MULTIPLE SCANNER CHARACTER READING SYSTEM

• US 3,806,871 A
• Filed: 04/13/1971
• Issued: 04/23/1974
• Est. Priority Date: 01/30/1968
• Status: Expired due to Term

• Current Assignee: David H Shepard
• Original Assignee: David H Shepard
• Inventors: Shepard, David H.
• Primary Examiner(s): Henon, Paul J.
• Assistant Examiner(s): Boudreau, Leo H.
• Application Number:
  US05/133,690
• Time in Patent Office: 1,106 Days
• Field of Search: 340/146.3,150 178/7.1,7.2
• US Class Current: 382/311
• CPC Class Codes: G06T 1/0007 Image acquisition
• CPC Class Codes: G06V 10/10 Image acquisition document image scanning and transmission H04N1/00; control of digital cameras H04N23/60
• CPC Class Codes: G06V 10/98 Detection or correction of errors, e.g. by rescanning the pattern or by human intervention; Evaluation of the quality of the acquired patterns

Abstract

A system comprising a central station having data processing apparatus with a common data buss arrangement interconnecting a data processor with its peripheral devices including a number of incoming data buffers. A plurality of remote desk-top scanner units are connected to the central station, each being arranged to receive a document bearing graphic characters and to scan the characters on the document with an optical light beam so as to sweep the character area in a series of adjacent paths. Each remote scanner has means to develop scan signals representing the light reflected from the scanned document and to produce binary code groups indicating the scan distances between certain selected events such as white-to-black transitions. The code groups from each remote scanner are transmitted to a respective data buffer at the central station and subsequently are decoded to reconstruct the original video scan data in a form suitable for deciphering by character recognition means so as to identify the individual characters of the document. The central data processing apparatus, including decoding and character recognition means, operates on a time-sharing basis to service all of the remote units.

Claims

1. The method of reading graphic characters on documents at a plurality of separated locations, comprising the steps of:

concurrently scanning documents at said separated locations in a series of consecutive, closely-adjacent and uniformly-spaced scan paths covering the full area containing the characters to be read;

developing from said scanning operations, and concurrently therewith, binary scan signals indicating the presence or absence of character elements at uniformly-spaced positions along the scan paths;

concurrently transmitting from said locations to a central receiving station data signals corresponding to the respective scan signals, the transmission of data signals from any given one of said locations being effected concurrently with the development of the scan signals from that location;

storing information signals corresponding to the data signals from each location in a respective storage means at said receiving station, the storage being effected essentially simultaneously with the receipt of the signals and the storing of the data signals from all said locations occurring concurrently; and

analyzing information signals in any storage means in which has been accumulated signals of a predetermined amount representing at least one character to be identified, so as to produce output signals identifying such character.

2. The method of claim 1, including the step of coding the binary scan signals in such a fashion as to produce data signals containing the original scan data but capable of transmission through a limited band-width transmission channel in less time than would be required for the transmission through such channel of the original binary scan signals.

3. The method of claim 1, including the step of determining when any character cannot be identified by analysis of the stored signals;

and utilizing signals derived from the accumulated stored signals to develop a visual image display of the unidentifiable character, to permit visual idenTification of such character, together with a series of characters adjacent the unidentifiable character in the line of characters which includes such unidentifiable character.

4. The method of claim 1, for reading graphic characters in line format, wherein the binary scan signals indicate the presence or absence of character elements at the intersections of an orthogonal matrix encompassing all of the characters to be read in each line of characters being scanned;

storing in a digital storage means binary data signals corresponding to the binary scan signals from respective locations until data signals are accumulated representing a complete line of characters at any one location; and

analyzing said accumulated data signals presented as a series of sequences of binary data bits representing a series of vertical sweeps through the intersections of said orthogonal matrix encompassing said accumulated increment of data, to produce output signals identifying in succession each of the characters in the line.

5. The method of reading graphic characters on a document bearing characters in line format, comprising the steps of:

scanning the document with consecutive, closely-adjacent scanning-spot sweeps parallel to and completely traversing the line of characters to be read, said sweeps defining a series of parallel scan paths which are uniformly-spaced and which completely cover the area occupied by the line of characters to be read, the center-to-center spacing between consecutive scan paths being uniform and at least approximately the same as the size of the scanning spot so as to scan the area fully yet efficiently, the number of such successive sweeps being sufficient to scan all of the characters in the line;

developing from said scanning operation binary scan sample signals indicating the presence or absence of character elements at uniformly-spaced sample points along each scan path, the sample points in the successive scan paths being aligned so that the scan sample signals for the complete series of scanning sweeps reflect the presence or absence of character elements at the intersections of an orthogonal matrix encompassing all of the characters to be read in the line being scanned;

storing in a digital storage means binary data signals corresponding to said binary scan sample signals until data signals are accumulated representing a complete line of characters; and

analyzing said accumulated data signals presented as a series of sequences of binary data bits representing a series of sequences of vertical sweeps through the intersections of said orthogonal matrix encompassing said accumulated increment of data, to produce output signals identifying in succession each of the characters in the line.

6. In a character reading system of the type comprising a central station, a plurality of remote units having means to receive a document bearing characters to be read;

scan means forming part of each remote unit and arranged to trace scan paths on the document and to produce sequential sample signals indicating the presence or absence of character elements at points along each path; and

circuit means at each of said remote units responsive to said sample signals and operable to produce corresponding output signals suitable for transmission to said central station;

that improvement wherein said system further comprises a plurality of continuously operating signal channels for said remote units respectively and arranged to direct the output signals of all of said remote units concurrently to said central station;

said central station including a plurality of effectively concurrently operable temporary storage means for receiving and storing signals corresponding to the output signals from said remote units at least essentially simultaneously with receipt of the signals at the central station;

means at said central station for directing the signals received from said channels to respective segments of said temporary storage meAns assigned thereto to store the signals essentially at the time of receipt in a storage location identifiable with a corresponding remote scanner, whereby the remote scanners can be operated concurrently to develop and send their respective output signals over their corresponding signal channels simultaneously so as to provide efficient utilization of the remote units and the signal channels; and

character recognition means at said central station operable on a time-sharing basis to read out from any of said temporary storage means signals representing accumulated scan data for any one remote unit when such accumulated data is a predetermined increment representing at least one complete character, said character recognition means serving to analyze such signals to identify each individual character of the scanned documents.

7. Apparatus as claimed in claim 6, wherein the scan means at each remote unit includes means to repetitively sweep a scanning spot across the document to define a series of closely adjacent parallel scan paths, the size of the scanning spot being at least approximately equal to the center-to-center spacing of adjacent scan paths so as to cover the full area containing the characters to be read.

8. Apparatus as claimed in claim 7, including sampling means to produce scan sample signals at points uniformly spaced along each scan path.