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Object profile measuring method and apparatus

  • US 5,739,912 A
  • Filed: 12/20/1996
  • Issued: 04/14/1998
  • Est. Priority Date: 04/26/1991
  • Status: Expired due to Fees
First Claim
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1. A method for measuring an external profile of an object in robotic arc-welding, said method being based on triangulation operations and capable of performing a measurement under existence of arc light with fluctuating intensity at relatively low frequency, said method for measuring an external profile comprising the steps of:

  • intermittently emitting a laser beam onto a surface of said object at a sufficiently shorter time interval than a fluctuation period of intensity of the arc-light;

    repeatedly sensing reflected light from said surface during a predetermined sensing period in synchronism with emission of the laser beam, by means of a plurality of charge storage type light receiving elements arrayed in line;

    generating output signals responsive to said reflected laser beam and to the arc light;

    generating delayed signals, for said output signals, delayed by one line period of the charge storage type light receiving array;

    obtaining difference values between said output signals and said delayed signals so that said difference values are indicative of the difference between output signals while said laser beam is on and while said laser beam is off to enable elimination of influence of said arc light; and

    determining positions of points on said surface based on said difference values.

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