Processor based method for extracting tablets from printed documents

• US 5,956,422 A
• Filed: 02/21/1998
• Issued: 09/21/1999
• Est. Priority Date: 10/20/1995
• Status: Expired due to Fees

• Current Assignee: BCL Computers Incorporated
• Original Assignee: BCL Computers Incorporated
• Inventors: Alam, Hassan
• Primary Examiner(s): Shalwala, Bipin H.
• Application Number:
  US09/010,394
• Time in Patent Office: 577 Days
• Field of Search: 382/181, 382/171, 382/173, 382/174, 382/175, 382/176, 382/180, 382/286, 382/291, 382/295, 382/305, 382/306, 382/193, 382/194, 382/197, 382/199, 382/202
• US Class Current: 382/181
• CPC Class Codes: G06V 30/10 Character recognition
• CPC Class Codes: G06V 30/1444 Selective acquisition, locating or processing of specific regions, e.g. highlighted text, fiducial marks or predetermined fields
• CPC Class Codes: G06V 30/412 Layout analysis of documents structured with printed lines or input boxes, e.g. business forms or tables

Abstract

A processor based method for recognizing, capturing and storing tabular data receives digital-computer data representing a document either as a pixel-format document-image, or as formatted text. Within the digital computer, either form of the digital-computer data is processed to locate tabular data present therein. After a table has been located, tabular data is extracted from cells present in either form of the digital-computer data. The extracted tabular data is stored into a database present on the digital computer.

Claims

1. A processor-based method for recognizing, capturing and storing into a database file unruled tabular data of a document, the document having at least one page, the method comprising the steps of:

receiving into a digital computer digital-computer data representing a document;

processing within the digital computer the digital-computer data to locate unruled tabular data present therein;

extracting the unruled tabular data from cells present in the digital-computer data; and

storing into a database file present on the digital computer the extracted tabular data.

2. The processor-based method of claim 1 wherein the digital-computer data is received as a pixel-format document-image.

3. The processor-based method of claim 2 wherein optical character recognition is performed directly on a received pixel-format document-image to obtain formatted text, and the formatted text obtained by optical character recognition is processed to locate unruled tabular data present therein.

4. The processor-based method of claim 2 wherein the pixel-format document-image is processed directly to locate unruled tabular data present therein.

5. The processor-based method of claim 4 wherein processing the pixel-format document-image directly to locate unruled tabular data present therein includes the steps of:

evaluating a horizontal projection profile of the pixel-format document-image;

determining upper and lower boundaries of a table by analyzing white space disclosed by the horizontal projection profile;

evaluating a vertical projection profile of the pixel-format document-image; and

determining a horizontal location of the table by analyzing white space disclosed by the vertical projection profile.

6. The processor-based method of claim 5 wherein optical character recognition is performed to obtain formatted text of the pixel-format document-image for which upper and lower boundaries and a horizontal location have been determined, and the formatted text obtained by optical character recognition is further processed to locate unruled tabular data present therein.

7. The processor-based method of claim 5 wherein unruled tabular data located in a pixel-format document-image is extracted directly from cells present in the pixel-format document-image, and further including the step of:

before storing the tabular data into the database file present on the digital computer, performing optical character recognition on pixel-format document-images extracted from the cells to obtain the tabular data.

8. The processor-based method of claim 7 wherein extracting the unruled tabular data from cells present in the pixel-format document-image includes the steps of:

establishing regions in the pixel-format document-image using connected component analysis;

evaluating a vertical projection profile of the regions to determine plumb lines between regions; and

using the regions and plumb lines, determining cells from which pixel-format document-images are extracted for optical character recognition processing.

9. The processor-based method of claim 1 wherein the digital-computer data is received as formatted text.

10. The processor-based method of claim 1 wherein the digital-computer data is formatted text present in a text file which is processed to locate unruled tabular data present therein.

11. The processor-based method of claim 10 wherein processing the formatted text to locate unruled tabular data present therein includes the steps of:

scanning the formatted text to identify a line containing a keyword;

determining that the line containing the keyword is a first horizontal boundary of a table;

determining a horizontal location of the table on the page; and

determining a second horizontal boundary of the table.

12. The processor-based method of claim 11 wherein processing the formatted text to locate unruled tabular data present therein further includes the steps of:

locating a small table in the formatted text;

determining a horizontal location of the table on the page; and

determining upper and lower boundaries for the table.

13. The processor-based method of claim 10 wherein processing the formatted text to locate unruled tabular data present therein includes the steps of:

locating a small table in the formatted text;

determining a horizontal location of the table on the page; and

determining upper and lower boundaries for the table.

14. The processor-based method of claim 1 wherein the digital-computer data is formatted text in which unruled tabular data has been located, and the unruled tabular data is extracted from cells present in the formatted text.

15. The processor-based method of claim 14 wherein extracting unruled tabular data located in formatted text from cells present in the formatted text includes the steps of:

establishing white-space-interval vectors for all text lines in which unruled tabular data has been located; and

forming a white-space-vector intersection by intersecting the white-space-interval vectors for all white-space-interval vectors having more than two white-space intervals.

16. The processor-based method of claim 15 wherein extracting unruled tabular data located in formatted text from cells present in the formatted text further includes the step of:

forming an augmented white-space-vector intersection by intersecting with the white-space-vector intersection a white-space-interval vector having only two white-space intervals; and

if the augmented white-space-vector intersection has no fewer white-space intervals than the white-space-vector intersection, then replacing the white-space-vector intersection with the augmented white-space-vector intersection.