Apparatus and methods for converting network drawings from raster format to vector format

• US 20040151377A1
• Filed: 02/04/2003
• Published: 08/05/2004
• Est. Priority Date: 02/04/2003
• Status: Abandoned Application

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Boose, Molly L., Shema, David B.
• Application Number:
  US10/357,847
• Publication Number:
  US 20040151377A1
• Time in Patent Office: Days
• US Class Current: 382/193
• CPC Class Codes: G06V 30/422 Technical drawings; Geographical maps

Abstract

Apparatus and methods for converting a network drawing from raster format to vector format. The method involves recognizing text within a raster image by using optical character recognition and a character set associated with the raster image. The recognized text is extracted from the raster image to produce a text-only raster image and a text-stripped raster image. The method further includes recognizing graphic objects within the text-stripped raster image by using pattern recognition with image-specific parameters to identify graphic objects. Recognized graphic objects are represented with vector graphical primitives to produce a text-stripped vector image. Vector text elements corresponding to the extracted text are added into the text-stripped vector image to produce a vector image that is substantially identical in appearance to the raster image.

Claims

1. A method for converting network drawings from raster format to vector format, the method comprising:

recognizing text within a raster image by using optical character recognition and a character set associated with the raster image, the raster image comprising a network drawing in raster format;

extracting the recognized text to produce a text-only raster image and a text-stripped raster image;

recognizing graphic objects within the text-stripped raster image by using pattern recognition and image-specific parameters associated with the raster image,

using vector graphical primitives corresponding to the recognized graphic objects to produce a text-stripped vector image; and

adding vector text elements corresponding to the extracted text into the text-stripped vector image to produce a vector image substantially identical in appearance to the raster image.

2. The method of claim 1, wherein recognizing graphic objects within the text-stripped raster image comprises recognizing less ambiguous graphic objects before recognizing more ambiguous graphic objects.

3. The method of claim 1, wherein recognizing graphic objects within the text-stripped raster image comprises noise smoothing.

4. The method of claim 1, wherein recognizing graphic objects within the text-stripped raster image comprises:

building a list of two-dimensional pixel runs;

recognizing lines from the list of two-dimensional pixel runs;

removing from the list of two-dimensional pixel runs the pixel runs recognized as lines;

recognizing binary large objects from the list of two-dimensional pixel runs; and

recognizing graphic objects from the recognized binary large objects by matching each binary large object with its corresponding vector graphical primitive.

5. The method of claim 4, wherein building a list of two-dimensional pixel runs comprises:

merging pixel runs having identical x-coordinates and adjacent y-coordinates to create two-dimensional pixel runs; and

removing the pixel runs merged with another pixel run from the list of two-dimensional pixel runs.

6. The method of claim 4, further comprising repairing binary large objects split by pixel removal during line recognition.

7. The method of claim 1, further comprising defining the image-specific parameters.

8. The method of claim 1, wherein the raster image comprises a wiring diagram in raster format.

9. A system for converting network drawings from raster format to vector format, the system comprising:

a computer executable module for recognizing text within a raster image by using optical character recognition and a character set associated with the raster image, the raster image comprising a network drawing in raster format;

a computer executable module for extracting the recognized text to produce a text-only raster image and a text-stripped raster image;

a computer executable module for recognizing graphic objects within the text-stripped raster image by using pattern recognition and image-specific parameters associated with the raster image,

a computer executable module for using vector graphical primitives corresponding to the recognized graphic objects to produce a text-stripped vector image; and

a computer executable module for adding vector text elements corresponding to the extracted text into the text-stripped vector image to produce a vector image substantially identical in appearance to the raster image.

10. The system of claim 9, wherein the computer executable sub-module for recognizing graphic objects within the text-stripped raster image comprises a computer executable sub-module for recognizing less ambiguous graphic objects before recognizing more ambiguous graphic objects.

11. The system of claim 9, wherein the computer executable module for recognizing graphic objects within the text-stripped raster image comprises a computer executable sub-module for noise smoothing.

12. The system of claim 9, wherein the computer executable module for recognizing graphic objects within the text-stripped raster image comprises:

a computer executable sub-module for building a list of two-dimensional pixel runs;

a computer executable sub-module for recognizing lines from the list of two-dimensional pixel runs;

a computer executable sub-module for removing from the list of two-dimensional pixel runs the pixel runs recognized as lines;

a computer executable sub-module for recognizing binary large objects from the list of two-dimensional pixel runs; and

a computer executable sub-module for recognizing graphic objects from the recognized blobs by matching each binary large object with its corresponding vector graphical primitive.

13. The system of claim 12, wherein the computer executable sub-module for building a list of two-dimensional pixel runs comprises:

a computer executable sub-module for merging pixel runs having identical x-coordinates and adjacent y-coordinates to create two-dimensional pixel runs; and

a computer executable sub-module for removing the pixel runs merged with another pixel run from the list of two-dimensional pixel runs.

14. The system of claim 12, further comprising a computer executable module for repairing binary large objects split by pixel removal during line recognition.

15. The system of claim 9, further comprising a computer executable module for defining the image-specific parameters.

16. The system of claim 9, wherein the raster image comprises a wiring diagram in raster format.

17. A computer-readable medium interpretable by a computer, the computer-readable medium comprising:

instructions for causing the computer to recognize text within a raster image by using optical character recognition and a character set associated with the raster image, the raster image comprising a network drawing in raster format;

instructions for causing the computer to extract the recognized text to produce a text-only raster image and a text-stripped raster image;

instructions for causing the computer to recognize graphic objects within the text-stripped raster image by using pattern recognition and image-specific parameters associated with the raster image,

instructions for causing the computer to use vector graphical primitives corresponding to the recognized graphic objects to produce a text-stripped vector image; and

instructions for causing the computer to add vector text elements corresponding to the extracted text into the text-stripped vector image to produce a vector image substantially identical in appearance to the raster image.

18. The computer-readable medium of claim 17, further comprising instructions for causing the computer to recognize less ambiguous graphic objects before recognizing more ambiguous graphic objects.

19. The computer-readable medium of claim 17, further comprising instructions for causing the computer to smooth noise while recognizing graphic objects within the text-stripped raster image.

20. The computer-readable medium of claim 17, wherein the instructions for causing the computer to recognize graphic objects within the text-stripped raster image further comprises:

instructions for causing the computer to build a list of two-dimensional pixel runs;

instructions for causing the computer to recognize lines from the list of two-dimensional pixel runs;

instructions for causing the computer to remove from the list of two-dimensional pixel runs the pixel runs recognized as lines;

instructions for causing the computer to recognizing binary large objects from the list of two-dimensional pixel runs; and

instructions for causing the computer to recognizing graphic objects from the recognized binary large objects by matching each binary large object with its corresponding vector graphical primitive.

21. The computer-readable medium of claim 20, wherein the instructions for causing the computer to build a list of two-dimensional pixel runs further comprises:

instructions for causing the computer to merge pixel runs having identical x-coordinates and adjacent y-coordinates to create two-dimensional pixel runs; and

instructions for causing the computer to remove the pixel runs merged with another pixel run from the list of two-dimensional pixel runs.

22. The computer-readable medium of claim 20, further comprising instructions for causing the computer to repair binary large objects split by pixel removal during line recognition.

23. The computer-readable medium of claim 17, wherein the raster image comprises a wiring diagram in raster format.