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.

Distributed computing in JavaScript


We’ve heard about the idea of using browsers as distributed computing nodes for a couple years now. It’s only recently, with the race towards faster JavaScript engines in browsers like Chrome that this idea seems useful. [Antimatter15] did a proof of concept JavaScript implementation for reversing hashes. Plura Processing uses a Java applet to do distributed processing. Today, [Ilya Grigorik] posted an example using MapReduce in JavaScript. Google’s MapReduce is designed to support large dataset processing across computing clusters. It’s well suited for situations where computing nodes could go offline randomly (i.e. a browser navigates away from your site). He included a JavaScript snippet and a job server in Ruby. It will be interesting to see if someone comes up with a good use for this; you still need to convince people to keep your page open in the browser though. We’re just saying: try to act surprised when you realize Hack a Day is inexplicably making your processor spike…

[via Slashdot]


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