level 0 a rough model of the object is obtained quickly and is re$ned as the processed level of the octree increases. Results of the algorithm developed are presented for both synthetic and real input images. 5 1 0-7695-0984-3101 $10.00 0 2001 IEEE Authorized licensed use limited to: Drexel University. Downloaded on February 15,2010 at 13:03:24 EST from IEEE Xplore. Restrictions apply.
Pattern Recognition, 2002
An algorithm for the automatic construction of a 3d model of archaeological vessels using two different 3d algorithms is presented. In archeology the determination of the exact volume of arbitrary vessels is of importance since this provides information about the manufacturer and the usage of the vessel. To acquire the 3d shape of objects with handles is complicated, since occlusions of the object's surface are introduced by the handle and can only be resolved by taking multiple views. Therefore, the 3d reconstruction is based on a sequence of images of the object taken from different viewpoints with two different algorithms; shape from silhouette and shape from structured light. The output of both algorithms are then used to construct a single 3d model. Results of the algorithm developed are presented for both synthetic and real input images.
3D Modeling in Profile-Based Archeological Object Reconstruction
3D measurement and modeling has helped archeology in a lot of cases. The digital and numeric nature of the technique enables the users to manipulate, reconstruct, and conduct other analyses otherwise rendered destructible to the object. A digital analysis would also mean less time and energy compared to conventional, manual methods. In this paper, a shard of an antique plate unearthed in Kota Piring Palace, Biram Dewa Island, Indonesia is reconstructed by means of photogrammetry. A profile of the resulting 3D model is extracted, and a hypothetical reconstructed 3D model is created by rotating the said profile. The resulting 3D model can then be used for various analyses, as well as physical reconstructions (e.g. by means of 3D printing technology).
Reconstruction of Archaeological Finds using Shape from Stereo and Shape from Shading
We propose a novel algorithmic framework for the refinement of sparse 3D models using shape from shading. Starting from an initial model obtained by shape from stereo we use a global optimization scheme in order to refine the surface. The constraints we use are based on the shading in the image, the initial 3D points obtained by stereo and the smoothness of the surface. In contrast to many previous approaches that assume that the photometric properties of the scene are known we iteratively update the light source direction and several parameters of the reflectance map. A careful choice of several boundary conditions on the reflectance map, the use of a multigrid scheme, the discretization of the object on a pseudo-hexagonal grid and the frequent switching between different refinement modules allows us to optimize the highly underconstrained problem. We provide results on synthetic data and reconstruction examples of frieze parts from an excavation site in Sagalassos (Turkey).
Automated extraction of profiles from 3d-models of archaeological fragments
Proceedings of the CIPA 2003 XIXth International …, 2003
Motivated by the requirements of the present archaeology, we have been developing an automated archivation system for archaeological classification and reconstruction of ceramics. Our system works with the profile of an archaeological fragment, which is the cross-section of the fragment in the direction of the rotational axis of symmetry. Ceramic fragments are recorded automatically by a 3D-measurement system based on structured light. The input data for the estimation of the profile is a set of points produced by the acquisition system. The profile is used to reconstruct the original pot. Our approach consists of several steps, starting by calculating the proper orientation, which describes the exact positioning of the fragment on the original vessel. Next the profile line is computed and several measurements, like the diameter and height of the vessel. After evaluating the profile line a virtual pot is reconstructed. The performance of the proposed algorithm was tested on real data and the results are presented in this paper.
An antique 300-year old wooden globe, preserved in the National Museum of Switzerland, had to be copied physically for delivery to another party. For this purpose a 3D computer model had to be generated. A structured light system and two digital frame cameras were employed, and the generated datasets were integrated to obtain both the geometry and the texture of the model. This paper reviews the whole workflow from data acquisition to the final geometrical surface and textural information. The results of the processes are presented and discussed and some conclusions regarding the exploitation of the two mentioned techniques are given.
There exist many archeological objects which are broken in pieces. It is always important to find the neighbouring pieces so that different parts of the object can be put together and the original object reconstructed. Direct evaluation of broken objects has several disadvantages, such as being difficult and time-consuming. As an alternative, indirect techniques like photogrammetry and laser scanning can be applied, in which measurements of object pieces can be made and the overall shape of the object constructed by inspection of the relation between models of object parts. When compared with direct techniques, such methods enjoy being fast and non-contact so leading to the increased safety of the objects under reconstruction. In this project, photogrammetry is used to extract edges of the broken parts. The mathematical relations between the edges are then examined, the neighbouring parts are found and the model of the object is formed. This paper studies various parameters each of which defines some mathematical relation between parts of an object. The experiments carried out show that the radius of curvature is a suitable parameter which can be used to find the neighbouring pieces of the modelled object. The results show enough accuracy for 3D modelling of the object with the specified dimensions in our experiments. But in order to verify the validity of this method, it should be applied to a wide range of archaeological objects.
Shape from Silhouette Under Varying Lighting and Multi-viewpoints
2011 Canadian Conference on Computer and Robot Vision, 2011
We present a new segmentation method for visual hull (VH) reconstruction from an image sequence. The camera moves on a hemisphere around an object set on a turntable with complex and unknown background. Even though the background is assumed to be constant, it cannot be modeled from all possible viewpoints. A series of images of a moving object under different lighting conditions are captured and analyzed. In this analysis, information from space, time and light domains are fused into an MRF framework. The method is validated by VH reconstruction of challenging objects with different optical properties.
3D MODELING OF CULTURAL HERITAGE OBJECTS WITH A STRUCTURED LIGHT SYSTEM
Mediterranean Archaeology and Archaeometry, 2012
3D modeling of cultural heritage objects is an expanding application area. The selection of the right technology is very important and strictly related to the project requirements, budget and user’s experience. The triangulation based active sensors, e.g. structured light systems are used for many kinds of 3D object reconstruction tasks and in particular for 3D recording of cultural heritage objects. This study presents the experiences in the results of two such projects in which a close-range structured light system is used for the 3D digitization. The paper includes the essential steps of the 3D object modeling pipeline, i.e. digitization, registration, surface triangulation, editing, texture mapping and visualization. The capabilities of the used hardware and software are addressed. Particular emphasis is given to a coded structured light system as an option for data acquisition. KEYWORDS: active sensors, 3D point cloud, scanning, registration, surface triangulation, visualization
Silhouette-based 3D Model Reconstruction from Multiple Images
The goal of this study is to investigate the reconstruction of 3D graphical models of real objects in a controlled imaging environment and present the work done in our group based on silhouette-based reconstruction. Although many parts of the whole system have been well-known in the literature and in practice, the main contribution of the paper is that it describes a complete, end-to-end system explained in detail. Based on a multi-image calibration method, an algorithm to extract the rotation axis of a turn-table has been developed. Furthermore, this can be extended to estimate robustly the initial bounding volume of the object to be modeled. The disadvantages of the silhouette-based reconstruction can be removed by an algorithm using photoconsistency. This algorithm has a simpler visibility check, and it eliminates the selection of threshold existing in similar algorithms. Besides, in order to construct the appearance, we use the concept of particles. The reconstruction results are shown both on real world and synthetic objects.