Celso Setsuo Kurashima

A technical analysis of digital television broadcasting in brazil

The digitalization of terrestrial television broadcasting systems has been carried out in many countries around the world. Replacing the previous analogue video signal by the high-definition digital video has provided several technical benefits to the population, and nowadays it is an irreversible change. In Brazil, this process began in 2007, when the first terrestrial broadcasting of digital television was launched in Sao Paulo City. The Brazilian Digital Television system is referred as to ISDB-T B, because it is mostly based on the system called ISDB-T, which was originally developed in Japan. This paper presents a technical overview of this system in Brazil, and also reports its current status from a technical point of view regarding transmission features. Measurements of several transmission parameters are presented and followed by an analysis of the system situation in Brazil.

FastFusion: A Scalable Multi-projector System

Multi-projector systems offer both higher resolution and brightness by using a cluster of projectors, and it can provide better visual quality when compared to traditional systems using a single high performance projector. When we consider the high cost associated with high-end projectors, the use of multiple low cost projectors can reduce considerably the cost of such installation. This article presents the research and development of a scalable multi-projection system that enables the construction of virtual reality systems with a large number of projectors and graphics computers, and that is capable of achieving a high resolution display. We demonstrate the viability of such system with the development of a camera-based multi-projector system called FastFusion, which automatically calibrates casually aligned projectors to properly blend different projections. Our system software improves known algorithms in the literature for projector calibration and image blending. The main improvement is a more efficient distribution of the calibration process. In addition, since our library proposes a new architecture that is able to manage many projectors, it may lead to the development of Immersion Systems with retina resolution. FastFusion has been tested and validated by virtual reality applications. In this work, we analyze the visual performance of FastFusion in a CAVE system with three walls, eighteen projectors and nine computers.

Crosscale: A 3D virtual musical instrument interface

Inspired by principles for designing musical instruments we implemented a new 3D virtual instrument with a particular mapping of touchable virtual spheres to notes and chords of a given musical scale. The objects are metaphors for note keys organized in multiple lines, forming a playable spatial instrument where the player can perform certain sequences of notes and chords across the scale employing short gestures that minimizes jump distances. The idea of different arrangements for notes over the playable space is not new, being pursued on alternative keyboards for instance. This implementation employed an Oculus Rift and a Razer Hydra for gesture input and showed that customization of instrumental mappings using 3D tools can contribute to ease the performance of complex songs by allowing fast execution of specific note combinations.

Analysis of stereoscopic 3DTV broadcasting for ISDB-TB system

This paper presents an analysis of stereoscopic 3DTV broadcasting in ISDB-T International system, which is a terrestrial television system used in Brazil. Although 3DTV sets are well deployed, the 3DTV broadcasting services are not regulated in this market yet. We present results of a Side-by-Side 3D video broadcasting analysis with objective video quality parameters.

Results of DTV broadcasting parameters field measurement for multimedia transmission analysis

In digital television systems, measurements of transmission parameters are important basis for services expansion an planning. This paper presents results of field measurements of DTV broadcasting parameters for multimedia transmission analysis of the ISDB-TB system. The measurements were carried out in a Brazilian city, and allow the analysis of main broadcasting features used in DTV channels. Broadcasting parameters and video plus audio stream bitrate are analyzed. These results target future services planning.

A Small-Scale and Flexible Platform for Multi-projector Systems Development

Multi-projector systems for VR applications require complex infrastructure composed of several projectors and computers. Management of this complex structure is a challenge and requires expert personnel to keep it operational. In this paper we propose a flexible, mobile, off-the-shelf computing platform, targeted at the development of multi-projector displays algorithms. The goal is to achieve a fast development and debugging environment with low cost and system flexibility. Our approach consists of using pico projectors, that uses DLP technology for high efficiency projection, so that they are assembled in a much smaller size than off-the-shelf multimedia projectors. A grid array of several pico-projectors can be arranged within a small compact structure. Our small-scale platform includes only a laptop computer and an array of projectors, such that it may be easily transported to and mounted anywhere. When comparing to a full-scale multi- projector environment, this platform has several advantages, from a developers point of view, such as speedup testing and analysis of applications because of faster overall feedback to compile, run and make visual analysis. We have achieved not only a low cost development environment but also a flexible system, which features faster debugging and small setup time. In our experiments, we have successfully used this platform to develop and validate a geometric and color calibration library for our multi-projector systems called Fast Fusion.

Portable-Spheree: A portable 3D perspective-corrected interactive spherical scalable display

In this poster we present Portable-Spheree, an interactive spherical rear-projected 3D-content-display that provides perspective-corrected views according to the users head position, to provide parallax, shading and occlusion depth cues. Portable-Spheree is an evolution of the Spheree and it is developed in a smaller form factor, using more projectors and a dark-translucent screen with increased contrast. We present some preliminary results of this new configuration as well as applications with spatial interaction that might benefit from this new form factor.

Batmen — Hybrid collaborative object manipulation using mobile devices

In this work we present an interactive and collaborative 3D object manipulation system using the shelf mobile devices coupled with Augmented Reality (AR) technology that allows multiple users to collaborate concurrently on a scene. Each user interested in participating in this collaboration uses both a mobile device running android and a desktop (or laptop) working in tandem. The 3D scene was visualized by the user in the desktop system. The changes in the scene viewpoint changes and the object manipulations were performed using a mobile device through the AR. The system leverages users knowledge of common tasks performed on current mobile devices such as pinching for zooming in and out; swiping with one or two fingers for object rotation and press-and-hold for 2 seconds for object translation. As you will see in this video, we built a prototype system (in a maze style) and applied an informal user study with three experienced VR researchers. Users had to carry a 3D cube through three square rings along the maze. In resume, we diagnosed that working in a collaborative way (users A and B) was better and easier than individual one (user C). We registered more than 2 minutes late for the individual experience comparing to the teamwork. It may happen because the two player team shared information, functions and had a multi-perspective view during the task.