3-D Reconstruction

In this paper, we present a practical vision based Simultane-ous Localization and Mapping (SLAM) system for a highly dynamic environment. We adopt a multibody Structure from Motion (SfM) approach, which is the generalization of classical SfM to dynamic scenes with multiple rigidly mov-ing objects. The proposed framework of multibody visual SLAM allows choosing between full 3D reconstruction or simply tracking of the moving objects, which adds flexibil-ity to the system, for scenes containing non-rigid objects or objects having insufficient features for reconstruction. The solution demands a motion segmentation framework that can segment feature points belonging to different motions and maintain the segmentation with time. We propose a re-altime incremental motion segmentation algorithm for this purpose. The motion segmentation is robust and is capa-ble of segmenting difficult degenerate motions, where the moving objects is followed by a moving camera in the same direction. This robu...

ToF cameras are new instruments based on CCD/CMOS sensors which measure distances instead of radiometry. The resulting point clouds show the same properties (both in terms of accuracy and resolution) of the point clouds acquired by means of traditional LiDAR devices. ToF cameras are cheap instruments (less than 10.000 €) based on video real time distance measurements and can represent an interesting alternative to the more expensive LiDAR instruments. In addition, the limited weight and dimensions of ToF cameras allow a reduction of some practical problems such as transportation and on-site management. Most of the commercial ToF cameras use the phase-shift method to measure distances. Due to the use of only one wavelength, most of them have limited range of application (usually about 5 or 10 m). After a brief description of the main characteristics of these instruments, this paper explains and comments the results of the first experimental applications of ToF cameras in Cultural Her...

In this work, the integration between data provided by Time-of- light cameras and a multi-image matching technique for metric surveys of architectural elements is presented. The main advantage is given by the quickness in the data acquisition (few minutes) and the reduced cost of the instruments. The goal of this approach is the automatic extraction of the object breaklines in a 3D environment using a photogrammetric process, which is helpful for the final user exigencies for the reduction of the time needed for the drawing production. The results of the performed tests on some architectural elements will be reported in this paper.

The aim of this study is to build a Web-based virtual tour system, focused at the presentation of archaeological sites. The proposed approach is comprised of powerful techniques such as multiview 3D reconstruction, omnidirectional viewing based on panoramic images, and their integration with GIS technologies. In the proposed method, the scene is captured from multiple viewpoints utilizing off-the-shelf equipment and its 3D structure is extracted from the acquired images based on stereoscopic techniques. Color information is added to the generated 3D model of the scene and the result is converted to a common 3D scene modeling format. The 3D models and interactive virtual tour tools such as 360° viewing are integrated with GIS technologies in which the excavation site plans can be added as detailed raster overlays. * Corresponding author.

Image segmentation has traditionally been thought of us a low/mid-level vision process incorporating no high level constraints. However, in complex and uncontrolled environments, such bottom-up strategies have drawbacks that lead to large misclassification rates. Remedies to this situation include taking into account (1) contextual and application constraints, (2) user input and feedback to incrementally improve the performance of the system. We attempt to incorporate these in the context of pipeline segmentation in industrial images. This problem is of practical importance for the 3D reconstruction of factory environments. However it poses several fundamental challenges mainly due to shading. Highlights and textural variations, etc. Our system performs pipe segmentation by fusing methods from physics-based vision, edge and texture analysis, probabilistic learning and the use of the graph-cut formalism

In Thailand, there are several types of (tangible) cultural heritages. This work focuses on 3D modeling of the heritage objects from multi-views images. The images are acquired by using a DSLR camera which costs around $1,500 (camera and lens). Comparing with a 3D laser scanner, the camera is cheaper and lighter than the 3D scanner. Hence, the camera is available for public users and convenient for accessing narrow areas. The acquired images consist of various sculptures and architectures in Wat-Pho which is a Buddhist temple located behind the Grand Palace (Bangkok, Thailand). Wat-Pho is known as temple of the reclining Buddha and the birthplace of traditional Thai massage. To compute the 3D models, a diagram is separated into following steps; <i>Data acquisition</i>,…

Different institutions worldwide, such as economic, social and political, are relying increasingly on the communication technology to perform a variety of functions: holding remote business meetings, discussing design issues in product development, enabling consumers to remain connected with their families and children, and so on. In this environment, where geographic and temporal boundaries are shrinking rapidly, electronic communication medium are playing an important role. With recent advances in 3D sensing, computing on new hardware platforms, high bandwidth communication connectivity and 3D display technology, the vision of 3D video-teleconferencing and of tele-immersive experience has become very attractive. These advances lead to tele-immersive communication systems that enable 3D interactive experience in a virtual space consisting of objects born in physical and virtual environments. This experience is achieved by fusing real-time color plus depth video of physical scenes from multiple stereo cameras located at different geographic sites, displaying 3D reconstructions of physical and virtual objects, and performing computations to facilitate interactions between objects. While tele-immersive (TI) systems have been attracting a lot of attention these days, the advantages of enabled interactions and delivered 3D content for viewing as opposed to current 2D high definition video have not been evaluated. In this paper, we study the effectiveness of three different types of communication media on remote collaboration in order to document the pros and cons of new technologies such as TI. The three communication media include 3D video tele-immersive, 2D video Skype and face-to-face used in a collaborative environment of a remote product development scenario. Through a study done over 90 subjects, we discuss the strengths and weaknesses of different media and propose a scope for improvement in each of them.

... Camera calibration is the first step towards computational computer vision. ... light emitter) permits crossing both optical rays to get the metric position of the 3D points [ 4 , 5 ... If these measurements are stored, a temporal analysis allows the handler to determine the trajectory of the ...

Creating convincing representations of humans is a fundamental problem in both traditional arts and modern media. In our digital world, virtual avatars allow us to simulate and render the human body for a variety of applications, including movie production, sports, human-computer interaction, and medical sciences. However, capturing digital representations of a person’s shape, appearance, and motion is an expensive and time-consuming process which usually requires a lot of manual adjustments.

This paper presents the first prototype of an interactive visualisation framework specifically designed for presenting geographical information in both indoor and outdoor environments. The input of our system is ESRI Shapefiles which represent 3D building geometry and landuse attributes. Participants can visualise 3D reconstructions of geographical information in real-time based on two visualisation clients: a mobile VR interface and a tangible AR interface. To prove the functionality of our system an educational application specifically designed for university students is illustrated with some initial results. Finally, our conclusions as well as future
work are presented.

Potential applications of volume rendering in musculo-skeletal disorders Three dimensional imaging is increasingly important for evaluation of anatomic relationships and extent of disease, for treatment planning and for follow-up evaluation. The volume rendering technique allows creation of accurate 3D images that can be used for several clinical applications especially in musculo-skeletal disorders such as evaluation of tumors or fractures. This