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Raspberry Pi Car Speed Detector

(gregtinkers.wordpress.com)
187 points mhss | 1 comments | 17 May 16 15:00 UTC | HN request time: 0s | source
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rubyfan ◴[17 May 16 19:49 UTC] No.11716752[source]▶
I wonder if one could figure out other vehicle speeds from a dashboard camera. His method looks like it assumes a stationary view.
replies(2): >>11717265 #>>11718195 #
dan_quixote ◴[17 May 16 20:46 UTC] No.11717265[source]▶
Definitely. The code here assumes that the vehicle's vector is perpendicular to the optical axis. If you had enough information to calculate the vector it would just be a little extra trig to measure the relative speed minus the offset of your vehicle's instantaneous speed. This is easy for side to side movement, a little harder in the depth direction - though you could get some depth info by comparing the size of the car contour at two or more snapshots (smaller indicating that it's moving away). The framerate/resolution of the RasPi setup probably wouldn't make it a good choice for this though.
replies(1): >>11720724 #
1. rubyfan ◴[18 May 16 09:32 UTC] No.11720724[source]▶
So you definitely need to know your own speed to calculate relative speed of other drivers?

I have a dumb dash cam that's just awesome for video but is nothing more than video to a sd card, ie, not a computer. I've always wondered if I could use just the video using familiar objects like stop signs, mile markers or lane markers to determine my own speed.