[54] CCD SCANNER HAVING IMPROVED SPECULAR REFLECTION DISCRIMINATION
[75] Inventor: Kurt Hecht, Hartsville, Pa.
[73] Assignee: Accu-Sort Systems, Inc., Telford, Pa.
[21] Appl. No.: 08/790,956 [22] Filed: Jan. 29, 1997
[51] Int. CI.6 G06K 5/00
[52] U.S. CI 250/556; 235/462
[58] Field of Search 250/556, 555,
250/235, 566; 235/462, 472; 382/313
[56] References Cited
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4,782,219 11/1988 Crater 250/566
5,149.948 9/1992 Chisholm 235/462
5,239469 8/1993 Thomas 235/462
5,406,060 4/1995 Gitin 235/462
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FOREIGN PATENT DOCUMENTS
19510257 9/1995 Denmark .
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0690404 1/1996 European Pat. Off. .
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OTHER PUBLICATIONS
Patent Abstracts of Japan, JP 61 201381 A (Ricoh Co. Ltd.), 6 Sep. 1986, see abstract.
Primary Examiner—Que Le
Attorney, Agent, or Firm—-Volpe and Koenig, PC.
[57] ABSTRACT
An optical scanner utilizes two linear CCD detectors and a bandpass means to improve the ability of the scanner to discriminate against specular reflection. A coded symbology is illuminated by a noncoherent light source and light reflected from the coded symbology along a first path strikes the front face of the bandpass means. The bandpass means, functioning as a notch filter, transmits a select bandwidth of light while reflecting all other light onto a first CCD detector. Simultaneously, light reflected from the bar code symbol travels along a second path, at a different angle with respect to the plane of the coded symbology than the first path, is reflected from a mirror onto the back face of the bandpass means. The bandpass means transmits the select bandwidth of light onto a second CCD detector and reflects all other light. The second CCD detector has a notch filter which permits the detection of only the select bandwidth. Since specular reflection is only experienced at a single angle, with respect to the plane of the coded symbology and each CCD detector detects an image at a different angle with respect to the plane of the coded symbology, a complete image can be reconstructed by combining information obtained from both CCD detectors.
11 Claims, 6 Drawing Sheets
