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RFIG combines RFID and geometry to provide precise location data and facilitate complex geometric procedures using photosensing wireless tags and a handheld projector. This technology offers enhanced functionality, high-accuracy location determination, and selective communication with tags.
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R F I G : RFID + GeometryPhotosensing Wireless Tags for Precise Location and Complex Geometric Procedures Ramesh Raskar, Paul Dietz, Paul Beardsley, Darren Leigh,Jeroen van Baar
Problem Example: 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 ?) The solution: RFIG
What is RFIG?RFIG = RF Id + Geometry • RFIG is a system for finding location of (photosensitive) RF tags using a hand-held projector Photosensing Wireless Tags LED Projector Interactive stabilized projection
Visual Feedback of location with Photosensing RFID + Pocket ProjectorMovie
Mitsubishi Electric Pocket Projector DLP based with R, G, B LEDs Instant on, battery-pack Available Now
From RFID to RFIG Conventional RFID Photosensing RFID Tag RFIG System
RFIG Operation Procedure Steps • RF reader initializes system; projector produces a sequence of aiming patterns • Temporal signal at each tag photodiode is decoded at the tag, and this uniquely defines its position • Tag transmits via RF its ID#, its coordinates (and other information, as required by the application) • Reading system processes the information and determines the designating pattern that the projector has to produce in order to help the user accomplish the task
t = 0 t = T t = 2T t = 3T t = 4T Step 1: Project Sequential Aiming PatternsStep 2: Tag Decodes its Position Sequence example for determining x - coordinate Tag photodiode Total projected area x = 1 0 1 0 0 = 20
Example: Complete Set of 5-bit 2D Aiming Patterns x y N = # of illumination patterns per axis (= # of bits) For example: N=10, Illuminated area size = 10 m ==> Spatial resolution = 1 cm
Step 3: Tag Transmits ID & {x,y} CoordinatesStep 4: Projector Provides User Feedback Example: • Project green spots on items that have to be moved to store front • Project red spots on items that need to be returned to supplier
First Experimental Set-Up Tag Modified Projector
Advantages and Limitations • Advantages • Enhanced functionality • High-accuracy location determination • Ability to communicate with tags selectively • RF collision avoidance • Minimal impact on tag in terms of • Cost • Size • Power consumption • Limiting requirements • Line of sight • Modified packaging
Alternative RF+Optical Approaches Yoshikawa RF Systems (125 kHz) PHOCI (Cliffton Labs)Blinking LEDs + Special Camera LED / CCD RFIG long Range LED / RFID short yes no Battery
RFIG Application Example: Surveillance Detect Arrangement ChangeWithout Fixed Camera and In Any Lighting Condition Before After Record coordinates of tags from one view Compare with new coordinates from a different view
Application Example: 3D from 2 Projector Views(Structure from Motion) • Two+ unknown projector views • Correspondence is trivial • Applications • Detect 3D deformations • Asset tracking facilitation • Trajectory grouping
Application Examples • Location tracking • Hospitals, locating medicines • Asset tracking, warehouses • Factory automation, • Sorting, routing, directing packaging • Positioning products on assembly line • Entertainment, games, motion capture • Occlusion detection • Railway tracks • Occupancy in public areas • Change detection • Surveillance, Monitoring buildings and bridges structures • Augmented reality • Visual feedback in control rooms, HCI
The iGlassware System • The prototype instrumented glass
R F I G R F I D (Radio Frequency Id & Geometry) Photosensing Wireless Tags Find tag location usinghandheld Projector Simultaneous readers without RF Collision Many geometric ops Google search term: RFIG