Programmable sensor aperture

• US 5,023,923 A
• Filed: 02/11/1987
• Issued: 06/11/1991
• Est. Priority Date: 02/11/1987
• Status: Expired due to Fees

• Current Assignee: Light Signatures Incorporated
• Original Assignee: Light Signatures Incorporated
• Inventors: Sanner, M. Duane, Wallace, Barry M., Nunley, Leonard J.
• Primary Examiner(s): Razavi, Michael
• Assistant Examiner(s): MANCUSO, JOSEPH
• Application Number:
  US07/013,485
• Time in Patent Office: 1,581 Days
• Field of Search: 382/7, 382/11, 382/24, 382/29, 382/61, 382/63, 382/67, 235/472, 235/474
• US Class Current: 382/175
• CPC Class Codes: G06V 10/22 by selection of a specific region containing or referencing a pattern; Locating or processing of specific regions to guide the detection or recognition
• CPC Class Codes: G07D 7/12 Visible light, infrared or ultraviolet radiation

Abstract

A document to be verified or tested as a possible counterfeit is scanned by a system that optically senses a specific target area or aperture on the document. This area may include material deposited on the document or may be simply the document material. A reference grid is imprinted on the document to locate the same target area to be sensed each time the document is scanned, independent of the transport used to do the scanning. The reference grid is used to locate the target area both vertically and horizontally and signals sensed from the target area are combined to a representative composite.

Claims

1. A system for characterizing a select target area of variable size and location on a document, said select target area being programmable in size and location with respect to a position reference in a larger area on said document, said larger area also encompassing any select target area, said system comprising:

a sensor array means for scanning said larger area of said document to provide pixel signals representative of said larger area encompassing said select target area and said position reference;

position reference detector means connected to receive said pixel signals for providing position reference signals manifesting the location of said position reference with respect to said pixel signals representative of said larger area;

program means for providing select target area signals to indicate the defined size and location of said select target area with reference to said position reference of said document; and

integrator means connected to receive said pixel signal representative of said larger area, said position reference signals and said select target area signals, said integrator means being controlled by said select target area signals and said position reference signals to selectively process those pixel signals that lie within said select target area to provide output signals representative solely of the characteristic of said select target area to identify said document.

2. A system according to claim 1 wherein said sensor array means comprises a columnar array of light-sensitive elements.

3. A system according to claim 2 wherein said sensor array means further includes clock means for sequencing said columnar array to provide said pixel signals.

4. A system according to claim 1 wherein said program means comprises a pulse means for producing a variable control pulse, the time of which indicates the position of said select area with reference to said position reference and the duration of which indicates the dimension of said select area with reference to said position reference.

5. A system according to claim 1 wherein said integrator means comprises means for converting said pixel signals to digital representations.

6. A system according to claim 5 wherein said integrator further includes means for accumulating said digital representations to provide said output.