Method and apparatus for acquiring digital maps

• US 5,596,494 A
• Filed: 11/14/1994
• Issued: 01/21/1997
• Est. Priority Date: 11/14/1994
• Status: Expired due to Fees

• Current Assignee: Eotek, Inc.
• Original Assignee: Eotek, Inc.
• Inventors: Kuo, Shihjong
• Primary Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US08/338,423
• Time in Patent Office: 799 Days
• Field of Search: 364/420, 364/449, 342/357, 342/457, 348/117, 348/144-147
• US Class Current: 702/2
• CPC Class Codes: G01C 11/02 Picture taking arrangements specially adapted for photogrammetry or photographic surveying, e.g. controlling overlapping of pictures
• CPC Class Codes: G09B 29/106 using electronic means

Abstract

A method and an apparatus are disclosed that, when used in an airborne environment, acquire spatial imagery, that are instantaneous pictures of one or more terrestrial scenes, and the absolute geophysical coordinates (Latitude and Longitude) of ground objects simultaneously. Any number of series of terrestrial images and the absolute geophysical coordinate information are recorded digitally. The absolute geophysical coordinate information is displayed in real-time. The terrestrial imagery and the absolute geophysical coordinate coordinates are displayed and queried in near real-time. Thus, a new type of digital maps, comprising a two-dimensional terrestrial image and the absolute geophysical coordinates of any terrestrial objects in the image, is obtained using solely digitally-recorded spatial data on an original, unprocessed mission medium, or any secondary media. Near real-time images and accurate longitude and latitude coordinates can be displayed and queried before the aircraft lands.

Claims

1. A method of acquiring at least one instantaneous image of a terrestrial scene from a vehicle moving at a substantial distance above the ground and an associated set of absolute geophysical coordinates of terrestrial objects in said instantaneous picture, comprising the steps of:

a. using a set of devices associated with a frame imaging device to measure at least one set of angles relating an "x" axis, a "y" axis, a "z" axis of an image coordinate system with respect to a set of three world axes that include a forward flight axis, a cross-track axis, and a vertical axis, and tagging them with a first time mark for each set of angles;

b. using a positioning device associated with the moving vehicle to obtain at least one set of absolute geophysical coordinates and velocity of said frame imaging device, and tagging them with a second time mark or each set of coordinates;

c initiating an exposure of said frame imaging device, producing an instantaneous image, and tagging said exposure with a third time mark;

d. collecting said instantaneous image from said frame imaging device, said sets of angles, said sets of absolute geophysical coordinates and velocity, and a set of said time marks; and

e. calculating a set of absolute geophysical coordinates of terrestrial objects by means of formulas relating a spatial orientation relationship between said frame imaging device and said terrestrial objects.

2. The method of claim 1, wherein there is further included the step of:

simultaneously recording said instantaneous image and at least one of

said sets of angles, said sets of absolute geophysical coordinates and velocity, and a set of said time marks; and

said calculated set of absolute geophysical coordinates of terrestrial objects from step "e".

3. The method of claim 1, wherein in step "a" the step of using includes:

positioning said frame imaging device in the moving vehicle to direct it toward said terrestrial scene.

4. The method of claim 1, wherein in step "a" the step of using includes:

attaching said set of devices to said frame imaging devices.

5. The method of claim 1, wherein in step "b" the step of using includes:

attaching said positioning device to said moving vehicle.

6. The method of claim 1, wherein there is further included the step of:

acquiring the terrestrial image and the absolute geophysical coordinates simultaneously.

7. The method of claim 1, wherein there is further included the step of:

displaying the absolute geophysical coordinates of the center of the image and the image boundaries on a console immediately as the image is acquired.

8. The method of claim 1, wherein there is further included the step of:

recording said terrestrial image and said absolute geophysical coordinate information using digital means.

9. The method of claim 8, wherein the step of recording said terrestrial image and said absolute geophysical coordinate information using digital means further includes the step of:

recording said image and said information while said frame imaging device is above the ground and airborne.

10. The method of claim 1, wherein there is further included the step of:

using a CCD camera under computer control as the frame imaging device.

11. The method of claim 1, wherein there is further included the step of:

acquiring the absolute geophysical coordinates of the vehicle using a GPS unit as the position determination device.

12. The method of claim 1, wherein there is further included the step of:

acquiring the attitude information, including the roll angle, the pitch angle, and the drift angle of said frame imaging device at a time related to the time of initiating said exposure.

13. The method of claim 12, wherein there is further included the step of:

acquiring tinning information between the position and attitude determination events and the instant of each exposure.

14. The method of claim 1, wherein there is further included the step of:

calculating in real-time the absolute geophysical coordinates of said frame imaging device, and calculating in real-time in step "e" the absolute geophysical coordinates on a ground reference plane of at least one desired image feature after having corrected the geometric distortions arising from a non-zero roll angle, or a non-zero pitch angle, or a non-zero drift angle.

15. The method of claim 1, wherein there is further included the step of:

displaying said absolute geophysical coordinates of said frame imaging device and the terrestrial objects in the captured image.

16. The method of claim 1, wherein the vehicle is an airborne vehicle and wherein there is further included the step of:

transferring the image data, the airborne vehicle position information, the attitude information of the frame imaging device, and the timing information into a digital recording device located on said vehicle.

17. The method of claim 16, wherein there is further included the step of:

retrieving data from a payload medium from the vehicle for displaying images and querying the absolute geophysical coordinates of images features while airborne or shortly thereafter.

18. The method of claim 16, wherein there is further included the step of:

utilizing a digital recording media which is readily usable in desktop computer use.

19. The method of claim 1, wherein the vehicle is airborne and wherein there is further included the step of:

displaying the absolute geophysical coordinates of some terrestrial features in said image while the vehicle is airborne, with the exact ground coordinate of said features, including the four corners of each image, is displayed in real-time, wherein successful acquisition of the imagery over a target area can be confirmed in real-time.

20. The method of claim 19, wherein there is further included the step of:

displaying said absolute geophysical coordinates of said terrestrial features in said image while the image is being taken.

21. An apparatus for acquiring digital mapping information on an airborne environment comprising:

a. a frame imaging device mounted in a vehicle which moves above the ground a substantial distance;

b. a plurality of angle measuring devices attached to said frame imaging device for measuring a plurality of sets of angular orientations of a set of three world axes, a forward flight axis, a cross-track axis, a vertical axis, with respect to an "x" axis, a "y" axis, a "z" axis of an image coordinate system, and tagged with a first time mark;

c. a positioning device attached to said moving vehicle for obtaining a plurality of sets of absolute geophysical coordinates and velocity of said frame imaging device and tagged with a second time mark;

d. first processor means associated with said frame imaging device for initiating an exposure of said frame imaging device, tagging said exposure with a third time mark, and collecting data from said frame imaging device, said angle measuring devices, and said positioning device, including the set of said time marks; and

e. second processor means associated with said first processor means for manipulating said data collected from said frame imaging device, said angle measuring devices, said positioning device, and said set of time marks, in accordance to at least one formula relating a spatial orientation relationship between said frame imaging device and a terrestrial object to obtain a set of absolute geophysical coordinates of said terrestrial object.

22. A method of displaying and querying pictorial images and map information of a plurality of terrestrial objects, comprising the steps of:

a. using a data medium of contents containing at least one instantaneous pictorial images, at least one set of angles relating a spatial orientation relationships of an "x" axis, a "y" axis, and a "z" axis of an image coordinate system positioned at an exposure station, from which said pictorial images(s) were exposed, to a set of three world axes which include a forward flight axis, a cross-track axis and a vertical axis, a plurality of sets of absolute geophysical coordinates and velocity of said exposure stations, a plurality of sets of time marks which distinguish the occurrences of exposures of said pictorial images, measurement of said sets of angles, and measurement of said sets of absolute geophysical coordinates and velocity;

b. using a data medium having recorded data containing said contents of step "a" while said contents were acquired on a vehicle moving above ground;

c. retrieving said recorded data from said data medium of step "b";

d. displaying said pictorial images on a display console as a discrete two dimensional matrix array of pixels of varying brightness;

e. providing a means to indicate a pixel of interest and alter the location of said pixel of interest; and

f. applying a set of formulas relating a spatial orientation relationship between said pixel of interest and a terrestrial object in said pictorial images obtaining and displaying a set of absolute geophysical coordinates of a terrestrial object indicated by said pixel of interest.

23. A data acquisition, information display and querying apparatus for acquiring instantaneous pictures of a terrestrial scene and a set of absolute geophysical coordinates of terrestrial objects in said picture simultaneously, displaying said pictures on a display console as a discrete two dimensional matrix array of pixels of varying brightness, querying from said pictures of a terrestrial object at which location a set of absolute geophysical coordinates is of interest, comprising:

a. a frame imaging device mounted in a moving vehicle above the ground;

b. a plurality of angle measuring devices attached to said frame imaging device for measuring a plurality of sets of angular orientations of a set of three world axes, a forward flight axis, a cross-track axis, a vertical axis, with respect to an "x" axis, a "y" axis, a "z" axis of an image coordinate system and tagged with a first time mark;

c. a positioning device attached to said moving vehicle for obtaining a plurality of sets of absolute geophysical coordinates and velocity of said frame imaging device and tagged with a second time mark;

d. first processor means associated with said exposure imaging device for initiating an exposure of said frame imaging device, tagging said exposure with a third time mark, collecting data from said frame imaging device, said angle measuring devices, and said positioning device, as well as the data set of said fist, second and third time marks;

e. second processor means associated with said first processor means for manipulating said data collected from said frame imaging device, said angle measuring devices, said positioning device, and said set of time marks, in accordance to at least one formula relating a spatial orientation relationship between said frame imaging device and a terrestrial object to obtain a set of absolute geophysical coordinates of said terrestrial object;

f. a data medium onto which data from said frame imaging device, said angle measuring devices, said positioning device, and said set of time marks are recorded;

h. third processor means associated with said data medium for retrieving said written data from said data medium, displaying a pictorial image on a display console as a discrete, two dimensional matrix array of pixels of varying brightness, providing a means to indicate a pixel of interest, and providing a means to alter said pixel of interest; and

g. fourth processor means associated with and utilizing said second processor means to obtain a set of absolute geophysical coordinates of a terrestrial object indicated by said pixel of interest, and displaying said set of absolute geophysical coordinates of a terrestrial object indicated by said pixel of interest.