Post on 02-Feb-2016
description
iMAGIS-GRAVIR / IMAG
Augmented Reality Collaborative Environment:
Calibration and Interactive Scene Editing
Raphaël GrassetXavier DecoretJean-Dominique Gascuel
iMAGIS-GRAVIR/IMAG
iMAGIS is a joint project between CNRS,INRIA,INPG and UJF
iMAGIS-GRAVIR / IMAG
Motivations
Focus on: – tracking and registration of virtual and real objects.– commercial age: off the shelf and personal hardware.
Purpose: propose a collaborative environment for multi-user in augmented reality.
iMAGIS-GRAVIR / IMAG
Related Works
Some Augmented Reality Environments
•GRASP[1995]
•Studierstube[1998]
•EMMIE[1999]
iMAGIS-GRAVIR / IMAG
Overview•Motivation and Related Works
•Setup: Small Group and Computing Environment
•Calibration Procedure– HMD Calibration– Pen Calibration– World Calibration
•Dynamic Objects– Mixing Real and Virtual objects– Moving Objects
•Conclusion
iMAGIS-GRAVIR / IMAG
Setup: Small GroupCentralized Configuration:
– user around a table: face to face collaboration.– personal and shared area.
Shared area
Personal area(virtual menu, private data)
iMAGIS-GRAVIR / IMAG
Setup: Computing Environment
•Visualization: optical see-through HMDdirect view, private information, low weight.
•Interaction: stylus
easy use.
•Tracking: magnetic tracker
fast, no line of sight.
iMAGIS-GRAVIR / IMAG
Overview•Motivation and Related Works
•Setup: Small Group and Computing Environment
•Calibration Procedure– HMD Calibration– Pen Calibration– World Calibration
•Dynamic Objects– Mixing Real and Virtual objects– Moving Objects
•Conclusion
iMAGIS-GRAVIR / IMAG
Calibration Procedure
World CS
Image CS
Transmitter CS
Receptor CS
Emitter CS
Eye CSHMD CS
Tip CS
Purpose: obtain the relations between different coordinate systems (CS).
HMD CS = middle between the 2 optic centers of the HMD.
Style: fast and accurate interactive procedure.
iMAGIS-GRAVIR / IMAG
Calibration Procedure
World CS
Image CS
Transmitter CS
Receptor CS
Emitter CS
Eye CSHMD CS
Tip CSHMD CS = middle between the 2 optic centers of the HMD.
Style: fast and accurate interactive procedure.
HMD Calibration
Purpose: obtain the relations between different coordinate systems (CS).
iMAGIS-GRAVIR / IMAG
Calibration Procedure
World CS
Image CS
Transmitter CS
Receptor CS
Emitter CS
Eye CSHMD CS
Tip CSHMD CS = middle between the 2 optic centers of the HMD.
Style: fast and accurate interactive procedure.
Pen Calibration
Purpose: obtain the relations between different coordinate systems (CS).
iMAGIS-GRAVIR / IMAG
Calibration Procedure
World CS
Image CS
Transmitter CS
Receptor CS
Emitter CS
Eye CSHMD CS
Tip CSHMD CS = middle between the 2 optic centers of the HMD.
Style: fast and accurate interactive procedure.World Calibration
Purpose: obtain the relations between different coordinate systems (CS).
iMAGIS-GRAVIR / IMAG
Related Works
Some Calibration Methods:
•Azuma[1994] & Oishi[1996]: lot of hardware.
•Tuceryan[1995]: video see-through method
iMAGIS-GRAVIR / IMAG
Related Works
•Fuhrmann[1999] (Studierstube): calibration with a tracked pen.
•Genc[2000] (GRASP): vision approach.
iMAGIS-GRAVIR / IMAG
HMD CalibrationPurpose: transformation between the Receptor CS and the Image CS.Style: reduce user effort.
Constraints: personnal hardware => removable tracker on the HMD.
Depends on the position of the tracker in the HMD (HMD CS Receptor CS), Morphology ..etc..
iMAGIS-GRAVIR / IMAG
HMD Calibration: Procedure
Receptor CS
HMD CS
Eye CS
Emitter CS
Misalignment
Method: freeze the view and align a virtual object with real object.
Virtual Emitter
1.Freeze the view
iMAGIS-GRAVIR / IMAG
HMD Calibration: Procedure
Receptor CS
HMD CS
Eye CS
Emitter CS
Virtual Emitter
Freeze View
2. Move head
Method: freeze the view and align a virtual object with real object.
iMAGIS-GRAVIR / IMAG
HMD Calibration: Procedure
Receptor CS
HMD CS
Eye CS
Emitter CS
Virtual Emitter
Freeze View
3. Unfreeze the view
Method: freeze the view and align a virtual object with real object.
iMAGIS-GRAVIR / IMAG
HMD Calibration: Procedure
Receptor CS
HMD CS
Eye CS
Emitter CS
Virtual Emitter
Incremental realignment.
4. Compute transformation
Method: freeze the view and align a virtual object with real object.
iMAGIS-GRAVIR / IMAG
Pen Calibration: Principles and Procedures
Purpose: transformation between the Transmitter CS and the Tip CS.
Method: orient the stylus in n representative directions.
Emitter CS
Fixed tip
Compute by SVD (nx3 equations, 6 unknowns).
iMAGIS-GRAVIR / IMAG
Pen Calibration: Results
SVD on 100x3 equations SVD on 4x3 equations
Tracker positions
Reconstruction of the tip
We propose to keep just 4 measurements.
iMAGIS-GRAVIR / IMAG
World CalibrationPurpose: transformation between the Emitter CS and the World CS.
Method: selection of 4 corners of shared area.
P1
P2P3
P4
Emitter CSWorld CS
iMAGIS-GRAVIR / IMAG
Calibration Results
Error largely acceptable for most practical applications.
2 cm
Different views of the source square with a virtual figure added: no disturbing drift.
iMAGIS-GRAVIR / IMAG
Overview•Motivation and Related Works
•Setup: Small Group and Computing Environment
•Calibration Procedure– HMD Calibration– Pen Calibration– World Calibration
•Dynamic Objects– Mixing Real and Virtual objects– Moving Objects
•Conclusion
iMAGIS-GRAVIR / IMAG
Dynamics objects: Mixing Real and Virtual Environment
Purpose: – Describe real objects to the system.– Tangible User Interface.– Poor man haptic feedback.
Requirements:– Occlusion compatibility (« black render »).– Respect of laws of physics (e.g gravity). – Manipulation awareness.
Our approach: interactive system easy use based on visual feedback.
• Digitalized objects.• Generic Geometric models.• TUI objects.
iMAGIS-GRAVIR / IMAG
Related WorksSome interactions with real objects
•Whitaker[1995]: image-based and pointer-based object calibration.
•Mixed Reality[1999]: features on objects.
•Build-IT[1997]
iMAGIS-GRAVIR / IMAG
Mixing with Already Digitalized Models (1/2)
Purpose: obtain transformation between the object CS and the world CS (known geometry + appearance).
Constraints: laying on top of something else (3DOF).Method: superpose virtual representation with real representation of the model.
Real object Virtual objectObject CS
iMAGIS-GRAVIR / IMAG
Mixing with New Simple ModelsPurpose: obtain the geometry and the position of generic objects (cube, cylinder, cone, ..etc..)
Our approach: Description of simple shapes with few points.
Example: add a rectangle.
8 DOF
iMAGIS-GRAVIR / IMAG
Mixing with New Simple Models
P1
5 DOF
Purpose: obtain the geometry and the position of generic objects (cube, cylinder, cone, ..etc..)
Our approach: Description of simple shape with few points.
Example: add a rectangle.
iMAGIS-GRAVIR / IMAG
Mixing with New Simple Models
P1
5 DOF
Purpose: obtain the geometry and the position of generic objects (cube, cylinder, cone, ..etc..)
Our approach: Description of simple shape with few points.
Example: add a rectangle.
iMAGIS-GRAVIR / IMAG
Mixing with New Simple Models
P1
2 DOF
P2
Purpose: obtain the geometry and the position of generic objects (cube, cylinder, cone, ..etc..)
Our approach: Description of simple shape with few points.
Example: add a rectangle.
iMAGIS-GRAVIR / IMAG
Mixing with New Simple Models
P1
0 DOF
P2
Purpose: obtain the geometry and the position of generic objects (cube, cylinder, cone, ..etc..)
Our approach: Description of simple shape with few points.
Example: add a rectangle.
iMAGIS-GRAVIR / IMAG
Mixing with New Simple Models: Results
iMAGIS-GRAVIR / IMAG
Tangible User Interface:Moving Objects
Purpose: use real object for manipulation of virtual models.Constraints: one tracker + several real objects to manipulate.
Our approach: TEMPORARILY stick the magnetic tracker to previously added objects.
Real object
iMAGIS-GRAVIR / IMAG
Video
iMAGIS-GRAVIR / IMAG
ConclusionOur contributions• Multi-user environment setup.• Fast user calibration method with sufficient accuracy
for a large range of non-critical applications.• Dynamic placement and digitalization of objects.• Intuitive metaphor to manipulate objects.
Future works• Develop interaction techniques.• Reduce latency.
iMAGIS-GRAVIR / IMAG
iMAGIS-GRAVIR / IMAG
Mixing with already Digitalized Models (2/2)
Real object