×

Biological detecting system and fingerprint collating system employing same

  • US 5,077,803 A
  • Filed: 09/14/1989
  • Issued: 12/31/1991
  • Est. Priority Date: 09/16/1988
  • Status: Expired due to Term
First Claim
Patent Images

1. A biological object detecting system comprising:

  • means for presenting the surface of a sample for optical scanning and detection as a biological sample;

    a light source for producing a light beam;

    condensing optical means for condensing the light beam from the light source and irradiating the surface of a sample to be detected with a light beam spot;

    imaging optical means for condensing light reflected and scattered by the irradiated portion of the sample and forming an image of the irradiated portion at a predetermined location; and

    photodetector means disposed at the predetermined location for detecting the size of the image of the irradiated portion and, correspondingly, for indicating whether the sample is a biological object or a replica, the photodetector means further comprising;

    a photodetector having a light receiving face disposed at the predetermined location, the face being defined by three adjacent light receiving regions producing respective, independent electrical signal outputs corresponding to the respective levels of light incident thereon, the second region being intermediate the outer, first and third regions, and the imaging optical means forming the image of the irradiated portion of the sample on the light receiving face of the photodetector,a first operational amplifier having a gain k and receiving the respective electrical outputs of the first and third light receiving regions and in response thereto producing an output k (S1 +S3),a second operational amplifier receiving the output of the second light receiving region and of the first operational amplifier and, in response thereto, producing the output, andmeans for determining whether the sample is a biological object or a replica thereof in accordance with the output having a positive or negative value, respectively.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×