Digital map generator and display system

• US 4,970,682 A
• Filed: 03/15/1988
• Issued: 11/13/1990
• Est. Priority Date: 01/13/1981
• Status: Expired due to Term

• Current Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: Basta, Wayne E., Beckwith, Paul B. Jr., Chan, Luen C., Bascle, Kent P.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Sotomayor, John B.
• Application Number:
  US07/168,437
• Time in Patent Office: 973 Days
• Field of Search: 342/176, 342/179, 364/900, 364/522, 434/2, 340/727, 340/728, 340/747
• US Class Current: 1/1
• CPC Class Codes: G06T 15/005 General purpose rendering architectures
• CPC Class Codes: G06T 15/10 Geometric effects
• CPC Class Codes: G09B 9/24 including display or recording of simulated flight path
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99942 Manipulating data structure, e.g. compression, compaction, compilation

Abstract

A digital information storage and read-out system in which digital elevation and cultural terrain data is read from a magnetic tape in compressed form into an intermediate memory which operates as a speed buffer memory. The data in the intermediate memory is read out to a reconstruction processor in which the compressed data is reconstructed and applied to a scene memory. A nagivation computer determines the instantaneous position of a vehicle with respect to the terrain and controls the reading of data into the scene memory in blocks with the vehicle position occupying a center of scene location. In order to provide a heading up display of the terrain, the data in the scene memory is read out at an angle to its north-up storage orientation and interlaced scanning of pixel data in the scene memory improves resolution and enhances line display. The data read out of the scene memory controls the generation of video control signals to effect a display of the elevation and cultural data as a moving map related to the vehicle position.

Claims

1. For use with a digital data base representative of at least a two dimensional pattern of information, an apparatus for controllably processing data from the digital data base, comprising:

memory means for storing, in addressable memory locations thereof, at least a portion of the digital data representing at least a selected part of the pattern such that, as stored in said memory, said portion of digital data has a reference orientation;

control means for transferring data from the digital data base to said memory means; and

read-out control means for controllably accessing said addressable memory locations of said memory means so as to cause data representing said pattern to be read out therefrom at an effective orientation which is rotated with respect to said reference orientation, so that the resulting pattern has said rotated orientation, and wherein said control means includes intermediate memory means for storing at least a portion of the data transferred thereto from said digital data base prior to application to said memory means, and wherein said addressable memory locations of said memory means comprises a plurality of memory storage segments, and wherein said control means includes memory management control means for transferring portions of the data representing selected parts of the pattern of information to first selected ones of said memory storage segments for storage therein and said read-out control means includes means for reading out at least a portion of the data from second selected ones of said memory storage segments to obtain the resulting read-out pattern, and wherein said memory management control means includes means for transferring data to said memory means in addressable segments which form a part of the pattern of information, including means for storing said segments in locations of said memory means which are not necessarily in correspondence with the pattern of information, and directory means for storing the correspondence between selected locations in said memory means and the position of each segment in the pattern.

2. An apparatus according to claim 1, wherein said memory management control means includes means for reloading selected ones of said segments of data stored in said memory means with new segments of data comprising part of the pattern of information.

3. An apparatus according to claim 2, wherein said memory management control means includes means for replacing, without regard to the relative location of said segments in the pattern of information, selected ones of said segments of data stored by said memory means in accordance with an anticipated change in a selected part of the pattern to be read out from said memory means.

4. An apparatus according to claim 1, wherein said digital data base is stored in a magnetic data storage system.

5. An apparatus according to claim 1, wherein the data base contains data which has been compressed in the discrete cosine transform domain.

6. An apparatus according to claim 5, further including reconstruction processor means for expanding the compressed data from the discrete cosine transform domain to the spatial domain prior to application to said memory means.

7. An apparatus according to claim 1, wherein said read-out control means includes means for reading out data from said memory means in alternately addressed, first and second interlaced fields.

8. An apparatus according to claim 7, wherein said second interlaced field is effectively diagonally offset from said first interlaced field.

9. An apparatus according to claim 8, wherein said memory means is effectively definable as a two dimensional array of storage locations and wherein each of said first and second interlaced fields comprises a field of addresses for accessing the array of storage locations in said memory means, and wherein said first and second interlaced fields are effectively offset from one another in mutually-orthogonal directions by a separation of one half the differential between adjacent storage locations.

10. An apparatus according to claim 1, wherein said apparatus is for use with a display device for displaying data contained within said digital data base and wherein said read out control means includes means for causing data read out from said memory means to be transferred to the display device and displayed thereby effectively in real time with the controllably accessing of said addressable memory locations of said memory means.

11. An apparatus according to claim 1, wherein the pattern of information is representative of a map of features of terrain, comprised of a matrix of data points, at respective ones of which features of said terrain are defined, and wherein said data base contains data which has been compressed in the transform domain through discrete cosine transform and differential pulse code modulation compression.

12. An apparatus according to claim 11, wherein said features of terrain includes elevation values for said terrain at locations thereof corresponding to said data points.

13. An apparatus according to claim 11, wherein said features of terrain includes cultural features at locations on said terrain associated with prescribed ones of said data points.

14. A digital information read-out system for use in generating a moving map of terrain data on a video display from a stored digital data base representing a predetermined area of terrain including at least elevation information, with data base including addressable data having a fixed orientation with respect to geographical areas in the terrain, comprising:

memory means for storing digital data representing at least a part of the predetermined area of terrain; and

transferring means for transferring segments of data from the stored digital data base into said memory means in selected locations which may, but need not necessarily, correspond to the locations of the segments of data in the predetermined area of terrain, and means for reading the data out of said memory means in accordance with the location of the data in the predetermined area of terrain rather than its location in said memory means.

15. A digital information read-out system as defined in claim 14, wherein said transferring means includes directory means for storing the correspondence between the location of each segment of data in the predetermined area of terrain and the location of that segment of data in said memory means.

16. A digital information read-out system as defined in claim 15, where said transferring means further comprises read-out control means for generating read-out addresses to be applied to said memory means for reading-out data from said memory means.

17. A digital information read-out system as defined in claim 16, wherein said read-out control means includes means for generating read-out addresses such that data out of said memory means is associated with prescribed locations of pixels of the video display.

18. A digital information read-out system as defined in claim 17, wherein said read-out control means includes means for generating a starting read-out address of a series of successive addresses for reading data out of said memory means such that the pixel associated therewith is located at a preselected location on the video display.

19. A digital information read-out system as defined in claim 16, wherein the digital data as stored in said memory means corresponds to the predetermined area of terrain having a fixed geographical orientation, and wherein said read-out control means includes means for generating said read-out addresses so that the digital data, when read out, has a geographical orientation which is rotated with respect to said fixed geographical orientation.

20. A digital information read-out system as defined in claim 19, wherein said rotated geographical orientation is defined with relation to the effective direction of simulation movement of a vehicle over the predetermined area of terrain.

21. A digital information read-out system as defined in claim 19, wherein said directory means is provided as part of said read-out control means and includes means for modifying said read-out addresses by converting at least a part of said addresses from virtual to absolute address form.

22. A digital information read-out system as defined in claim 18, wherein said read-out control means further includes means for reading out data from said memory means in first and second interleaved fields of scan addresses for accessing storage locations of said memory means.

23. A digital information read-out system as defined in claim 22, wherein said memory means is effectively definable as a two dimensional array of storage locations and wherein each of said first and second interlaced fields comprises a field of addresses for accessing the array of storage locations in said memory means, and wherein said first and second interlaced fields are effectively offset from one another in mutually-orthogonal directions by a separation of one-half the differential between adjacent storage locations.

24. A digital information read-out system as defined in claim 18, further including intermediate memory means for temporarily storing a portion of the data received from the stored digital data base prior to application to said memory means.

25. A digital information read-out system as defined in claim 24, wherein the digital data in the data base contains data which has been compressed in the discrete cosine transform domain, and further including reconstruction processor means for reconstructing said compressed data prior to its application to said memory means.

26. A digital information read-out system as defined in claim 25, wherein said reconstruction processor means is coupled between said intermediate memory means and said memory means.

27. A digital information read-out system as defined in claim 25, wherein the digital data base includes a magnetic tape system in which the digital data is stored on a magnetic tape.

28. A digital information read-out system as defined in claim 14, wherein the digital data also includes cultural information relating to the predetermined area of terrain, and further including cultural data processor means responsive to data stored in said memory means for generating display signals to display said cultural data.

29. A digital information read-out system as defined in claim 14, wherein said addressing means reads out data from said memory means which is then displayed on the video display in real time with the reading out of data from said memory means.

30. A digital information read-out system as defined in claim 14, wherein said pattern of information represents a map of features of terrain comprised of a matrix of data points for respective ones of which features of the terrain are defined and wherein the data base contains data which has been compressed in the transform domain through discrete cosine transform and differential pulse code modulation compression.

31. A digital information read-out system as defined in claim 30, wherein said features of terrain include elevation values for the terrain at locations thereof corresponding to said data points.

32. A digital information read-out system as defined in claim 31, wherein said features of terrain include cultural features at locations on the terrain associated with prescribed ones of said data points.

33. A digital information read-out system as defined in claim 30, wherein said data is data which has been compressed in a prescribed direction of data points of matrix through said discrete cosine transform.

34. A digital information read-out system as defined in claim 33, wherein data that has been compressed through said discrete cosine transform has been further compressed through differential pulse code modulation compression.

35. A digital information processing and display system, for use in generating a moving map display of cultural data comprising:

a video display including a plurality of pixels;

a system for reading, from a data base containing data which has been compressed in the discrete cosine transform domain and stored on magnetic tape, digital data representing pictorial information to be used for energizing the pixels of the video display;

an intermediate memory for temporarily storing blocks of digital data read by said reading system, said blocks of digital data representing discrete sections of said pictorial information;

a scene memory for storing selected ones of said blocks of digital data, representative of a subdivision of said pictorial information received from said intermediate memory;

processor means for reconstructing the compressed data from said intermediate memory to be applied to said scene memory;

reconstruction control means for controlling the transfer of digital data from said reading system to said intermediate memory and from said intermediate memory to said scene memory and including means for generating write addresses for writing said blocks of digital data into said scene memory with a known orientation such that, as stored in said scene memory, said digital data has said known orientation;

read-out means for generating read-out address signals to be applied to said scene memory so as to cause digital data to be read out therefrom and including means for causing the digital data to be read out from said scene memory with an orientation which is selectively rotated with respect to said orientation; and

display signal generating means for generating display control signals in response to the data read out of said scene memory, said display control signals being applied to said video display to energize said pixels of said video display and thereby display said pictorial information, and wherein said control means includes first addressing means for updating the contents of said intermediate memory by writing new ones of said blocks of data received from said reading system into said intermediate memory, and first directory means for storing the correspondence between the location of each of said blocks of data in said intermediate memory and the location of said block of data within said pictorial information.

36. A digital information processing and read-out system as defined in claim 35, wherein said control means includes second addressing means for writing new ones of said blocks of data received from said intermediate memory into locations in said scene memory, and wherein said read-out means includes second directory means for storing the correspondence between the location of each of said blocks of data in said scene memory and the location of said block of data within said pictorial information.

37. A digital information storage and read-out system for use in simulating, on a visual display, movement of a vehicle over terrain represented by digital data stored in a digital data base as data to be employed for energizing pixels of the visual display and addressable in relation to a coordinate position of the data in the terrain, comprising:

a scene memory for storing selected blocks of digital data representing at least that portion of the terrain over which the vehicle is moving, with said blocks of digital data representing subdivisions of terrain being related to each other and stored in said scene memory with a known orientation;

control means for supplying the data from the data base to said scene memory; and

read-out control means for addressing individual storage locations in said scene memory to read out data relating to that portion of the terrain to be displayed, including means responsive to navigational position and heading information of the vehicle for selectively causing data to be read out from said scene memory with a geographical orientation which is rotated with respect to said know orientation, and wherein said control means includes an intermediate memory as a buffer for data read from the digital data base prior to storage in said scene memory, and wherein said control means includes means for updating the contents of said intermediate memory as the navigational position of said vehicle changes by writing new ones of said blocks of data into locations where not currently useful ones of said blocks of data are stored without regard to the positional relationship of new ones of said blocks of data to the other blocks of data in said intermediate memory, and further including directory means for storing the correspondence between the location of each of said blocks of data in said intermediate memory and the location of the corresponding one of said blocks of data in said terrain, and further including means, responsive to said directory means, for reading said blocks of data from said intermediate memory in accordance with the location of the data in the terrain rather than its location in said intermediate memory means.

38. For use with a digital data base representative of at least a three dimensional pattern of information having a reference orientation, a method for controlling processing data of the digital data base, comprising the steps of:

storing, in addressable memory locations of a memory, at least a portion of the digital data representing at least a selected part of the pattern such that, as stored in said addressable memory locations, said digital data has a known relationship to the reference orientation;

transferring data form the digital data base to said memory; and

controllably accessing said addressable memory locations of said memory so as to cause data to be read out therefrom with an effective orientation which is rotated with respect to said reference orientation, such that the resulting pattern of information has an effective orientation which is rotated with respect to said reference orientation, and wherein the steps of reading out and processing the data corresponding to the resulting pattern of information from said addressable locations is accomplished in real time and, wherein said addressable memory locations of said memory means comprise a plurality of memory storage segments, and wherein said data transferring step includes transferring portions of the data representing selected parts of the pattern of information to first selected ones of said memory storage segments for storage therein and reading out at least a portion of the data from second selected ones of said memory storage segments to obtain said resulting read-out pattern, and wherein said data transferring step includes transferring data to said memory in addressable segments which form a part of the pattern of information, including storing said segments in location of said memory which are not necessarily in correspondence with the pattern of information, and storing the correspondence between selected locations in said memory and the position of each segment in the pattern.