HOLOGRAPHIC CHARACTER READER

• US 3,566,137 A
• Filed: 11/28/1967
• Issued: 02/23/1971
• Est. Priority Date: 11/28/1967
• Status: Expired due to Term

• Current Assignee: Charles Q. Lemmond
• Original Assignee: Charles Q. Lemmond
• Inventors: Lemmond, Charles Q.
• Application Number:
  US04/686,188
• Time in Patent Office: 1,183 Days
• US Class Current: 250/550
• CPC Class Codes: B07C 3/14 using light-responsive detecting means for information carriers G06K7/14
• CPC Class Codes: G03H 1/00 Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
• CPC Class Codes: G06V 10/88 Image or video recognition using optical means, e.g. reference filters, holographic masks, frequency domain filters or spatial domain filters

Abstract

Apparatus for recognizing serially viewed characters of a known font of type is achieved by imaging the characters onto a substrate bearing an electrically charged liquid photoconductor medium deformable in accordance with the optical image. When the deformed portion of the medium is rotated into the beam of a pulsed laser, spots are imaged upon a matrix of photodetectors by passing the laser beam emergent from the medium through a multiple spatial filter made by positioning the type for each of the expected characters in a vertical line.

Claims

1. In a graphic character recognition system having essentially real-time recognition capability and including a source of coherent radiation pulses, radiation detecting means positioned in the path of said radiation, spatial filter means interposed between said source of coherent radiation and said radiation detecting means, and media bearing sets of characters to be recognized, the improvement comprising:

a substrate coated with a deformable liquid photoconductor and situated intermediate said source and said filter means;

means for momentarily illuminating each of said media in sequence;

optical means for imaging the set of characters on each medium when illuminated onto a region of the liquid photoconductor coating so as to deform said region accordingly; and

means for situating the deformed region of said coating in the path of said radiation.

2. The character recognition system of claim 1 wherein said means for illuminating sequentially each of said media comprises a flashlamp and means for moving said media in relation to said flashlamp.

3. The character recognition system of claim 1 including means synchronizing said source of coherent radiation pulses with said means for illuminating sequentially each of said media.

4. The character recognition system of claim 2 including means synchronizing said source of coherent radiation pulses and said means for illuminating sequentially each of said media with the rate at which each one of said media is detected.

5. The character recognition system of claim 1 wherein said means for situating the deformed region of said coating in the path of said radiation comprises means mechanically coupled to said substrate for impelling said substrate to transport the deformed region of said coating into the path of said radiation.

6. The character recognition system of claim 5 wherein said substrate comprises a disc and said means for impelling said substrate comprises a synchronous motor.

7. The character recognition system of claim 5 including means for establishing an electrical charge on the surface of said coating in the region of said coating immediately ahead of the location at which said characters are imaged onto said coating.

8. The character recognition system of claim 5 wherein said source of coherent radiation pulses comprises a laser and said radiation detecting means comprises an array of photodetectors.

9. The character recognition system of claim 6 including means for establishing an electrical charge on the surface of said coating immediately ahead of the location at which said characters are imaged onto said coating.