Álvaro Segura

Interactive visualization of volumetric data with WebGL in real-time

This article presents and discusses the implementation of a direct volume rendering system for the Web, which articulates a large portion of the rendering task in the client machine. By placing the rendering emphasis in the local client, our system takes advantage of its power, while at the same time eliminates processing from unreliable bottlenecks (e.g. network). The system developed articulates in efficient manner the capabilities of the recently released WebGL standard, which makes available the accelerated graphic pipeline (formerly unusable). The dependency on specially customized hardware is eliminated, and yet efficient rendering rates are achieved. The Web increasingly competes against desktop applications in many scenarios, but the graphical demands of some of the applications (e.g. interactive scientific visualization by volume rendering), have impeded their successful settlement in Web scenarios. Performance, scalability, accuracy, security are some of the many challenges that must be solved before visual Web applications popularize. In this publication we discuss both performance and scalability of the volume rendering by WebGL ray-casting in two different but challenging application domains: medical imaging and radar meteorology.

Interactive Urban and Forest Fire Simulation with Extinguishment Support

Fires and other related disasters provoke great destruction of high valuable environments and economical losses, especially when they are located in urban areas. In this work, we present a combined urban and forest fire spreading algorithm to be used in real time and interactive virtual simulations. The algorithm is pedagogical oriented and its purpose is not focused in achieving precise results that could be used to predict the fire evolution. The main objective is to obtain a fast, interactive and quasi-realistic virtual simulation to be used in the simulation of virtual scenarios where firefighters and controllers will be trained. The algorithm supports the main variables involved in the fire spreading (slope and wind) and the radiation effect. An additional method has been added to extinguish the fire.

High quality parametric visual product configuration systems over the web

Visual product configuration systems over the Web promise to significantly improve the core business processes of product and service companies. Such systems allow clients to remotely configure products by interactively selecting a set of options and instantly visualizing their resulting 3D representations on-line. This type of functionality is still very rare on the Web and the few provided solutions are typically far from being satisfying for highly competitive companies. The main limitations of current solutions are mainly due to typical constraints imposed by the interactive exploration of 3D models in a web browser.In this paper we propose an advanced graphical system for visual configuration of 3D products for the Web. We mainly focused on reducing the perceived difference between the 3D representation of the product and the physical product. The viewer performance was increased, supporting new visual features and effects --scenes containing multiple mirrors are supported--, and new levels of methods of interaction added. We demonstrate our approach in a real-world example with the implementation of a complete Web-based visual configuration for a manufacturer of lift cabins.

Volume Ray Casting in WebGL

Real-time 3D computer graphics systems usually handle surface description models (i.e. B-Rep representations) and use surface rendering techniques for visualization. Common 3D model formats such as VRML, X3D, COLLADA, U3D (some intended for the Web) are based entirely on polygonal meshes or higher order surfaces. Real-time rendering of polygon models is straightforward and raster render algorithms are implemented in most graphics accelerating hardware. For many years several rendering engines, often via installable browser plug-ins, have been available to support 3D mesh visualization in Web applications.

Interactive and stereoscopic hybrid 3d viewer of radar data with gesture recognition

This work presents an interactive and stereoscopic 3D viewer of weather information coming from a Doppler radar The hybrid system shows a GIS model of the regional zone where the radar is located and the corresponding reconstructed 3D volume weather data To enhance the immersiveness of the navigation, stereoscopic visualization has been added to the viewer, using a polarized glasses based system The user can interact with the 3D virtual world using a Nintendo Wiimote for navigating through it and a Nintendo Wii Nunchuk for giving commands by means of hand gestures We also present a dynamic gesture recognition procedure that measures the temporal advance of the performed gesture postures Experimental results show how dynamic gestures are effectively recognized so that a more natural interaction and immersive navigation in the virtual world is achieved.

Visual Processing of Geographic and Environmental Information in the Basque Country: Two Basque Case Studies

The Basque Meteorology Agency is conducting an initiative to improve the collection, management and analysis of weather information from a large array of sensing devices. This chapter presents works carried out in this context proposing the application of 3D geographical visualization and image processing for the monitoring of meteorological phenomena. The tools described allow users to analyze visually the state of the atmosphere and its interaction with the topography, and process live outdoor images to automatically infer weather conditions. This kind of systems can be applied in the surveillance of other environmental events and enable better decision making for several purposes, including important issues related with environmental security.

Interaction and ergonomics issues in the development of a mixed reality construction machinery simulator for safety training

We present the work on a simulator of construction machinery developed to train workers in their safe use. The simulation setup consists of a real versatile cabin placed on a motion platform in order to provide a realistic interaction with the system and a stereoscopic augmented reality system for visualization. We present some insights into the mixed reality setup we used for complex construction machines and discuss the interaction and usability problems that have arisen during its development and testing. Visualization has been implemented as a chroma-key-based mixed reality system, which combines the 3D virtual environment, the real cabin interior, and some superimposed messages to the user. As a result of our experience, we describe the main problems encountered from a usability and ergonomics point of view.

Mesh segmentation and texture mapping for dimensional inspection in Web3D

Traditionally, the data generated by industrial metrology software is stored as static reports that metrology experts produce for engineering and production departments. Nevertheless, industry demands new approaches that provide ubiquitous and real time access to overall geometry, manufacturing and other data. Web3D technologies can help to improve the traditional metrology methods and offer new ways to convey this information in web-based continuous friendly manner. However, enriched point clouds may be massive, thus presenting transmission and display limitations. To partially overcome these limitations, this article presents an algorithm that computes efficient metrology textures, which are then transferred and displayed through Web3D standards. Texture coordinates are computed only once for the reference CAD mesh on the server using in-house thermal-based segmentation and Hessian-based parameterization algorithms. The metrology data is then encoded in a texture file, which becomes available instantly for interactive visual inspection through the Web3D platform.

Virtual Reality Interfaces Applied to Web-Based 3D E-Commerce

E-commerce is well established on today’s Internet and has created its own set of techniques for performing and optimizing sales. Traditional shops on the other hand provide a physical space in which decoration and space are relevant. In this paper we present innovative interfaces that join the concepts of real shops and on-line e-commerce in a Web-based virtual reality platform.The idea involves making the e-shopping experience more intuitive, closer to the experience of visiting a real shop, and providing on-line 3D interfaces for the entire process from shop design and product placement to customer experience analysis. We researched traditional marketing and sales techniques and the way they can be transferred to 3D virtual reality environments. Web 3D technologies allow us to implement interactive virtual worlds on the Web, accessible for everyone over different platforms and without special applications or plug-ins.Copyright

Steel Tube Cross Section Geometry Measurement by 3D Scanning.

In this paper we describe a system aimed at obtaining several geometric measures from seamless steel tubes representative of their manufacturing quality. Traditionally, these measurements are taken manually using calipers and similar tools, which are error-prone and have low reproducibility. We introduce a system based on 3D scanning and computational geometry. Scanning adds surface noise and may leave small undetectable gaps depending on surface properties, and the tube itself may have small defects not representative of the overall tube shape. Also, processing high resolution scans containing millions of points can be too time consuming. Thus, special algorithms are needed to make the problem tractable and produce representative measures in a reasonable time.