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R F I G Lamps : Interacting with a Self-describing World via Photosensing Wireless Tags and Projectors. Ramesh Raskar, Paul Beardsley, Jeroen van Baar, Yao Wang, Paul Dietz, Johnny Lee, Darren Leigh, Thomas Willwacher Mitsubishi Electric Research Labs (MERL), Cambridge, MA.
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R F I G Lamps : Interacting with a Self-describing World via Photosensing Wireless Tags and Projectors Ramesh Raskar, Paul Beardsley, Jeroen van Baar, Yao Wang, Paul Dietz, Johnny Lee, Darren Leigh, Thomas Willwacher Mitsubishi Electric Research Labs (MERL), Cambridge, MA
Radio Frequency Identification Tags (RFID) No batteries, Small size, Cost few cents Antenna microchip
Warehousing Routing Livestock tracking Library Baggage handling Currency
Tagged Books in a Library • Id List of books in RF range • No Precise Location Data Are books in sorted order ? Which book is upside down ?
Conventional RF tag Photo-sensing RF tag
Photosensor ? Compatible with RFID size and power needs Projector ? Directional transfer,AR with Image overlay
b. Tags respond with date and precise (x,y) pixel location, Projector beams ‘Ok’ at that location a. Photosensing RFID tagsare queried via RF c. Multiple users can simultaneously work from a distance without RF collision
RFID(Radio Frequency Identification) RFIG(Radio Frequency Id and Geometry)
Prototype Tag RF tag + photosensor
Outline • Photosensing RF tags • Location sensing • Geometric Operations • Multi-view analysis • Deformation • Interactive Projection • Mouse-like interaction • Image stabilization
Outline • Photosensing RF tags • Location sensing • Geometric Operations • Multi-view analysis • Deformation • Interactive Projection • Mouse-like interaction • Image stabilization • Applications
Projected Sequential Frames PatternMSB PatternMSB-1 PatternLSB • Handheld Projector beams binary coded stripes • Tags decode temporal code
Projected Sequential Frames PatternMSB PatternMSB-1 PatternLSB • Handheld Projector beams binary coded stripes • Tags decode temporal code
Projected Sequential Frames PatternMSB PatternMSB-1 PatternLSB • Handheld Projector beams binary coded stripes • Tags decode temporal code
Projected Sequential Frames PatternMSB PatternMSB-1 PatternLSB • Handheld Projector beams binary coded stripes • Tags decode temporal code
Projected Sequential Frames PatternMSB PatternMSB-1 PatternLSB • Handheld Projector beams binary coded stripes • Tags decode temporal code
PatternMSB PatternMSB-1 PatternLSB 0 1 1 0 0 X=12 • For each tag • From light sequence, decode x and ycoordinate • Transmit back to RF reader (Id, x, y)
Visual feedback of 2D position • Receive via RF {(x1,y1), (x2,y2), …} pixels • Illuminate those positions
Limitations • Line of sight • Surface patches • Multiple tags per object • Ambient light • Modulated infrared • Surface reflectance and shadows
Outline • Photosensing RF tags • Location sensing • Geometric Operations • Multi-view analysis • Deformation • Interactive Projection • Mouse-like interaction • Image stabilization • Applications
Find 3D coordinates • Observe structured patterns via Camera • Triangulate cam/proj view
3D from 2 Projector Views(Structure from Motion) • Two+ unknown projector views • Correspondence is trivial • Applications • Detect 3D deformations • Trajectory grouping
Change Detection without fixed camera, in any lighting condition Before After Record coordinates of tags from one view Compare with new coordinates from a different view
Outline • Photosensing RF tags • Location sensing • Geometric Operations • Multi-view analysis • Deformation • Interactive Projection • Desktop-like interaction • Image stabilization • Applications
Desktop-like Interaction Selecting tags
Mouse Simulation • Cursor follows handheld projector motion • Pre-warped image remains stable
Image Quasi-Stabilization Eliminate hand jitter using inertial sensors+camera
Absolute Stabilization Image stays registered with world features
Interactive Projection (Also in Emerging Technologies Booth)
Adaptive Projection ‘Paste’ : Geometric and Photometric compensation
Related Work • Smart objects • Smart-its • FindIT Flashlight (Ma and Paradiso 2002) • Location sensing • Multiple readers, large antennas • Olivetti Active Badge, Xerox PARCtab (Want 1995) • Interaction and Display • Augmented Reality • Projector-based AR, Shaderlamps (Raskar 1998, Underkoffler 1999, Pinhanez 2001) • Handheld projector (Raskar 2003)
Applications • Single Tags • Authoring for AR, Store augmentation: display per object • Multiple tags on objects • 3D Pose • Packing and placement strategy • Robot navigation • Interaction between tagged objects • History of geometric interaction • Orientation mismatch • Distributed tags • Deformation • Interpolated values for temperature sensors
Acknowledgements • MERL • Cliff Forlines • Joe Marks, • Dick Waters, Kent Wittenburg • Vlad Branzoi • Rebecca Xiong, Debbi van Baar • Mitsubishi Electric, Japan • Mamuro Kato, • Keiichi Shiotani
Interacting with a Self-Describing World • Hybrid optical and RF communication • Photosensing Wireless Tags + Projector illumination • Geometric Analysis • Location, Selection, Augmentation At a distance • Interactive Projection • Desktop like interaction • Stabilized images • RFIG Applications beyond logistics • Identity, Geometry, History, Annotation www.MERL.com
G R F I R F I D (Radio Frequency Id & Geometry) Photosensing Wireless Tags Find tag location usinghandheld Projector Interactive stabilized projection Many geometric ops
Towards Passive RFID • Photosensor • Most compatible with passive batteryless RFID • Power: near zero power for sensing • Size: Each photocell is tens of micrometer (smaller than RFID which are about 500 micrometer) • Very low cost, can be built with silicon of RFID microchip • RFID+Photosensor can be size of grain of rice • RFIG tag is ‘visible’ to projector but not to humans • Current prototype uses battery because passive tags are difficult to program • Other possibilities • Adding a light emitting diode (LED) • Requires on board power • Size has to be considerably large • Size and power requirements are high
Future Directions • Sophisticated tags • Light modulation • Handheld projector
Comparison with Bar-codes • RFID • Barcodes take up more space • Long bit sequences • Multiple tags can be simultaneously read • Read distance is high • RFIG • Multiple barcodes per object is cumbersome • Difficult to attach sensor (e.g. temperature)
Locate Tags Precisely using a handheld scanner/projector Illuminate tags with binary coded stripes with projector • Handheld device • Eliminates multiple RF readers for triangulation or large antennas • Projector indicates location of tag
Photosensor added to RFID tags • Hybrid communication via RF and via light • Solve 3 main issues with conventional RFIDs • Locate tags precisely • Select a subset of tags for operation • Long distance operation without collision • Applications beyond inventory management • Warehouse: locate objects for specific queries • Training and maintenance: interactive augmented reality • Surveillance: keep trail of object locations
2. Select subset of tags for operation 3. Long distance operation without RF collision • Technique • Illuminate subset of tags with flashlight or projector • Advantages • Only tags which are illuminated respond to queries • No RF collision between multiple tags • Projector also use as a display to indicate result of operation
Interactive Projection • Desktop like interaction • Cursor follows use motion • Center pixel is the pointer • Rest of the image is stabilized • Selection • Image stabilization • Absolute: camera and inertial sensor • Relative: world markers • Copy-paste • Camera captures texture during ‘copy’ • Projection after geometric/photometric adaptation