Hierarchical system and method for on-demand loading of data in a navigation system

• US 7,305,396 B2
• Filed: 12/31/2002
• Issued: 12/04/2007
• Est. Priority Date: 12/31/2002
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schmidt, Hauke, Lee, Aaron, Chen, Tuolin
• Primary Examiner(s): MAHMOUDI, HASSAN
• Application Number:
  US10/334,240
• Publication Number:
  US 20040139080A1
• Time in Patent Office: 1,799 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G01C 21/3638 including 3D objects and buildings three dimensional [3D] modelling, e.g. data description of 3D objects G06T17/00; geographic models G06T17/05
• CPC Class Codes: G06T 17/005 Tree description, e.g. octree, quadtree
• CPC Class Codes: G06T 17/05 Geographic models
• CPC Class Codes: G06T 19/003 Navigation within 3D models or images
• CPC Class Codes: G06T 2210/12 Bounding box
• CPC Class Codes: G06T 2210/36 Level of detail
• CPC Class Codes: Y10S 707/99942 Manipulating data structure, e.g. compression, compaction, compilation
• CPC Class Codes: Y10S 707/99943 Generating database or data structure, e.g. via user interface

Abstract

A system providing three-dimensional visual navigation for a mobile unit includes a location calculation unit for calculating an instantaneous position of the mobile unit, a viewpoint control unit for determining a viewing frustum from the instantaneous position, a scenegraph manager in communication with at least one geo-database to obtain geographic object data associated with the viewing frustum and generating a scenegraph organizing the geographic object data, and a scenegraph renderer which graphically renders the scenegraph in real time. To enhance depiction, a method for blending images of different resolutions in the scenegraph reduces abrupt changes as the mobile unit moves relative to the depicted geographic objects. Data structures for storage and run-time access of information regarding the geographic object data permit on-demand loading of the data based on the viewing frustum and allow the navigational system to dynamically load, on-demand, only those objects that are visible to the user.

Claims

1. A method for accessing identification information of a tile associated with a viewing frustum comprising:

organizing tile identification information hierarchically according to an RIF data structure format;

submitting queries for tile identification information, the queries including a location parameter associated with the viewing frustum;

searching through the RIF data structure to find tile identification information matching the location parameter; and

accessing discovered tile identification information,

wherein;

the RIF data structure includes a file location field, a bounding box field, a tiles field, and a number of children field; and

the number of children field is recursive, each child including a further bounding box field, a further tiles field and a further number of children field.

2. A method for accessing image data of a tile associated with a viewing frustum, the tile image data including a first image having a first resolution and a second image having a second resolution, the method comprising:

organizing tile identification information hierarchically according to an RIF data structure format;

obtaining tile identification information using a location parameter associated with the viewing frustum;

using the tile identification information as an index to a LOD file, the LOD file indicating a storage location of the tile image data;

assigning first and second blending factors for the first and second resolutions of the tile image data;

computing a weighted sum of the first image and the second image multiplied by their respective first and second blending factors; and

generating a multiresolution image based on the weighted sum of the first and second images.