LINE FINDING SYSTEM AND METHOD FOR CHARACTER RECOGNITION

• US 3,725,862 A
• Filed: 06/25/1971
• Issued: 04/03/1973
• Est. Priority Date: 06/25/1971
• Status: Expired due to Term

• Current Assignee: David C. Roberts
• Original Assignee: David C. Roberts
• Inventors: Roberts, David C.
• Primary Examiner(s): Robinson, Thomas A.
• Assistant Examiner(s): Thesz, Jr., Joseph M.
• Application Number:
  US05/157,047
• Time in Patent Office: 648 Days
• Field of Search: 340/146.3AH,146.3H,146.3D 178/7.7
• US Class Current: 382/292
• CPC Class Codes: G06V 30/10 Character recognition
• CPC Class Codes: G06V 30/12 Detection or correction of errors, e.g. by rescanning the pattern
• CPC Class Codes: G06V 30/146 Aligning or centring of the image pick-up or image-field

Abstract

In an optical character recognition system the position of a line of characters is detected during the period when the recognition system is not reading the characters but is executing an aging scan which is normally used only for moving the recognition beam around to prevent burns on the face of the recognition system video scanner. The line positions are stored for use during the read mode of the recognition system. The positions of lines actually read during the read mode are compared with these stored positions to determine that all lines in stored positions were actually read. If not read, the read mode is re-executed to read these lines.

Claims

1. In an automatic character recognition system of the type in which i. a plurality of lines of characters are optically directed onto a recognition window area of a pick-up device, ii. an electron beam is directed at said window area to interpret the positions and configurations of said lines of characters, iii. said beam is scanned over said window area in a substantially predetermined pattern during intervals when no characters are being recognized to thereby prevent excessive aging of said pick-up device in said window area, and iv. said beam is directed at said window in a recognition pattern during intervals when characters are being recognized, the improvements comprising, a. means for determining and concurrently storing indications of the respective positions of a plurality of said lines of characters during said intervals when no characters are being recognized, said means for determining and storing indications including a storage channel for association with each of said lines, said channel comprising storage means for storing an analog signal, said storage means including an analog signal input terminal, a trigger storage input terminal, and an analog output terminal, means for applying a deflection signal proportional to the position of said beam to said analog signal input terminal, means for applying a signal to said trigger storage input terminal when a previously unstored line position is determined during said intervals when no characters are being recognized if and only if all storage channels prior to, but not including said channels are occupied whereby storage of said deflection signal value is triggered, and means for providing an output signal proportional to the stored deflection signal value at said analog output terminal. b. means for comparison of the respective positions of lines of characters read during said intervals when characters are being recognized with said indications of the respective positions as previously stored, and c. means responsive to said comparison for providing an indication of whether each line having a previously stored position has been read.

2. A system according to claim 1 including means responsive to said respective positions previously stored for successively directing said beam to stored locations of lines for reading the lines at those locations.

3. In a character recognition system, the combination comprising:

a. means for repetitively scanning a plurality of character entities;

b. means for generating, for each character entity, a signal representing its position;

c. a plurality of storage means for storing said generated signals;

d. means responsive to each of said generated signals for determining if the generated signal has already been stored;

e. means responsive to the last-named means for entering into said storage means only those generated signals which have not previously been stored during the repetitive scanning of said document area;

f. means for enabling a first of the plurality of storage means to receive a first of the generated signals for storage therein;

g. means for inhibiting said first of the plurality of storage means from receiving subsequent generated signals after the first of the plurality of storage means has a first of the generated signals stored therein, h. further means associated with each of the additional storage means and corresponding to said means for enabling and said means for inhibiting associated with said first storage means for enabling each of the additional storage means to receive a gEnerated signal and inhibiting the storage means from receiving subsequent signals after a generated signal is stored therein.

4. The combination of claim 3 further comprising:

a. means for passing a recognition scan pattern over the document area, b. means for comparing the current location of the recognition scan pattern against positions of character entities as represented by stored generated signals; and

c. means for enabling the recognition of characters in a character entity when the position of the recognition scan pattern corresponds to the position of one of said character entities.

5. The combination of claim 4 further comprising:

a. means for repetitively passing the recognition scan pattern over the document area;

b. means for producing a disable signal for each character entity whose position has been determined to correspond to a location of said recognition scanning pattern; and

c. means for inhibiting the recognition of characters in each character entity for which a disable signal has been produced.

6. In a character recognition system, a method for locating and storing the positions of character entities on a document, comprising the steps of:

a. repetitively scanning a document area containing a plurality of character antities, b. generating for each character entity a signal representing its position in the area, c. determining, for each generated signal, if the position represented by the generated signal has previously been stored in any of a plurality of storage means, d. storing a generated signal in one of the storage means if a signal corresponding to the position of the detected character entity has not previously been stored;

e. enabling a first of said plurality of storage means to receive a first of the generated signals for storage therein;

f. causing said first of the plurality of storage means to enable a second storage means to store a second generated signal;

g. repetitively passing a recognition scan pattern over the document area, h. producing a disable signal for each character entity whose position has previously been found to correspond to a position of said recognition scan pattern, and i. inhibiting the recognition of characters in each character entity for which a disable signal has been produced.

7. The method of claim 6 further comprising:

a. passing a recognition scan pattern over the document area, b. comparing the current location of the scan pattern against the positions of the character entities represented by the generated signals stored in the plurality of storage means, and c. enabling the recognition of the characters in a character entity when the position of said recognition scan pattern corresponds to the position of one of said character entities.

8. The method of claim 6 wherein said character entities are lines of characters.