Exposing Poorly Redacted PDFs

August 1, 2008 by Eliot 19 Comments

Privacy watchdog group, National Legal and Policy Center has released a PDF detailing Google founder Larry Page’s home (dowload PDF here). They used Google’s Maps and Street View to assemble all of the information. Google is currently involved in a lawsuit resulting from a Street View vehicle traveling and documenting a private road. This PDF was released in response to Google stating that “complete privacy does not exist”.

For some reason the PDF is redacted with black boxes. We threw together a simple screencast (click through for HiDef) to show how to easily bypass the boxes using free tools. You can simply cut and paste the hidden text and images can be copied as well-no need to break out Illustrator. This sort of redaction may seem trivial, but the US military has fallen victim to it in the past.

Lightweight Eye Tracker

January 13, 2006 by Eliot 15 Comments

[Jason S. Babcock] and [Jeff B. Pelz] put together this paper on building a simple, lightweight eyetracker (PDF) to foster the creation of open source eyetracking software. All of the components are mounted to a cheap pair of safety glasses. The eyetracker uses a technique called “dark-pupil” illumination. An IR LED is used to illuminate the eye. The pupil appears as a dark spot because it doesn’t reflect the light. A bright spot also appears on the cornea where the IR is directly reflected. An eye camera is mounted next to the IR LED to record the image of eye with these two spots. Software tracks the difference between the two spots to determine the eye orientation. A laser mounted to the frame helps with the initial calibration process. A scene camera placed above the eye records what the eye is viewing. The video from these two cameras can be compared in real time or after the experiment is concluded.

[thanks austin y.]