[time-nuts] position determination over short distance

[Bruce Griffiths]

Tom Van Baak wrote:
>> I need to determine the position of a instrument with a 1mm accuracy or less.
>> The instrument is not connected to a mechanical device but is separate &
>> independent.
>> The surface which the instrument is positioned on is close to the size of a
>> 11"x11" square.
>>     
>
> 1 mm or better accuracy on a 300x300 mm surface can be
> obtained with a cheap webcam mounted above the surface
> and a little bit a creative software.
>
> /tvb
>   
Dont forget to calibrate the camera distortion and ensure that this
doesnt over over time.

i.e. lock the focus and ensure the camera position, tilt etc with
respect to the reference surface do not vary.

Bruce