Remote Image Processing In JavaScript

[Tom] wrote in to tell us about his JavaScript project for motion detection. It ties together two ideas we’ve talked about recently. The first is doing image processing in-browser using Canvas(), which we’ve seen employed in captcha breaking. The second is offloading heavy processing to browsers, which we saw recently in the MapReduce implementation. [Tom] is using JavaScript to compare consecutive images to determine if there’s any motion. He did this as part of MJPG-Streamer, a program for streaming images from webcams. It can run on very limited hardware, but image processing can be very intensive. Doing the image processing in-browser makes up for this limitation and means that a custom client program doesn’t have to be written. You can find the code here and a PDF about the proof of concept.

PDF Redaction Still Not Working

facebook

Facebook’s internal valuation was revealed this week thanks to shoddy PDF redaction. Court documents from a settlement between Facebook and ConnectU showed that Facebook values itself at $3.7 billion, much less than the $15 billion that was speculated during the Microsoft investment. The AP uncovered this by cutting and pasting from the redacted court document. It’s the same thing we showed in our PDF redaction screencast last summer… and it will never cease to be funny.

[photo: Bryan Veloso]

Exposing Poorly Redacted PDFs


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

eyetrack

[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.]