Section: New Results

Mixed Reality Environment

The concept of Mixed Reality comes from the fact that the real-virtual dichotomy is not sharp. Augmented Reality (AR) mode refers to all cases in which the auditory or visual display of a real environment is augmented by virtual sound or graphic objects. Pedestrian navigation is one of the numerous applications that fit into this field. Depending on the real speed of the user and on the real environment in which he moves (inside a building, ...), the system is augmented with synthetic audio instructions and points of interest. OpenStreetMap format has been extended to support navigation authoring and information related to the various passive or active location providers supported by IXE such as PDR, GPS and NFC.

Navigation Authoring

We defined a cue-based XML language (A2ML, for Advanced Audio Markup Language) using SMIL for internal and external synchronization of sound objects. A2ML is specified by a RELAX-NG grammar. A rule-based selector mechanism allows defining style sheets for OpenStreetMap (OSM) elements. This auditory display together with TTS makes our IXE browser accessible to visually impaired people. Format and Delivery for Mixed Reality Content IXE is based on an extended OSM data format with triggering zones, relations or groups with specific semantics and nodes or POIs whose URIs refer to content expressed in HTML5 and A2ML. Content delivery can be of two types, push or pull. Push content is coming from POIs which trigger when the user enters a new zone. This kind of content is very useful for navigation. We support it through a triggering specification that is inserted in the OpenStreetMap document. We use style sheets with rules to specify both the audio and visual rendering of the various types of OSM nodes. Pull content allows users to search detailed information about the artifacts that are located in the content referenced by the POI. Most of the time, this content is described using HTML5 and A2ML.

Location Provider Fusion

Pedestrian navigation can be done with several sensors. GPS locations are better for outside locations, PDR is useful to guide people indoor, but we can also use NFC tags, user proprioception, wifi... Our researches focus on a smart fusion of providers depending on sensor accuracy and on the context in which the person moves. We start by using Kalman Filter to smooth locations and disable jumps during the walk. These algorithms have been successfully tested during Venturi Y2 demo.

Map Rendering

We worked on offline map rendering around two solutions. The first one is based on an open source Android project called Mapsforge ; it provides a tile generation mechanism from a given OpenStreetMap file and a tile caching system for fast rendering on mobile devices. We mainly enhanced the open source project by increasing the zoom level limitation (21 by default) to 24 for displaying indoor maps. The other solution on which we worked is SVG-oriented and based on OpenLayers (dedicated to web browsers). As the rendering uses SVG we are no longer limited by a maximum zoom level. On the other hand, the SVG drawing has to be fully designed by the author, as we don't support, for the time being, SVG file generation from an OpenStreetMap document. These two approaches are different and their uses depend on the desired level of customization of the rendering (generated automatically or manually).