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Methods for enhancing performance and data acquired from three-dimensional image systems

  • US 6,512,838 B1
  • Filed: 10/05/2000
  • Issued: 01/28/2003
  • Est. Priority Date: 09/22/1999
  • Status: Expired due to Term
First Claim
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1. For use with a system that acquires distance and brightness measurements using energy transmitted from an emitter at a first location on a plane, said energy reflecting at least in part from a target object and being detected by independent sensors defining a sensor array on said plane but spaced-apart from said first location, a method of improving actual (x,y,z) measurement by correcting elliptical error of a system including said energy transmitter and sensor array, the method comprising the following steps:

  • (a) defining a spherical coordinate for said sensors in said sensor array, and constructing a look-up table containing spherical coordinates for each of said sensors, where a spherical coordinate for sensor Pij is given by (pij,−

    aij,−

    bij);

    (b) defining a spatial coordinate of said emitter from a spherical coordinate system defined in step (a) such that said spatial coordinate of said emitter has a same origin as said spherical coordinate system, where said spatial coordinate of said emitter is (Cx, Cy, Cz) and defining a constant k as square of distance between said emitter and said origin of said spherical coordinate system;

    (c) For each sensor Pij, constructing a look-up table of a constant hij where hij is calculated as follows;



    hij=2(pij+Cx cos(aij)sin(bij)+Cy sin(aij)sin(bij)+Czcos(bij))where (pij, −

    aij, −

    bij) is the spherical coordinate of said sensor Pij defined at step (a), and where (Cx, Cy, Cz) is the spatial Cartesian coordinate of said emitter defined at step (b);

    (d) identifying sensors {circumflex over (P)}ij that actually detect energy reflected from said target object;

    (e) using measured rountrip distance dij from said emitter to sensors {circumflex over (P)}ij identified at step (d) to calculate distance rij from an imaging portion of said target object and said sensor {circumflex over (P)}ij according to rij=((dij

    pij)2

    k)/(2dij

    hij), using values of k determined at step (b), values of hij determined in step (c), and {circumflex over (p)}ij determined in step (a); and

    (f) calculating actual Cartesian coordinate (Ax, Ay, Az) of imaging portion of said target objection according to Ax=rij cos(â

    ij)sin({circumflex over (b)}ij), Ax=rij sin(â

    ij)sin({circumflex over (b)}ij), and Ax=rij cos({circumflex over (b)}ij), where rij is obtained in step (e) and â

    ij, {circumflex over (b)}ij of sensor {circumflex over (P)}ij are obtained in step (a).

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