On Aug 7 2015 5:32 PM, Peter C. Wallace wrote: > On Fri, 7 Aug 2015, EBo wrote: > >> Date: Fri, 07 Aug 2015 17:13:25 -0600 >> From: EBo <e...@sandien.com> >> Reply-To: EMC developers <emc-developers@lists.sourceforge.net> >> To: emc-developers@lists.sourceforge.net >> Subject: Re: [Emc-developers] research on optical encoders >> >> On Aug 7 2015 4:16 PM, andy pugh wrote: >>> On 7 August 2015 at 12:23, EBo <e...@sandien.com> wrote: >>>> Possibly, but I cannot tell from the information Renishaw >>>> published >>>> in >>>> that brochure. >>> >>> I think that the target is a barcode. The head can see enough >>> barcode >>> to tell exactly where it is on the code sequence to within one bar, >>> then looks at the absolute position of the bars in the viewing area >>> to work out the rest of the bits of data. >> >> I think it is following on the same idea roughly. Looking at the >> renshaw they claim it can give you 1nm (1e-9m) or 3.9e-8 inches >> precision. I have no idea how they are pulling that off besides >> laser >> interferometry and ring counting. Can you suggest another method >> that >> would work? > > AFAIK they dont use a laser, just a bright LED thats pulsed to take a > snapshot > of the barcode, probably with a rather high resolution linear sensor > array (or > multiple arrays with pixel interleaving) > > Quite high-sub pixel interpolation should possible with such a setup > because > of all the duplicated edges
agreed with the laser/LED. I would have to study sub pixel interpolation to see how much additional interpolation you could get. ------------------------------------------------------------------------------ _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
