Method and apparatus for enhancing a digital elevation model (DEM) for topographical modeling

• US 7,142,984 B2
• Filed: 02/08/2005
• Issued: 11/28/2006
• Est. Priority Date: 02/08/2005
• Status: Expired due to Fees

• Current Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: Rahmes, Mark, Karp, John, Smith, Anthony, Connetti, Jr., Stephen
• Primary Examiner(s): MCELHENY JR, DONALD E
• Application Number:
  US11/053,495
• Publication Number:
  US 20060176213A1
• Time in Patent Office: 658 Days
• Field of Search: 702/5, 702/2, 382/113
• US Class Current: 702/5
• CPC Class Codes: G01C 11/00 Photogrammetry or videogrammetry, e.g. stereogrammetry; Photographic surveying
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G06T 17/05 Geographic models
• CPC Class Codes: G06V 10/30 Noise filtering

Abstract

A computer implemented method is for processing an original digital elevation model (DEM) including data for terrain and a plurality of objects thereon. The method includes generating a lower-resolution DEM from the original DEM, and generating an objects-only DEM based upon a comparison of the lower-resolution DEM and the original DEM. The method further includes reducing noise in the objects-only DEM.

Claims

1. A computer implemented method for processing an original digital elevation model (DEM) including data for terrain and a plurality of objects thereon, the method comprising:

generating a lower-resolution DEM from the original DEM;

generating an objects-only DEM based upon a comparison of the lower-resolution DEM and the original DEM; and

reducing noise in the objects-only DEM.

2. A computer implemented method according to claim 1 wherein reducing noise in the objects-only DEM comprises:

identifying nulls in the objects-only DEM based upon a first window size;

expanding the nulls identified in the objects-only DEM; and

filling in the expanded nulls in the objects-only DEM to generate a first refined objects-only DEM.

3. A computer implemented method according to claim 2 further comprising:

identifying nulls in the first refined objects-only DEM based upon the first window size;

expanding the nulls identified in the first refined objects-only DEM; and

filling in the expanded nulls in the first refined objects-only DEM to generate a second refined objects-only DEM.

4. A computer implemented method according to claim 3 further comprising generating a noise-only DEM based upon a comparison between the first refined objects-only DEM and the second refined objects-only DEM.

5. A computer implemented method according to claim 4 further comprising subtracting the noise-only DEM from the second refined objects-only DEM for generating a final refined objects-only DEM.

6. A computer implemented method for processing a digital elevation model (DEM) including data for a terrain and a plurality of objects on the terrain, the method comprising:

generating a lower-resolution DEM from the original DEM;

identifying nulls in the lower-resolution DEM based upon a first window size, and filling in the nulls;

generating an objects-only DEM based upon a comparison of the lower-resolution DEM with the filled-in nulls and the original DEM;

generating an original DEM without the objects based upon a comparison between the objects-only DEM and the original DEM;

identifying nulls in the original DEM without the objects based upon the first window size, and expanding the nulls;

generating a lower-resolution DEM without the objects from the original DEM without the objects;

identifying nulls in the lower-resolution DEM without the objects based upon the first window size, and filling in the nulls for generating a terrain-only DEM; and

generating a refined objects-only DEM based upon a comparison of the terrain-only DEM with the original DEM.

7. A computer implemented method according to claim 6 further comprising:

generating a refined DEM without the objects based upon a comparison between the refined objects-only DEM and the original DEM;

generating a lower-resolution DEM without the objects from the refined DEM without the objects; and

identifying nulls in the lower-resolution DEM without the objects based upon the first window size, and filling in the nulls for generating a refined terrain-only DEM.

8. A computer implemented method according to claim 7 further comprising generating a final refined objects-only DEM based upon a comparison of the refined terrain-only. DEM with the original DEM.

9. A computer-readable medium having stored thereon a data structure for processing a digital elevation model (DEM) including data for terrain and a plurality of objects thereon, the computer-readable medium comprising:

a first data field containing data for generating a lower-resolution DEM from the original DEM;

a second data field containing data for generating an objects-only DEM based upon a comparison of the lower-resolution DEM and the original DEM; and

a third data field containing data for reducing noise in the objects-only DEM.

10. A computer-readable medium according to claim 9 wherein the third data field for reducing noise in the objects-only DEM comprises:

a fourth data field containing data for identifying nulls in the objects-only DEM based upon a first window size;

a fifth data field containing data for expanding the nulls identified in the objects-only DEM; and

a sixth data field containing data for filling in the expanded nulls in the objects-only DEM to generate a first refined objects-only DEM.

11. A computer-readable medium according to claim 10 further comprising:

a seventh data field containing data for identifying nulls in the first refined objects-only DEM based upon the first window size;

an eighth data field containing data for expanding the nulls identified in the first refined objects-only DEM; and

a ninth data field containing data for filling in the expanded nulls in the first refined objects-only DEM to generate a second refined objects-only DEM.

12. A computer-readable medium according to claim 11 further comprising a tenth data field containing data for generating a noise-only DEM based upon a comparison between the first refined objects-only DEM and the second refined objects-only DEM.

13. A computer-readable medium according to claim 12 further comprising an eleventh data field containing data for subtracting the noise-only DEM from the second refined objects-only DEM for generating a final refined objects-only DEM.

14. A computer-readable medium for processing a digital elevation model (DEM) including data for a terrain and a plurality of objects on the terrain, the computer-readable medium comprising:

a first data field containing data for generating a lower-resolution DEM from the original DEM;

a second data field containing data for identifying nulls in the lower-resolution DEM based upon a first window size, and filling in the nulls;

a third data field containing data for generating an objects-only DEM based upon a comparison of the lower-resolution DEM with the filled in nulls and the original DEM;

a fourth data field containing data for generating an original DEM without the objects based upon a comparison between the objects-only DEM and the original DEM;

a fifth data field containing data for identifying nulls in the original DEM without the objects based upon the first window size, and expanding the nulls;

a sixth data field containing data for generating a lower-resolution DEM without the objects from the original DEM without the objects;

a seventh data field containing data for identifying nulls in the lower-resolution DEM without the objects based upon the first window size, and filling in the nulls for generating a terrain-only DEM; and

an eighth data field containing data for generating a refined objects-only DEM based upon a comparison of the terrain-only DEM with the original DEM.

15. A computer-readable medium according to claim 14 further comprising:

a ninth data field containing data for generating a refined DEM without the objects based upon a comparison between the refined objects-only DEM and the original DEM;

a tenth data field containing data for generating a lower-resolution DEM without the objects from the refined DEM without the objects; and

an eleventh data field containing data for identifying nulls in the lower-resolution DEM without the objects based upon the first window size, and filling in the nulls for generating a refined terrain-only DEM.

16. A computer-readable medium according to claim 15 further comprising a twelfth data field containing data for generating a final refined objects-only DEM based upon a comparison of the refined terrain-only DEM with the original DEM.

17. A computer system for topographical modeling comprising:

a processor for processing an original digital elevation model (DEM) including data for terrain and a plurality of objects thereon, the processing comprising

generating a lower-resolution DEM from the original DEM,

generating an objects-only DEM based upon a comparison of the lower-resolution DEM and the original DEM, and

reducing noise in the objects-only DEM; and

a display coupled to said processor for displaying a topographical model based upon the processing.

18. A computer system according to claim 17 wherein said processor for reducing noise in the objects-only DEM performs the following:

identifies nulls in the objects-only DEM based upon a first window size;

expands the nulls identified in the objects-only DEM; and

fills in the expanded nulls in the objects-only DEM to generate a first refined objects-only DEM.

19. A computer system according to claim 18 wherein said processor further performs the following:

identifies nulls in the first refined objects-only DEM based upon the first window size;

expands the nulls identified in the first refined objects-only DEM; and

fills in the expanded nulls in the first refined objects-only DEM to generate a second refined objects-only DEM.

20. A computer system according to claim 19 wherein said processor generates a noise-only DEM based upon a comparison between the first refined objects-only DEM and the second refined objects-only DEM.

21. A computer system according to claim 20 wherein said processor subtracts the noise-only DEM from the second refined objects-only DEM for generating a final refined objects-only;

and wherein said display displays the topographical model based upon the final refined objects-only.

22. A computer system for topographical modeling comprising:

a processor for processing an original digital elevation model (DEM) including data for terrain and a plurality of objects thereon, the processing comprising

generating a lower-resolution DEM from the original DEM,

identifying nulls in the lower-resolution DEM based upon a first window size, and filling in the nulls,

generating an objects-only DEM based upon a comparison of the lower-resolution DEM with the filled-in nulls and the original DEM,

generating an original DEM without the objects based upon a comparison between the objects-only DEM and the original DEM,

identifying nulls in the original DEM without the objects based upon the first window size, and expanding the nulls,

generating a lower-resolution DEM without the objects from the original DEM without the objects,

identifying nulls in the lower-resolution DEM without the objects based upon the first window size, and filling in the nulls for generating a terrain-only DEM, and

generating a refined objects-only DEM based upon a comparison of the terrain-only DEM with the original DEM; and

a display coupled to said processor for displaying a topographical model based upon the processing.

23. A computer system according to claim 22 wherein said processor further performs the following:

generating a refined DEM without the objects based upon a comparison between the refined objects-only DEM and the original DEM;

generating a lower-resolution DEM without the objects from the refined DEM without the objects; and

identifying nulls in the lower-resolution DEM without the objects based upon the first window size, and filling in the nulls for generating a refined terrain-only DEM.

24. A computer system according to claim 23 wherein said processor further generates a final refined objects-only DEM based upon a comparison of the refined terrain-only DEM with the original DEM.