Joshua R. Smith, Ph.D.

Principal Investigator Sensor Systems Laboratory
Milton and Delia Zeutschel Professor
Allen School of Computer Science and Engineering, University of Washington
Department of Electrical and Computer Engineering, University of Washington

Research Overview

Looking for information on the WISP project? These links may be helpful: Overview page on this site and WISP Wiki and WISP 5 Wiki

Professor Smith's research aims to improve the connection of information systems to the physical world. The research has application in areas such as ubiquitous computing, robotics, wireless power, and medical devices. One theme explored in his research is alternative sensing systems not modeled on human perceptual systems.


Ph.D. 1999, M.S. 1995, Massachusetts Institute of Technology. Advisor: Neil Gershenfeld. Dissertation: Electric Field Imaging.

M.A. 1997 (B.A. Hons 1993), University of Cambridge. Natural Sciences (Physics and Theoretical Physics).

B.A. 1991 Magna Cum Laude, Williams College. Computer Science, Philosophy. Highest Honors for Thesis.

Extended Biography
University of Washington
Joshua R. Smith is the Milton and Delia Zeutschel Professor, jointly appointed in the Allen School of Computer Science, and in the Department of Electrical and Computer Engineering at the University of Washington, wher he leads Sensor Systems Laboratory. His research focusses on inventing new sensor systems, devising new ways to power and communicate with them, and developing algorithms for using them. This research has applications in the domains of ubiquitous computing, robotics, medical devices and HCI. His group works develops novel sensors for robotic manipulation, resonant wireless power transfer, and far-field wirelessly powered sensing platforms.

Intel Research Seattle
Formerly, he was a Principal Engineer at Intel Research Seattle, where he led projects in robotics, wireless power and wireless sensing. At Intel, he founded the Wireless Resonant Energy Link (WERL) project, which demonstrated wireless transfer of tens of watts of power. He also began the Wireless Identification and Sensing Platform (WISP) project, which is a battery-free platform for sensing and computation. It consists of a fully-programmable 16 bit microcontroller that is powered wirelessly by radio waves. It harvests all the energy it needs from a standards-compliant UHF RFID reader and receives and sends data to and from the RFID reader. The WISP platform is used by many researchers around the country and a conference around this work has emerged. At Intel he also co-founded the Personal Robotics project, a collaboration between Intel Research Seattle, Intel Research Pittsburgh, and colleagues at the University of Washington and Carnegie Mellon University. At Intel he conducted research E-Field Pretouch for robot hand preshaping (video link), and arm alignment and grasping (video link). He and his electric field-sensing robot Marvin helped German Chancellor Angela Merkel, California Governor Arnold Schwarzenegger and Intel Chairman Craig Barrett launch CeBIT in 2009. He also developed a method for a robot to "plug itself in" to an ordinary electrical outlet, by sensing the 60Hz electric field emitted from the outlet. video.

Early Professional Research
After finishing his PhD, Josh Smith became Director of Escher Labs, which developed sensing, signal processing, and security technologies for pervasive information processing, with an emphasis on adding intelligence to paper documents. There he developed a technology called FiberFingerprint, that takes the next step beyond digital watermarking, enabling copy protection for physical media. Every square centimeter of paper has a unique pattern of hills and valleys. With the proper sensing and signal processing, we can make use of those characteristics for identification and authentication. FiberFingerprint also makes use of the weak signal detection principles used in Electric Field Imaging and data hiding. (Read more at: The Document That Can't be Forged, New York Times. Smith also spent time at Tiax (formerly Arthur D. Little's Technology and Innovation Practice).

Smith completed his PhD at the MIT Media Lab in 1999, under Neil Gershenfeld. His dissertation, Electric Field Imaging,explored "seeing" with electric fields. Smith believes that Electric Field Imaging is a new channel for machine perception that has been overlooked, because humans do not sense electric fields. At MIT he developed signal processing techniques, hardware, and inference algorithms to let machines acquire useful geometrical information from electric field measurements. He also developed The School of Fish, a network of intelligent electrodes designed for Electric Field Imaging, each with its own analog hardware and on-board computing, on a shared communication channel. It is an unusual form of Sensor Network, because the electrodes are not actually capable of sensing individually. Sensing only occurs via pairwise interactions between electrodes, which makes sensing a property of the network itself, not of individual units.
Elesys (formerly NEC Automative Electronics) released a car seat occupant sensing product based directly on Smith's PhD research. The sensing car seat is embedded with electric field sensors to determine the size and body configuration of the occupant in order to make more intelligent airbag firing decisions. The Occupant Position Detection System ships in all Honda cars with side airbags, and a more sophisticated Electric Field Imaging system from Elesys was introduced in GM vehicles beginning in 2004. Here is a televised demonstrationof the Occupant Position Detection System. Motorola also launched an Electric Field Imaging IC, the MC33794 Electric Field Imaging Device, based on Smith's PhD research.
The fact that Electric Field Imaging has so successfully addressed the important problem of automotive passenger sensing is, in Smith's view, proof that alternative sensing mechanisms can enable better machine perceptual systems. While still working on Electric Field Imaging, I realized that the weak signal detection techniques I was using could be applied in a very different setting, digital watermarking or data hiding. My paper Modulation and Information Hiding in Images was one of the first to propose a quantitive model of digital watermarking, and to frame digital watermarking in terms of communications concepts such as signal, noise, bandwidth and jamming margin.

Early Research Projects and Videos

Electric Field Imaging
Electric Field Imaging lets machines inexpensively sense in 3 dimensions, with high precision and fast update rates. For user interface applications, the user does not have to wear or hold anything, because the technique directly measures the bulk conductivity of the human body. It does not require a line of sight to the body being measured---thus a device can see what its user is doing, right through a plastic case or fabric seat cover. The School of Fish below is an Active Network Sensing system I designed and built to for Electric Field Imaging applications.

ElectricFieldMouse Embedded in ordinary Mouse

School of Fish Active Network Sensing System

Product: NEC/Elesys Occupant Sensing System

Digital Watermarking / Steganography

Bringing signal detection techniques from EFI to a new domain, I published a paper on digital watermarking that has turned out to be influential, measured by citations. At Escher, we applied my data hiding methods to create a new form of postage for the nation of Singapore.

Steganographic Postage Symbology for Singapore

Security Data is steganographically encoded in the rectangular color field. Escher calls this symbology SpectraSeal.


Digital Watermarking is limited in that it can't be used to distinguish copies from the original. To overcome this limitation, I invented FiberFingerprint.

Every square centimeter of paper has a unique pattern of hills and valleys, like a human fingerprint. By properly imaging the surface, we can capture an image of the paper's "fingerprint," turn it into a code, and print that code on the item being secured (using a steganographic symbology, or a barcode, etc). If a valid item is copied, the machine readable data in the symbology will be copied, but not the paper's unique charcteristics. Thus when a copied item is verified, the data (encoded in the SpectraSeal) will not match the "fingerprint" of that piece of paper. The New York Times published a
story about this work.




Joshua R. Smith

Milton and Delia Zeutschel Professor, Computer Science and Engineering, Electrical and Computer Engineering

Voice: 206 685 2094

Fax: 206 543 2969

Office: CSE 581 Lab: EE 371

Mailing address:

Allen School of Computer Science and Engineering

Box 352350

185 Stevens Way

University of Washington

Seattle, WA 98195-2350

Administrator: Lisa Merlin