Manuel E. Loaiza

A Case Study on the Implementation of the 3C Collaboration Model in Virtual Environments

Throughout the years many studies have explored the potential of Virtual Reality (VR) technologies to support collaborative work. However few studies looked into CSCW (Computer Supported Cooperative Work) collaboration models that could help VR systems improve the support for collaborative tasks. This paper analyzes the applicability of the 3C collaboration model as a methodology to model and define collaborative tools in the development of a collaborative virtual reality application. A case study will be presented to illustrate the selection and evaluation of different tools that aim to support the actions of communication, cooperation and coordination between users that interact in a virtual environment. The main objective of this research is to show that the criteria defined by the 3C model can be mapped as a parameter for the classification of interactive tools used in the development of collaborative virtual environments.

A VR Framework for Desktop Applications

The emergence of cheaper technologies for immersive environments has increased considerably the interest on applications of Virtual Reality (VR). However, currently available VR frameworks force user applications to be developed specifically for them. This increases the cost of converting an existing graphical application to virtual reality environments. This paper proposes a new framework, the LVRL (Lightweight Virtual Reality Libraries), which allows both creation and conversion of existing applications to VR without changing the structure of the application. The LVRL main objective is to provide a minimalist programming interface and non intrusive allowing the development of VR applications by non VR developers. This article describes the architecture of LVRL, its features, usage and the benefits obtained by the applications that use it.

Augmented Reality Using Projective Invariant Patterns

This paper presents an algorithm for using projective invariant patterns in augmented reality applications. It is actually an adaptation of a previous algorithm for an optical tracking device, that works with infrared illumination and filtering. The present algorithm removes the necessity of working in a controlled environment, which would be inadequate for augmented reality applications. In order to compensate the excess of image noise caused by the absence of the infrared system, the proposed algorithm includes a fast binary decision tree in the process flow. We show that the algorithm achieves real time rates.

Projection Mapping for a Kinect-Projector System

Spatial augmented reality allows users to create a projected virtual environment on irregular surfaces. This demands an extensive knowledge in the Camera-Projector calibration area. This paper presents a framework developed to facilitate the use of data achieved from a calibration of a Kinect-Projector system in visualization applications. Additionally, different calibration techniques were evaluated in order to demonstrate the better approaches.

Study and Evaluation of Separability Techniques and Occlusion in Multitouch Surfaces

Multitouch interfaces allow interacting with a virtual object directly, similar to a real object. However, there are several issues to be resolved, such as the accuracy of the manipulation, the occlusion, the separability of the manipulation, etc. Multitouch interfaces allow multiple spatial transformations that can be performed on a virtual object with only a gesture. For example, an object can be rotated, translated and scaled with two fingers with a single gesture. However, some unwanted movements may occur accidentally. Separability techniques appear with the intent to prevent unwanted movements on multitouch surfaces. Occlusion is another problem that occurs in multitouch interfaces. Often the user’s hand hides the vision of the object with which he/she interacts; or the user’s action on interface hinders the movement when it clicks on a bottom that triggers action. This paper proposes two techniques of separability, aiming to reduce the problems that arise due to excessive freedom of manipulation in multi-touch interfaces, and evaluates the efficiency of these techniques. The techniques developed are not only applicable in simple virtual objects; they are also for WIMP (windows, icons, menus, pointer) objects, aiming to reduce occlusion. A series of tests was performed to evaluate precision, occlusion time for completion of task, and ease of use.