Efficient airborne oblique image collection

• US 10,424,105 B2
• Filed: 03/11/2016
• Issued: 09/24/2019
• Est. Priority Date: 03/11/2015
• Status: Active Grant

• Current Assignee: James Kain, James Summerville
• Original Assignee: James Kain, James Summerville
• Inventors: Summerville, James, Kain, James
• Primary Examiner(s): Cass, Jean Paul
• Application Number:
  US15/067,609
• Publication Number:
  US 20180053336A1
• Time in Patent Office: 1,292 Days
• 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: G01C 21/3826 Terrain data
• CPC Class Codes: G01C 21/3852 Data derived from aerial or satellite images
• CPC Class Codes: G01S 5/0009 Transmission of position information to remote stations involving assistance data G01S5/0236
• CPC Class Codes: G03B 15/006 Apparatus mounted on flying objects
• CPC Class Codes: G06T 15/005 General purpose rendering architectures
• CPC Class Codes: G06T 15/04 Texture mapping
• CPC Class Codes: G06T 15/205 Image-based rendering
• CPC Class Codes: G06T 17/05 Geographic models
• CPC Class Codes: G08G 5/0021 located in the aircraft
• CPC Class Codes: G08G 5/0047 Navigation or guidance aids for a single aircraft details of equipment G08G5/0017
• CPC Class Codes: G08G 5/0052 for cruising combined instruments indicating more than one navigational value G01C23/00

Abstract

A system and method for airborne oblique image collection provides a dense diversity of view aspects of a subtended scene. An onboard camera of an aircraft collects a highly overlapped set of oblique images that are well suited for preparing three dimensional meshes that model complex scenes with significant vertical relief. The aircraft is flown in a radial trajectory over a targeted observable area in order to collect the images. The radial trajectory is optimized using parameters including an altitude, a field-of-view angle, an aft edge angle, and a forward edge angle of the onboard camera, as well as an expected velocity of the aircraft. A flight management system is also employed, wherein the flight management system computes a predicted location for the aircraft using location data and a current velocity of the aircraft. The predicted location being compared to an expected location, ensuring proper navigation of the radial trajectory.

Claims

1. A method for airborne oblique image collection comprising:

providing a flight management system;

providing an aircraft, the aircraft comprising an onboard camera having a boresight;

navigating, by the aircraft, a first radial trajectory over a targeted observable region, the first radial trajectory being in a first overlapping looping pattern, the first overlapping looping pattern being formed by a plurality of first overlapping circles, each of the plurality of first overlapping circles comprising a first center, the plurality of first centers being positioned along a first linear path, the first linear path traversing across the targeted observable region;

fixating, by the aircraft, the boresight about a first focal point of the targeted observable region throughout the first radial trajectory, the first focal point traversing along the first linear path throughout the first radial trajectory;

sending, by the flight management system, a first camera fire command to the onboard camera;

collecting, by the onboard camera, first image frames in response to the first camera fire command being sent to the onboard camera;

sending, by the flight management system, a first camera kill command to the onboard camera;

stop collecting, by the onboard camera, the first image frames in response to first the camera kill command being sent to the onboard camera;

computing, by the flight management system, a first predicted location for the aircraft;

comparing, by the flight management system, the first predicted location to a first expected location along the first radial trajectory;

instructing, by the flight management system, the aircraft to adjust a first current flight path in response to the first predicted location not matching the first expected location;

instructing, by the flight management system, the aircraft to adhere to the first current flight path in response to the first predicted location matching the first expected location;

navigating, by the aircraft, a second radial trajectory over the targeted observable region, the second radial trajectory being in a second overlapping looping pattern, the second overlapping looping pattern being formed by a plurality of second overlapping circles, each of the plurality of second overlapping circles comprising a second center, the plurality of second centers being positioned along a second linear path, the second linear path traversing across the targeted observable region, the first radial trajectory and the second radial trajectory overlapping each other, the first linear path and the second linear path being parallel to each other;

fixating, by the aircraft, the boresight about a second focal point of the targeted observable region throughout the second radial trajectory, the second focal point traversing along the second linear path throughout the second radial trajectory;

sending, by the flight management system, a second camera fire command to the onboard camera;

collecting, by the onboard camera, second image frames in response to the second camera fire command being sent to the onboard camera;

sending, by the flight management system, a second camera kill command to the onboard camera;

stop collecting, by the onboard camera, the second image frames in response to the second camera kill command being sent to the onboard camera;

computing, by the flight management system, a second predicted location for the aircraft;

comparing, by the flight management system, the second predicted location to a second expected location along the second radial trajectory;

instructing, by the flight management system, the aircraft to adjust a second current flight path in response to the second predicted location not matching the second expected location; and

instructing, by the flight management system, the aircraft to adhere to the second current flight path in response to the second predicted location matching the second expected location.

2. The method for airborne oblique image collection as claimed in claim 1, wherein the onboard camera observes a first primary coverage area and a first redundant coverage area within the first radial trajectory and a second primary coverage area and a second redundant coverage area within the second radial trajectory.

3. The method for airborne oblique image collection as claimed in claim 1 comprising:

receiving, by the flight management system, a first location data for the aircraft and a first current velocity for the aircraft; and

receiving, by the flight management system, a second location data for the aircraft and a second current velocity for the aircraft.

4. The method for airborne oblique image collection as claimed in claim 1 comprising:

calculating, by the flight management system, a first predicted radius about the first focal point for the aircraft;

comparing, by the flight management system, the first predicted radius to a first expected radius of the first radial trajectory;

instructing, by the flight management system, the aircraft to increase a first bank angle in response to the first predicted radius being larger than the first expected radius;

instructing, by the flight management system, the aircraft to decrease the first bank angle in response to the first predicted radius being smaller than the first expected radius;

instructing, by the flight management system, the aircraft to maintain the first bank angle in response to the first predicted radius being equal to the first expected radius;

calculating, by the flight management system, a second predicted radius about the second focal point for the aircraft;

comparing, by the flight management system, the second predicted radius to a second expected radius of the second radial trajectory;

instructing, by the flight management system, the aircraft to increase a second bank angle in response to the second predicted radius being larger than the second expected radius;

instructing, by the flight management system, the aircraft to decrease the second bank angle in response to the second predicted radius being smaller than the second expected radius; and

instructing, by the flight management system, the aircraft to maintain the second bank angle in response to the second predicted radius being equal to the second expected radius.

5. The method for airborne oblique image collection as claimed in claim 1 comprising:

receiving, by the flight management system, the first radial trajectory from a computing device; and

receiving, by the flight management system, the second radial trajectory from the computing device.

6. The method for airborne oblique image collection as claimed in claim 1 comprising:

providing a computing device for plotting the first radial trajectory and the second radial trajectory;

receiving, by the computing device, a first altitude, a first aft edge angle, a first forward edge angle and a first field-of-view angle for the onboard camera;

calculating, by the computing device, a first expected radius for the first radial trajectory using the first altitude, the first aft edge angle, the first forward edge angle and the first field-of-view angle;

receiving, by the computing device, a second altitude, a second aft edge angle, a second forward edge angle and a second field-of-view angle for the onboard camera; and

calculating, by the computing device, a second expected radius for the second radial trajectory using the second altitude, the second aft edge angle, the second forward edge angle and the second field-of-view angle.

7. The method for airborne oblique image collection as claimed in claim 6 comprising:

receiving, by the computing device, a first expected velocity for the aircraft;

calculating, by the computing device, a first expected bank angle for the aircraft using the first expected velocity and the first expected radius;

calculating, by the computing device, a first camera tilt angle using the first aft edge angle, the first field-of-view angle and the first expected bank angle, the boresight being oriented at the first camera tilt angle with respect to a first yaw axis of the aircraft;

receiving, by the computing device, a second expected velocity for the aircraft;

calculating, by the computing device, a second expected bank angle for the aircraft using the second expected velocity and the second expected radius; and

calculating, by the computing device, a second camera tilt angle using the second aft edge angle, the second field-of-view angle and the second expected bank angle, the boresight being oriented at the second camera tilt angle with respect to a second yaw axis of the aircraft.

8. The method for airborne oblique image collection as claimed in claim 1 comprising:

providing a display screen for the aircraft; and

displaying, by the display screen, the first radial trajectory, the first predicted location, the second radial trajectory, the second predicted location, a steering error indicator and a speed error indicator.

9. The method for airborne oblique image collection as claimed in claim 8, wherein the steering error indicator compares a first bank angle for the aircraft to a first expected bank angle for the aircraft and compares a second bank angle for the aircraft to a second expected bank angle for the aircraft.

10. The method for airborne oblique image collection as claimed in claim 8, wherein the speed error indicator compares a first current velocity for the aircraft to a first expected velocity for the aircraft and compares a second current velocity for the aircraft to a second expected velocity for the aircraft.