Ferret:RFID Localization for Pervasive
Multimedia
Xiaotao Liu,Mark D.Corner,and Prashant Shenoy
Department of Computer Science
University of Massachusetts,Amherst,MA
{xiaotaol,mcorner,shenoy}@
Abstract.The pervasive nature of multimedia recording devices en-
ables novel pervasive multimedia applications with automatic,inexpen-
sive,and ubiquitous identification and locationing abilities.We present
the design and implementation of Ferret,a scalable system for locating
nomadic objects augmented with RFID tags and displaying them to a
user in real-time.We present two alternative algorithms for refining a
postulation of an object’s location using a stream of noisy readings from
an RFID reader:an online algorithm for real-time use on a mobile device,
and an offline algorithm for use in post-processing applications.We also
present methods for detecting when nomadic objects move and how to
reset the algorithms to restart the refinement process.An experimental
evaluation of the Ferret prototype shows that(i)Ferret can refine object
locations to only1%of the reader’s coverage region in less than2min-
utes with small error rate(2.22%);(ii)Ferret can detect nomadic objects
with100%accuracy when the nomadic distances exceed20cm;and(iii)
Ferret works with a variety of user mobility patterns.
1Introduction
Advances in digital imaging technologies have led to a proliferation of consumer devices with video capture capabilities.The pervasive nature of multimedia recording devices such as cellphones,digital camcorders,PDAs and laptops, has made it relatively simple to capture,transform,and share large volumes of personal video and image content.A concurrent trend is the emergence of low-cost identification technologies such as RFID tags,designed to replace bar-codes[12].Each tag contains a numeric code that uniquely identifies the object and can be queried by a wireless reader.It is likely that in the near future many personal objects(e.g.,books,clothing,food items,furniture)will be equipped with self-identifying RFID tags.
The confluence of these trends—the ubiquity of RFID tags and the perva-sive nature of multimedia recording devices—enables novel pervasive multimedia applications with automatic,inexpensive,and ubiquitous identification and lo-cation abilities.By equipping cameras with RFID readers,it is possible to record This research was supported in part by NSF grants National Science Foundation grants CNS-0219520,CNS-052072and EIA-0098060.
