For my device moving above the surface (railway tracks) I need to be measuring the distance traveled. So far I have been using a wheel with IRC (incremental rotary sensor). To simplify it I would like to use some kind of optical sensor that scans the surface.
I have seen some ideas using optical mouse sensors for the distance measurement, however, it is not clear to me where this would take the reference for determination of the actual distance by which the sensor has moved over the surface.
Is there any such optical sensor?
Best Answer
Yes. It is called optical flow sensor. There is a also a free source community (not sure) that develops and sells such device. https://pixhawk.org/modules/px4flow
https://pixhawk.org/_media/modules/px4flow_paper.pdf
For example you could mount the camera on top of the railway wagon with known distance from ground and illuminate the surface with LED lamp (if you wish to measure at low light). Such setup will be more precise if the surface isn't flat, all you have to do is to use lens with more magnification. More height -> more magnification -> better precision.
But you can make it from scratch using optical mouse sensor with adapted lens.