Prof. Dr. Patrick Baudisch


A Touchscreen that Senses Fingerprints

Fiberio takes system security to a new level. Traditional systems are non-secure in the sense that users authenticate too broadly: once users have swept their badge or scanned their fingerprint, the system is open for anyone until the system eventually "auto locks", often minutes later. Fiberio, in contrast, authenticates users continuously in the background--by scanning their fingerprints every time the user interacts with its touchscreen. This allows Fiberio to implement a new authentication model. In this new model, authentication is only good for the very instant the user touches it. This eliminates the need for timeouts and thus the risk of unauthorized access.

How Fiberio is different from the iPhone 5S: on the iPhone 5S (or laptop or workstation or whatever) once a user is logged in, anyone taking the device can access the owner's images and send email from the owner's email account. With Fiberio there is no such risk. Think of it as James Bond's weapon in the movies License to kill or Skyfall--the device cannot be operated except by its owner.

Fiberio is also multi-user capable. Since Fiberio sends authentication information directly to the touched object rather than the entire system, two or more users can interact simultaneously with everyone accessing contents using their own credentials.

Fiberio is a rear-projected tabletop system that identifies users based on their fingerprints during each interaction—unobtrusively and securely. The shown application uses this to verify that the respective user has the authority to perform the current activity, here approve invoices above a certain value. The key that allows Fiberio to display an image and sense fingerprints at the same time is its screen material: a fiber optic plate.

Summary of UIST 2013 paper

We present Fiberio, a rear-projected multitouch table that identifies users biometrically based on their fingerprints during each touch interaction. Fiberio accomplishes this using a new type of screen material: a large fiber optic plate. The plate diffuses light on transmission, thereby allowing it to act as projection surface. At the same time, the plate reflects light specularly, which produces the contrast required for fingerprint sensing. In addition to offering all the functionality known from traditional diffused illumination systems, Fiberio is the first interactive tabletop system that authenticates users during touch interaction—unobtrusively and securely using the biometric features of fingerprints, which eliminates the need for users to carry identification tokens.



Holz, C. and Baudisch, P. Fiberio: A Touchscreen that Senses Fingerprints. In Proceedings of UIST 2013, 10 pages.
 PDF (2.2M) |  Youtube
 http://www.patrickbaudisch.com/publications/bestpapericons/CHIBestPaperAward16px.gif UIST 2013 BEST PAPER AWARD


Fiberio uses a standard diffuse illumination setup, comprising a high-resolution camera, a projector, an illuminant. The screen ("diffuser"), however, is a fiber optic plate, which uniquely enables displaying output as well as scanning fingerprints.

The Fiber optic plate reveals the user's fingerprint upon touching the surface. The fingerprint ridges in contact with the surface appear dark, whereas fingerprint valleys and hovering parts of the finger appear brighter.

Example scenario: A bank manager and clerk approve invoices. (left) When the clerk encounters a bill above his approval limit, Fiberio refuses the payment. (right) The manager completes the transaction, pushing the same button.

Fiberio uses a fiber plate as the screen, which consists of a multitude of very small-diameter glass fibers (6μm). The fiber optic plate blurs all incident light, here exemplified using a dot laser pointer. The fact that the fiber optic plate scatters light into all directions is the basis for a good light diffuser, which is necessary for projecting output on the touchscreen.

Fiberio recognizes touch, but also hovering objects, such as the user's fingers. Fiberio also recognizes fiducial markers that are attached to tangible objects. The marker attached to the shown cube measures only 3mm×3mm.