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Determining a number of objects in an IR image

  • US 8,587,657 B2
  • Filed: 04/13/2011
  • Issued: 11/19/2013
  • Est. Priority Date: 04/13/2011
  • Status: Active Grant
First Claim
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1. A method for determining the number of objects in an IR image obtained by an IR imaging system, the method comprising:

  • collecting a total of N intensity values for each pixel in an IR image said intensity values having been collected using an IR imaging system comprising a single IR detection device and a sequentially illuminating N band IR Illuminator, where (N≧

    3), with one fixed filter, said intensity values comprising;


    Ic(i)=α



    λ

    1
    λ

    2
    Isi

    )[TG2

    )Ro

    )+η

    RG

    )]TL

    )D

    )

    +I
    b where i=1 . . . N, such that i is the ith IR band from said illuminator that is sequentially illuminating, α

    is a constant that depends on an angle and distance from said illumination source, an attenuation of an IR wave in the air, and an integration time of said detecting device, Ib is a background intensity, Ro

    ) is a reflectance of an object detected by said detection device, RG

    ) and TG

    ) are a reflectance and a transmittance of glass, otherwise RG

    )=0 and TG

    )=1, constant η

    is a percentage of light reflected from glass and received by said detector, otherwise η

    =0, TL

    ) is a transmittance of said fixed filter, and D(λ

    ) is a responsivity of said detection device;

    determining a classification for each pixel in said IR image using one of;

    a best fitting method of a reflectance, and a correlation method; and

    determining a total number of objects in said IR image based upon said pixel classification.

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