Systems and methods of capturing large area images in detail including cascaded cameras and/or calibration features

• US 8,497,905 B2
• Filed: 09/23/2009
• Issued: 07/30/2013
• Est. Priority Date: 04/11/2008
• Status: Active Grant

• Current Assignee: Nearmap Australia Pty., Ltd.
• Original Assignee: NearMap Pty Ltd.
• Inventors: Nixon, Stuart William
• Primary Examiner(s): Ustaris, Joseph
• Assistant Examiner(s): MCINNISH, KEVIN K
• Application Number:
  US12/565,232
• Publication Number:
  US 20100013927A1
• Time in Patent Office: 1,406 Days
• Field of Search: None
• US Class Current: 348/143
• CPC Class Codes: B64D 47/08 Arrangements of cameras
• CPC Class Codes: B64G 1/1021 Earth observation satellites
• CPC Class Codes: B64G 1/1028 using optical means for mapping, surveying or detection, e.g. of intelligence
• CPC Class Codes: B64G 1/1085 Swarms and constellations
• CPC Class Codes: B64U 20/87 Mounting of imaging devices, e.g. mounting of gimbals
• CPC Class Codes: G01C 11/06 by comparison of two or more pictures of the same area
• CPC Class Codes: H04N 25/41 Extracting pixel data from a plurality of image sensors simultaneously picking up an image, e.g. for increasing the field of view by combining the outputs of a plurality of sensors

Abstract

A method and system are presented in which images are captured from overview and detail imaging devices such that overview images are created with a first degree of redundancy, and detail images are captured with less overlap and a second degree of redundancy.

Claims

1. An image capture system comprising:

a first image capture subsystem comprising a first imaging device configured to capture, at a first instance in time, at least one overview image of an overview area, the at least one overview image having a first resolution; and

a second image capture subsystem comprising a second imaging device configured to capture, substantially concurrent with the first instance in time, at least one detail image of at least a portion of the overview area, the at least one detail image having a second resolution higher than the first resolution, the first and second image capture subsystems being configured such that a plurality of overview images overlap to result in an overview redundancy of overview image elements appearing in the plurality of overview images and a plurality of detail images overlap to result in a detail redundancy of detail image elements appearing in the plurality of detail images,

wherein a percentage overlap among the plurality of overview images is greater than a percentage overlap among the plurality of detail images,

wherein after capture of the plurality of overview images and the plurality of detail images, interior and exterior orientations of the detail images are determined based on a bundle adjustment process using the plurality of overview images and the plurality of detail images in order to determine 3-dimensional coordinates of detail image elements,

wherein the overview redundancy is greater than 10 images and the detail redundancy is less than or equal to 10 images,

wherein an area of at least one overlapping overview portion between a first and second overview image is greater than or equal to 50% of an area of one of the first and second overview images, and

wherein an area of at least one overlapping detail portion of a first and second detail image is less than or equal to 20% of an area of one of the first and second detail images.

2. The image capture system of claim 1, wherein the first image capture subsystem includes a plurality of imaging devices arranged to capture the plurality of overview images.

3. The image capture system of claim 2, wherein the plurality of imaging devices is arranged to capture the plurality of overview images substantially simultaneously.

4. The image capture system of claim 2, wherein the plurality of imaging devices are adjacently arranged to capture the plurality of overview images.

5. The image capture system of claim 1, wherein the first and second image capture subsystems are located proximate to each other.

6. The image capture system of claim 1, wherein the overview redundancy represents a degree to which the overview image elements appear in multiple overview images, and

the detail redundancy represents a degree to which the detail image elements appear in multiple detail images.

7. The image capture system of claim 6, wherein the overview image elements and the detail image elements include one or more identifiable features, areas or markings corresponding to the overview area captured in the at least one overview image and the at least one detail image.

31. The image capture system of claim 1, wherein the first imaging device of the first image capture subsystem has a first focal length, and the second image capture subsystem includes at least two second imaging devices, each having a second focal length different from the first focal length.

33. The image capture system of claim 31, wherein a photomap is generated from the plurality of detail images based on the determined interior and exterior orientations.

34. The image capture system according to claim 1, wherein the first resolution represents a minimum object size that is distinguishable in the at least one overview image, and the second resolution represents a minimum object size that is distinguishable in the at least one detail image.

8. An image capture system comprising:

a first image capture subsystem comprising a first imaging device configured to capture, at a first instance in time, at least one overview image of an overview area at a first ground resolution; and

a second image capture subsystem comprising a second imaging device configured to capture, substantially concurrent with the first instance in time, at least one detail image of at least a portion of the overview area, the at least one detail image being at a second ground resolution that is higher than the first ground resolution, wherein

the at least one overview image overlaps with previously captured overview images by a first overlap,

the at least one detail image overlaps previously captured detail images by a second overlap, a percentage overlap of the first overlap being greater than a percentage overlap of the second overlap,

after capture of a plurality of overview images and a plurality of detail images, interior and exterior orientations of the detail images are determined based on a bundle adjustment process using the plurality of overview images and the plurality of detail images in order to determine 3-dimensional coordinates of detail image elements,

wherein the first overlap corresponds to a first image redundancy of greater than 10 images and the second overlap corresponds to a second image redundancy of less than or equal to 10 images,

wherein an area of at least one overlapping overview portion between a first and second overview image is greater than or equal to 50% of an area of one of the first and second overview images, and

wherein an area of at least one overlapping detail portion of a first and second detail image is less than or equal to 20% of an area of one of the first and second detail images.

9. The image capture system of claim 8, wherein the first and second image capture subsystems are configured such that a plurality of overview images results in a redundancy of overview image elements among the plurality of overview images and a plurality of detail images results in a redundancy of detail image elements among the plurality of detail images.

10. The image capture system of claim 8, wherein the first image capture subsystem includes a plurality of imaging devices arranged to capture a plurality of overview images of one or more overview areas.

11. The image capture system of claim 10, wherein the plurality of imaging devices is arranged to capture the plurality of overview images substantially simultaneously.

12. The image capture system of claim 10, wherein the plurality of imaging devices are adjacently arranged to capture the plurality of overview images.

13. The image capture system of claim 10, wherein the plurality of imaging devices are cascaded to capture the plurality of overview images.

14. The image capture system of claim 8, wherein the second image capture subsystem includes a plurality of imaging devices arranged to capture a plurality of detail images of one or more detail areas.

15. The image capture system of claim 14, wherein the plurality of imaging devices is arranged to capture the plurality of detail images substantially simultaneously.

16. The image capture system of claim 14, wherein the plurality of imaging devices are adjacently arranged to capture the plurality of detail images.

17. The image capture system of claim 14, wherein the plurality of imaging devices are cascaded to capture the plurality of detail images.

18. The image capture system of claim 8, wherein the first and second image capture subsystems are located proximate to each other.

19. The image capture system of claim 8, wherein the first and second image capture subsystems are mounted in or on an aircraft.

20. The image capture system of claim 19, wherein the first and second image capture subsystems are arranged within a housing on the aircraft.

21. The image capture system of claim 20, wherein the housing is removably attached to the aircraft.

22. The system of claim 8, wherein the second imaging device is a digital camera.

23. The system of claim 8, wherein the second imaging device is a CMOS sensor.

24. The system of claim 8, wherein the second image capture subsystem includes a plurality of second imaging devices arranged as a push broom sensor.

25. The system of claim 8, wherein the second imaging device is a whisk broom sensor.

26. The system of claim 8, wherein the overview images are stored within the first imaging device of the first image capture subsystem without transmitting the overview images to a storage device outside the first imaging device.

27. The system of claim 8, wherein the detail images are stored within the second imaging device of the second image capture subsystem without transmitting the detail images to a storage device outside the second imaging device.

32. The image capture system of claim 19, wherein the first and second overlaps include a forward overlap that is determined by a rate of image capture, and a side overlap that is determined by a flight path of the aircraft.

28. A method of capturing images, the method comprising:

(a) capturing, by a first image capture subsystem, a first overview image of an overview area, the first overview image being at a first ground resolution; and

(b) capturing, by a second image capture subsystem, substantially simultaneously with the capture of the first overview image, a first detail image of at least a portion of the overview area, the first detail image being at a second ground resolution that is higher than the first ground resolution;

(c) translating the first and second image capture subsystems along a first axis;

(d) capturing, by the first image capture subsystem, a second overview image of a second overview area at the first ground resolution, wherein the first and second overview images have at least one overlapping overview portion with respect to each other;

(e) capturing, by the second image capture subsystem, a second detail image at a second ground resolution, wherein the first and second detail images have at least one overlapping detail portion with respect to each other with a percentage overlap that is substantially smaller than a percentage overlap of the overlapping overview portion of the first and second overview images; and

(f) after capturing of the first and second overview images and the first and second detail images, determining interior and exterior orientations of the first and second detail images based on a bundle adjustment process using the first and second overview images and the first and second detail images in order to determine 3-dimensional coordinates of detail image elements,

wherein at least one of the overlapping overview portion and the overlapping detail portion results in an overview redundancy with respect to the first and second overview images and a detail redundancy with respect to the first and second detail images,

wherein the overview redundancy is greater than 10 images and wherein the detail redundancy is less than or equal to 10 images,

wherein an area of the at least one overlapping overview portion along the first axis is greater than or equal to 50% of an area of one of the first and second overview images, and

wherein an area of the at least one overlapping detail portion along the first axis is less than or equal to 20% of an area of one of the first and second detail images.

29. The method of claim 28, wherein the overview redundancy represents a degree to which overview image elements appear in multiple overview images, and

the detail redundancy represents a degree to which detail image elements appear in multiple detail images.

30. The method of claim 29, wherein the overview image elements and the detail image elements include one or more identifiable features, areas or markings corresponding to the overview area captured in at least one of the first overview image and the second overview image and at least one of the first detail image and the second detail image.