Symbol information reading apparatus

• US 5,525,787 A
• Filed: 08/18/1994
• Issued: 06/11/1996
• Est. Priority Date: 11/11/1991
• Status: Expired due to Term

• Current Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Original Assignee: Olympus Optical Company Ltd. (Olympus Corporation)
• Inventors: Kubo, Mitsunori
• Primary Examiner(s): PITTS, HAROLD I
• Application Number:
  US08/292,602
• Time in Patent Office: 663 Days
• Field of Search: 235/472, 235/462, 235/494, 235/470
• US Class Current: 235/462.09
• CPC Class Codes: G06K 7/1093 sensing, after transfer of the image of the data-field to an intermediate store, e.g. storage with cathode ray tube

Abstract

A bar code symbol picked-up by a two-dimensional image pickup device is stored in a frame memory. A data processing unit automatically recognizes whether the bar code symbol is present or not, based on the information stored in the frame memory, that is, the image pickup data. If the bar code symbol is present, the information of the bar code symbol projected on a photoelectric conversion surface of the two-dimensional image pickup device is read and decoded to the original information. The bar code symbol can be recognized automatically by the following methods of monitoring a variation in density of the image pickup data, monitoring a spatial frequency component of the image pickup data, monitoring whether a predetermined bar code pattern is formed in the image pickup data, monitoring widths of bars and spaces in the image pickup data, monitoring the number of edges of bars and spaces in the image pickup data, monitoring a correlation among the image pickup data obtained by a plurality of image pickup operations of the image pickup device, etc.

Claims

1. A symbol information reading apparatus for recognizing whether a bar code symbol including bars and spaces is present, and for thereafter reading the bar code symbol, the apparatus comprising:

an image pickup device for picking up an entire image of the bar code symbol and for outputting image pickup data;

recognizing means for detecting a frequency of pixels corresponding to widths of the bars and spaces of the picked up image of the bar code symbol, based on the image pickup data received from said image pickup device, and for automatically recognizing whether a bar code symbol is present according to whether peaks of the widths having a frequency exceeding a predetermined threshold value have a predetermined interval; and

instruction means for issuing an instruction to start decoding information supplied from said image pickup device only when said recognizing means recognizes that the bar code symbol is present.

2. The apparatus according to claim 1, wherein said predetermined interval of the peaks of the widths is a substantially constant value.

3. The apparatus according to claim 1, further comprising decoding means for decoding the information supplied from said image pickup device in response to the instruction issued from said instruction means.

4. A. A symbol information reading apparatus for recognizing whether a bar code symbol including bars and spaces is present, and for thereafter reading the bar code symbol, the apparatus comprising:

an image pickup device for picking up an entire image of the bar code symbol and for outputting image pickup data;

recognizing means for detecting a frequency of pixels corresponding to widths of the bars and spaces of the picked up image of the bar code symbol, based on the image pickup data received from said image pickup device, and for automatically recognizing whether a bar code symbol including bars and spaces is present according to whether;

peaks of the widths having a frequency exceeding a predetermined threshold value have a predetermined interval having a minimum width,

there are six peaks of the widths, and

a maximum width of a bar or space is six times as large as the minimum width thereof; and

instruction means for issuing an instruction to start decoding information supplied from said image pickup device only when said recognizing means recognizes that the bar code symbol is present.

5. The apparatus according to claim 4, wherein said predetermined interval of the peaks of the widths is a substantially constant value.

6. The apparatus according to claim 4, further comprising decoding means for decoding the information supplied from said image pickup device in response to the instruction issued from said instruction means.