Loading ...
Sorry, an error occurred while loading the content.

Re: [SeattleRobotics] Re: i found some info on a LASER RANGE FINDER DESIGN

Expand Messages
  • Peter Balch
    From: dpa_io ... To me, that looks like a line rather than a grid of dots ... AFAIK, Pathfinder and Spirit/Opportunity all use stripes. I think they have 5
    Message 1 of 9 , Nov 6, 2011
    • 0 Attachment
      From: dpa_io
      > Or use structured light to get a grid rather than a line:
      > http://www.seattlerobotics.org/encoder/200110/vision.htm

      To me, that looks like a line rather than a grid of dots

      > like the planetary rovers.

      AFAIK, Pathfinder and Spirit/Opportunity all use stripes. I think they have
      5 laser stripes that can be turned on/off. The camera takes a picture with
      none on then another picture with one of the lasers on and compares them.

      I remember seeing a multiple-stripe system back in the 90s. The problem is
      that if you have lots of stripes then either a displaced stripe can appear
      in the "domain" of the next stripe along. Or the laser and camera are close
      so that can't happen and you get much lower resolution.

      I suggested that they use a grid (i.e. x-stripes and y-stripes) with the
      angular-displacemnt in one axis one tenth of the angular-displacemnt in the
      other axis. That way, the big displacement provides the resolution but the
      small displacement provides disambiguation. Don't know if they ever did it.

      Peter
    • jamericanfreddy
      from this designs i see no IR PASS FILTER SET AT 950MM OR 980MM WAVE LENGTH OF most lasers,outside on direct sunlight or inside lighting can be a problem ,when
      Message 2 of 9 , Nov 7, 2011
      • 0 Attachment
        from this designs i see no IR PASS FILTER SET AT 950MM OR 980MM
        WAVE LENGTH OF most lasers,outside on direct sunlight or inside lighting can be a problem ,when wecam doesnt have any filters

        --- In SeattleRobotics@yahoogroups.com, "Peter Balch" <peterbalch@...> wrote:
        >
        > From: dpa_io
        > > Or use structured light to get a grid rather than a line:
        > > http://www.seattlerobotics.org/encoder/200110/vision.htm
        >
        > To me, that looks like a line rather than a grid of dots
        >
        > > like the planetary rovers.
        >
        > AFAIK, Pathfinder and Spirit/Opportunity all use stripes. I think they have
        > 5 laser stripes that can be turned on/off. The camera takes a picture with
        > none on then another picture with one of the lasers on and compares them.
        >
        > I remember seeing a multiple-stripe system back in the 90s. The problem is
        > that if you have lots of stripes then either a displaced stripe can appear
        > in the "domain" of the next stripe along. Or the laser and camera are close
        > so that can't happen and you get much lower resolution.
        >
        > I suggested that they use a grid (i.e. x-stripes and y-stripes) with the
        > angular-displacemnt in one axis one tenth of the angular-displacemnt in the
        > other axis. That way, the big displacement provides the resolution but the
        > small displacement provides disambiguation. Don't know if they ever did it.
        >
        > Peter
        >
      • dpa_io
        Isn t that what the optical filter described in Diagram does? Depicted symbolically here, the band-pass filter passes the 671nm wave length of interest while
        Message 3 of 9 , Nov 7, 2011
        • 0 Attachment
          Isn't that what the optical filter described in Diagram does?

          "Depicted symbolically here, the band-pass filter passes the 671nm wave length of interest while blocking other spectral content."

          -D


          --- In SeattleRobotics@yahoogroups.com, "jamericanfreddy" <jamericanfreddy@...> wrote:
          >
          > from this designs i see no IR PASS FILTER SET AT 950MM OR 980MM
          > WAVE LENGTH OF most lasers,outside on direct sunlight or inside lighting can be a problem ,when wecam doesnt have any filters
          >
          > --- In SeattleRobotics@yahoogroups.com, "Peter Balch" <peterbalch@> wrote:
          > >
          > > From: dpa_io
          > > > Or use structured light to get a grid rather than a line:
          > > > http://www.seattlerobotics.org/encoder/200110/vision.htm
          > >
          > > To me, that looks like a line rather than a grid of dots
          > >
          > > > like the planetary rovers.
          > >
          > > AFAIK, Pathfinder and Spirit/Opportunity all use stripes. I think they have
          > > 5 laser stripes that can be turned on/off. The camera takes a picture with
          > > none on then another picture with one of the lasers on and compares them.
          > >
          > > I remember seeing a multiple-stripe system back in the 90s. The problem is
          > > that if you have lots of stripes then either a displaced stripe can appear
          > > in the "domain" of the next stripe along. Or the laser and camera are close
          > > so that can't happen and you get much lower resolution.
          > >
          > > I suggested that they use a grid (i.e. x-stripes and y-stripes) with the
          > > angular-displacemnt in one axis one tenth of the angular-displacemnt in the
          > > other axis. That way, the big displacement provides the resolution but the
          > > small displacement provides disambiguation. Don't know if they ever did it.
          > >
          > > Peter
          > >
          >
        • jamericanfreddy
          yes in this article yes http://www.seattlerobotics.org/encoder/200110/vision.htm#sec2 but in others just webcam and laser one when i was checking out bandpass
          Message 4 of 9 , Nov 7, 2011
          • 0 Attachment
            yes in this article yes
            http://www.seattlerobotics.org/encoder/200110/vision.htm#sec2
            but in others just webcam and laser
            one when i was checking out bandpass IR filter at edmund optics prices are very high,plus webcam and then lasers,if you read the article on parallax design the guy who made tested a few lasers, and other tests and uses a special camera and adddd a optic IR bandpass lens
            so what it comes down to is a compete LASER RANGING circuit without getting a laser,plus webcam ,plus OPTICS and build it your self and hope it has good accuracy

            dont think it is good as $300 to $3000 LIDAR system ,but looks better then homemade design for less $$$
            i built the first design link on just a webcam and laser and results was bad,lighting was a problem and webcam video not so great(tracking)
            in second by seattle groups encoder design does look alot better,but at high costs

            --- In SeattleRobotics@yahoogroups.com, "dpa_io" <davida@...> wrote:
            >
            >
            >
            > Isn't that what the optical filter described in Diagram does?
            >
            > "Depicted symbolically here, the band-pass filter passes the 671nm wave length of interest while blocking other spectral content."
            >
            > -D
            >
            >
            > --- In SeattleRobotics@yahoogroups.com, "jamericanfreddy" <jamericanfreddy@> wrote:
            > >
            > > from this designs i see no IR PASS FILTER SET AT 950MM OR 980MM
            > > WAVE LENGTH OF most lasers,outside on direct sunlight or inside lighting can be a problem ,when wecam doesnt have any filters
            > >
            > > --- In SeattleRobotics@yahoogroups.com, "Peter Balch" <peterbalch@> wrote:
            > > >
            > > > From: dpa_io
            > > > > Or use structured light to get a grid rather than a line:
            > > > > http://www.seattlerobotics.org/encoder/200110/vision.htm
            > > >
            > > > To me, that looks like a line rather than a grid of dots
            > > >
            > > > > like the planetary rovers.
            > > >
            > > > AFAIK, Pathfinder and Spirit/Opportunity all use stripes. I think they have
            > > > 5 laser stripes that can be turned on/off. The camera takes a picture with
            > > > none on then another picture with one of the lasers on and compares them.
            > > >
            > > > I remember seeing a multiple-stripe system back in the 90s. The problem is
            > > > that if you have lots of stripes then either a displaced stripe can appear
            > > > in the "domain" of the next stripe along. Or the laser and camera are close
            > > > so that can't happen and you get much lower resolution.
            > > >
            > > > I suggested that they use a grid (i.e. x-stripes and y-stripes) with the
            > > > angular-displacemnt in one axis one tenth of the angular-displacemnt in the
            > > > other axis. That way, the big displacement provides the resolution but the
            > > > small displacement provides disambiguation. Don't know if they ever did it.
            > > >
            > > > Peter
            > > >
            > >
            >
          Your message has been successfully submitted and would be delivered to recipients shortly.