Development of New User Interface for 3D GIS using Mobile Terminal
Akira Takuma, Ryosuke Shibasaki and Minoru Fujii
Institute of Industrial Science, University of Tokyo
7-22-1, Roppongi, Minato-ku, Tokyo, 106 Japan
Tel: ++81-3-3402-6231 Fax L ++81-3-3408-8268
E-mail :takuma@shunji.iis.u.-tokyo.ac.jp
Abstract
The authors developed a new user interface for 3D GIS, which allow users to retrieve necessarily information from the database easily by only clicking "REAL" objects in live video image. At first we developed the "Fixed-position" system using a video camera, a workstation with 3D graphic library and 3D GIS database to check the relevance of our idea. Then, we are evolving to the development of a "Mobile" system using mobile terminal. This terminal consists of a personal computer, a CCD video camera with Differential GPS (to obtain location data) and Fiber Optical Gyroscope (to obtain angle data) and 3D GIS database. In the future, this system will be useful for "personal navigation" system, disaster investigation, updating GIS database, daily inspection of infrastructures, information guide system and so forth.
Introduction
This research proposes a new user interface for 3-Dimensional GIS which enable us to retrieve information of an object in "Real World" (Not in Cyber World) only by pointing it through a live video image. This concept is an application of "Augmented Reality (AR)" which is now widely noticed in computer vision society. AR enables "fusing" contents of a database with the "Real World" by embedding objects in the spatial database into a live video image. In this sense, AR is closer to human sense than Virtual Reality.
Based on the development of a "Fixed-position" system to validate the relevance of the concept of this user interface (See the Reference 2). Development of a "Mobile" system is now being conducted. These are systems which allow a user to click an object in a real image on the computer display to retrieve the information (attribute data) of the object (See [Fig-1]).
[Fig-1] The result of using "Fixed-position" system
(Name, address, direction and distance form the viewpoint is shown
in Japanese character.)
These systems have the underlying processes as follows:
- Capture a real image form a user's viewpoint through a video camera.
- Create a CG image of a view at the same place from the 3D spatial data, so that the CG image can be exactly overlaid to the video image. Exact overlay of the video image with the CG can be achieved by using location data and view angle data of the vide camera.
- With the exact overlay, each object in the video image is linked with the corresponding object in CG image.
- The user can point an object (e.g. building) in the video image by a mouse pointer to retrieve information of the corresponding object in the CG image.
Using these systems, users need not make any efforts to establish the relationships between an object in real image and one is 2D map, and they can retrieve the necessary information in a natural manner at any moment from a live image they see. As a result, the applicability or potential of 3D GIS will be much enhanced. We can use these systems for personal navigation and information guidance system, of course, and investigation after disaster, simulation of landscape, daily inspection of above-ground and underground structures, updating of GIS Database, and so forth. In addition, one can see" Invisible" objects in the GIS database at the site.
In this paper, we will report the result of development of "Fixed-position" system, the process of development of "Mobile" system, and the improvement plan for the future.
Development of "Fixed-position" system
As the first step, the authors developed a "Fixed-position System". The structure of this system is shown in [Fig-2]. It is composed of a workstation, with graphics library and GIS database (3D location data of building in some part of Tokyo area), and a video theodolite (fixed at a certain position) for capturing real video images.
[Fig-2] Structure of "Fixed-position" system
The functions of this systems are as follows;
- The video image and the CG images are overlaid almost exactly using the position and viewing angle of the video theodolite. Users can retrieve the information (name, address and distance from the video position) of the building pointed by clicking the "REAL" building on the display, (see [Fig-3])
- In addition a building users are searching for can be shown (zoomed in by a video camera) on the display by inputting the name. An example output of this system is already shown in [Fig-1].
The problems lefts of this system were as follows:
- The video camera is fixed at a specific location and the applicability is limited.
- Generation of CG image takes relatively long time, due to the large size of 3D data.
- The elevation data in the database has only limited accuracy, and the overlaying can not be so exact.
To solve these problems, we started to develop "Mobile" system.
