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Publications

Publications by Augusto Sousa

2012

Sketch express: A sketching interface for facial animation

Authors
Miranda, JC; Alvarez, X; Orvalho, J; Gutierrez, D; Augusto Sousa, AA; Orvalho, V;

Publication
COMPUTERS & GRAPHICS-UK

Abstract
One of the most challenging tasks for an animator is to quickly create convincing facial expressions. Finding an effective control interface to manipulate facial geometry has traditionally required experienced users (usually technical directors), who create and place the necessary animation controls. Here we present our sketching interface control system, designed to reduce the time and effort necessary to create facial animations. Inspired in the way artists draw, where simple strokes define the shape of an object, our approach allows the user to sketch such strokes either directly on the 3D mesh or on two different types of canvas: a 2D fixed canvas or more flexible 2.5D dynamic screen-aligned billboards. In all cases, the strokes do not control the geometry of the face, but the underlying animation rig instead, allowing direct manipulation of the rig elements. Additionally, we show how the strokes can be easily reused in different characters, allowing retargeting of poses on several models. We illustrate our interactive approach using varied facial models of different styles showing that first time users typically create appealing 3D poses and animations in just a few minutes. We also present in this article the results of a user study. We deploy our method in an application for an artistic purpose. Our system has also been used in a pioneer serious game context, where the goal was to teach people with Autism Spectrum Disorders (ASD) to recognize facial emotions, using real time synthesis and automatic facial expression analysis.

1995

On writing a router for message passing in a transputer network

Authors
Sousa, AA; Ferreira, FN;

Publication
COMPUTING SYSTEMS IN ENGINEERING

Abstract
In a distributed memory MIMD parallel machine, the efficient communication between processes/processors, through messages, is an important task to be handled by the programmer. Because the number of inter-processor connections is limited, the communication between any two processors is made by passing the messages through several other processors and then, a problem of messages routing appears. For dedicated systems, special architectures can be defined simplifying the problem but, if an environment constituting a basis for general applications development is desired, the problem is more serious due to the deadlock possibility. A general router, able to avoid the problem, becomes then a very important tool for software development in parallel architectures. We have been defining a development platform, based on a network of Transputers and written in OCCAM, for image synthesis applications. This paper reports our efforts in writing different versions of routers, based on two different strategies, and justifies the choice of an efficient one to integrate in the platform.

2000

Graphical control of autonomous, virtual vehicles

Authors
Leitao, JM; Sousa, AA; Ferreira, FN;

Publication
2000 IEEE 51ST VEHICULAR TECHNOLOGY CONFERENCE, PROCEEDINGS, VOLS 1-3

Abstract
This paper presents some of the developments we made with the goal of allowing a friendly control and simulation of a large number of autonomous agents based in behavior in interactive real-time systems. Our work has been specially oriented to the simulation and control of autonomous vehicles and pedestrians in the preparation of scenarios to driving simulation experiments in the DriS simulator. Because every element is intrinsically autonomous, only a few of them are usually addressed to implement the desired study event. Also, because our model is autonomous and controllable, we can use the same model in the implementation of both environment traffic and controlled vehicles. Our scripting language is based in Grafcet, a well known graphical language used in the specification and programming of industrial controllers. Our technique allows the imposition of both short time orders and long time goals to each autonomous element. Orders can be triggered reactively using sensors that monitor the state of virtual traffic and configurable timers that generate all the necessary Fixed and variable time events.

2005

State Of The Art In Computer Graphics In Ibero-American Countries - Introduction

Authors
Comba, J; Navazo, I; de Sousa, AA;

Publication
COMPUTERS & GRAPHICS-UK

Abstract

2008

A didactic application for creating new sights from multiple images using light fields

Authors
Faria, BM; de Sousa, AA; Reis, LP;

Publication
COMPUTATIONAL VISION AND MEDICAL IMAGING PROCESSING

Abstract
A Light Field is an imaged based rendering technique based on the eight dimensional Plenoptic Function, simplified to a four dimensional function. It describes the amount of light covering the space, from any point, in any arbitrary direction. It ignores variables like the time and wavelength and assumes that radiance is equal throughout a line in the free space and so it is more efficient than most of the other image based rendering techniques in the literature. Drawbacks appear in the quality of the visualization but may be reduced by the correct use of the technique regarding the desired application. This paper presents a didactic application of this type of imaged based rendering technique that uses multiple sights of a scene through different points of views. The application of light-fields to medical images is thought one of the main objectives of this work and so, a simple application of this image based rendering technique, to this type of images is presented in order to show the usefulness of the approach.

2010

A Facade Tracking System for Outdoor Augmented Reality

Authors
Martins, JF; Silva, JA; Augusto de Sousa, AA;

Publication
WSCG 2010: FULL PAPERS PROCEEDINGS

Abstract
We describe a real-time facade tracking system that uses, as setup information, only two images of a facade, captured on the moment. No more previous information is needed, such as a facade 3D model, dimensions or aspect ratio. Feature points and their local descriptors are extracted from that pair of images and used during the detection and tracking of the facade. Additionally, parallax and topological information is also used in order to increase the overall robustness of the tracking process. Experiments show that the system can detect and track a wide variety of facades, including those that are not entirely planar, partially occluded or have few distinguishable visual landmarks. The reliance on on-the-spot information, alone, makes this system useful for Outdoor Augmented Reality applications, in an Anywhere Augmentation urban context.

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