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Optical spectral reflectance sensor and controller

DC
  • US 6,596,996 B1
  • Filed: 07/24/2001
  • Issued: 07/22/2003
  • Est. Priority Date: 07/24/2001
  • Status: Expired due to Term
First Claim
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1. A spectral reflectance sensor for determining the reflectance of a plant comprising:

  • a housing;

    a light source housed in said housing, said light source projecting light of a predetermined wavelength;

    a reflected light receiver including;

    a first photodetector positioned to receive reflected light originating from said light source ambient light compensation means for reducing the effects of ambient light on said first photodetector; and

    a first output;

    a direct light receiver including;

    a second photodetector positioned to receive incident light from said light source; and

    a second output;

    a discriminator for distinguishing the light originating from said light source and reflected by a plant from ambient light; and

    a microprocessor having an input for reading said first output and an input for reading said second output, wherein the reflectance at said predetermined wavelength is proportional to the quotient of the value of said first output divided by the value of said second output.

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