Raspberry Pi As Speed Camera

Wherever you stand on the topics of road safety and vehicle speed limits it’s probably fair to say that speed cameras are not a universally popular sight on our roads. If you want a heated argument in the pub, throw that one into the mix.

But what if you live in a suburban street used as a so-called “rat run” through route, with drivers regularly flouting the speed limit by a significant margin. Suddenly the issue becomes one of personal safety, and all those arguments from the pub mean very little.

Sample car speed measurements
Sample car speed measurements

[Gregtinkers]’ brother-in-law posted a message on Facebook outlining just that problem, and sadly the local police department lacked the resources to enforce the limit. This set [Gregtinkers] on a path to document the scale of the problem and lend justification to police action, which led him to use OpenCV and the Raspberry Pi camera to make his own speed camera.

The theory of operation is straightforward, the software tracks moving objects along the road in the camera’s field of view, times their traversal, and calculates the resulting speed. The area of the image containing the road is defined by a bounding box, to stop spurious readings from birds or neighbours straying into view.

He provides installation¬†and dependency¬†instructions and a run-down of the software’s operation in his blog post, and the software itself is available on his GitHub account.

We’ve had a lot of OpenCV-based projects but haven’t featured a speed camera before here on Hackaday. But we have had a couple of dubious countermeasures, like that humorous attempt at an SQL injection attack, or a flash-based countermeasure.

SQL Injection Fools Speed Traps and Clears Your Record

Typical speed camera traps have built-in OCR software that is used to recognize license plates. A clever hacker decided to see if he could defeat the system by using SQL Injection…

The basic premise of this hack is that the hacker has created a simple SQL statement which will hopefully cause the database to delete any record of his license plate. Or so he (she?) hopes. Talk about getting off scot-free!

The reason this works (or could work?) is because while you would think a traffic camera is only taught to recognize the license plate characters, the developers of the third-party image recognition software simply digitize the entire thing — recognizing any and all of the characters present. While it’s certainly clever, we’re pretty sure you’ll still get pulled over and questioned — but at least it’s not as extreme as building a flashbulb array to blind traffic cameras…

What do you guys think? Did it work? This image has been floating around the net for a few years now — if anyone knows the original story let us know!