Methods and systems for determining angles and locations of points

• US 8,351,686 B2
• Filed: 01/08/2010
• Issued: 01/08/2013
• Est. Priority Date: 01/08/2009
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Graesser, Christian
• Primary Examiner(s): Johns, Andrew W
• Assistant Examiner(s): Harandi, Siamak
• Application Number:
  US13/143,320
• Publication Number:
  US 20120013736A1
• Time in Patent Office: 1,096 Days
• Field of Search: None
• US Class Current: 382/154
• CPC Class Codes: G01C 15/06 Surveyors' staffs; Movable markers
• CPC Class Codes: G06T 2207/30204 Marker
• CPC Class Codes: G06T 7/73 using feature-based methods

Abstract

An apparatus for determining an azimuth of a target point is provided. The apparatus includes a support structure and an imaging device coupled to the support structure and configured to provide image data. The apparatus also includes a position measuring device coupled to the support structure and configured to determine position information and a processor in electrical communication with the imaging device and the position measuring device. The processor is configured to receive the image data from the imaging device, receive the position information from the position measuring device, determine a baseline between a first position and a second position, determine an orientation between overlapping images, and compute the azimuth of the target point relative to the baseline.

Claims

1. An apparatus for determining an azimuth of a target point comprising:

a support structure;

an imaging device coupled to the support structure and configured to provide image data;

a position measuring device coupled to the support structure and configured to determine position information; and

a processor in electrical communication with the imaging device and the position measuring device, wherein the processor is configured to;

receive the image data from the imaging device;

receive the position information from the position measuring device;

determine a baseline between a first position and a second position;

determine an orientation between overlapping images; and

compute the azimuth of the target point, the azimuth being an angle between the baseline and a line extending from either the first position or the second position to the target point.

2. The apparatus of claim 1 further comprising:

a tilt sensor configured to determine a vertical alignment of the support structure relative to a local gravity vector.

3. The apparatus of claim 2 further comprising:

a distance measuring device coupled to the support structure; and

a vertical angle sensor coupled to the support structure and configured to determine a vertical angle of the distance measuring device relative to the support structure, wherein the distance measuring device and the vertical angle sensor are in electrical communication with the processor, and wherein the processor is further configured to;

receive distance information from the distance measuring device;

receive angle information from the vertical angle sensor; and

compute coordinates of the target point in a local coordinate frame.

4. The apparatus of claim 1 wherein the position measuring device includes a reflective target.

5. The apparatus of claim 1 wherein the imaging device is calibrated to provide angular relationships between elements of the image data.

6. The apparatus of claim 1 wherein the position measuring device includes a global navigation satellite system.

7. The apparatus of claim 1 wherein the imaging device comprises a digital camera.

8. The apparatus of claim 1 wherein the support structure comprises a pole having a vertical axis extending along a length of the pole, and wherein an optical center of the imaging device is aligned with the vertical axis of the pole.

9. A method of determining an azimuth of a target point, the method comprising:

at a first location;

positioning an imaging device at the first location;

orienting the imaging device with respect to a reference position having known coordinates in a local coordinate frame;

obtaining a first image of a surface from the first location;

determining a position of the first location;

orienting the imaging device with respect to the target point; and

obtaining a second image of the surface from the first location, wherein a portion of the first image overlaps a portion of the second image;

determining an orientation of the first image relative to the second image; and

determining the azimuth of the target point relative to the reference position.

10. The method of claim 9 further comprising:

determining a distance from the first location to the target point; and

computing coordinates of the target point in the local coordinate frame.

11. The method of claim 9 further comprising obtaining a third image from a second location, wherein the reference position comprises a baseline extending from the first location to the second location, and wherein the first image is oriented with respect to the reference position using overlapping portions of the first image obtained from the first location and the third image obtained from the second location.

12. The method of claim 9 wherein a second target point is located within the second image and the surface is substantially flat, the method further comprising:

computing coordinates of the second target point in the local coordinate frame using a calibration of the imaging device.

13. A method of determining coordinates of a target point in a local coordinate frame, the method comprising:

computing a baseline as a function of a first location and a second location;

obtaining a first image of a surface from the second location using an imaging device;

orienting the first image relative to the baseline;

aligning the imaging device with the target point;

obtaining a second image of the surface from the second location with the imaging device aligned with the target point;

determining an orientation of the second image relative to the first image;

computing the azimuth of the target point;

determining a distance from the second location to the target point; and

computing the coordinates of the target point in the local coordinate frame.

14. The method of claim 13 further comprising obtaining a third image from the first position, wherein the first image is oriented relative to the baseline using overlapping portions of the first image and the third image.

15. The method of claim 13 further comprising:

determining a first position of the first location in the local coordinate frame; and

determining a second position of the second location in the local coordinate frame.

16. A method of determining coordinates in a local coordinate frame of a target point on a substantially flat surface, the method comprising:

obtaining a first image of a surface from a first location using a calibrated imaging device that includes angular relationships between elements of image data;

determining a position of the first location in the local coordinate frame;

obtaining a second image of the substantially flat surface from a second location using the calibrated imaging device, the second image including the target point, wherein the first location is different from the second location and a portion of the first image overlaps a portion of the second image;

determining a position of the second location in the local coordinate frame;

computing an azimuth of the second image; and

computing the coordinates of the target point in the local coordinate frame.

17. The method of claim 16 wherein the azimuth of the second image is computed using the position of the first location in the local coordinate frame, the position of the second location in the local coordinate frame, and features in the portion of the first image that overlaps the portion of the second image.

18. The method of claim 16 wherein the location of the target point in the local coordinate frame is computed using calibration of the imaging device and the azimuth of the second image.

19. The method of claim 16 wherein the substantially flat surface is characterized by a slope, the method further comprising:

determining a position of a third location in the local coordinate system;

computing the slope of the surface; and

determining the coordinates of the target point on the substantially flat surface based on the slope.