STEREO PHOTOGRAMMETRY FROM A SINGLE STATION USING A SURVEYING INSTRUMENT WITH AN ECCENTRIC CAMERA

• US 20090220144A1
• Filed: 01/30/2009
• Published: 09/03/2009
• Est. Priority Date: 02/29/2008
• Status: Active Grant

• Current Assignee: Trimble AB (Trimble Inc.)
• Original Assignee: Trimble AB (Trimble Inc.)
• Inventors: Graesser, Christian, Svanholm, Set, Vogel, Michael, Mein, Nick
• Granted Patent: US 8,897,482 B2
• Time in Patent Office: Days
• US Class Current: 382/154
• CPC Class Codes: G01C 1/04 combined with cameras
• CPC Class Codes: G01C 11/025 by scanning the object
• CPC Class Codes: G01C 15/00 Surveying instruments or accessories not provided for in groups G01C1/00 - G01C13/00
• CPC Class Codes: G06T 2207/10012 Stereo images
• CPC Class Codes: G06T 2207/30181 Earth observation
• CPC Class Codes: G06T 7/593 from stereo images

Abstract

A method for determining, in relation to a surveying instrument, target coordinates of a point of interest, or target, identified in two images captured by a camera in the surveying instrument. The method comprises determining coordinates of the surveying instrument, capturing a first image using the camera in the first camera position; identifying, in the first image, an object point associated with the target; measuring first image coordinates of the object point in the first image; rotating the surveying instrument around the horizontal axis and the vertical axis in order to position the camera in a second camera position; capturing a second image using the camera in the second camera position; identifying, in the second image, the object point identified in the first image; measuring second image coordinates of the object point in the second image; and determining the coordinates of the target in relation to the surveying instrument.

Claims

1. A method for determining coordinates of a target in relation to a surveying instrument having a horizontal axis and a vertical axis, the method comprising:

determining coordinates of the surveying instrument using one or more GNSS signals, wherein the surveying instrument includes a camera positioned eccentric to a rotation center of the surveying instrument;

positioning the camera in a first camera position and orientation;

capturing a first image using the camera in the first camera position and orientation;

identifying, in the first image, an object point associated with the target;

measuring first image coordinates of the object point in the first image;

rotating the surveying instrument around the horizontal axis and the vertical axis in order to position the camera in a second camera position and orientation;

capturing a second image using the camera in the second camera position and orientation;

identifying, in the second image, the object point identified in the first image;

measuring second image coordinates of the object point in the second image; and

determining the coordinates of the target in relation to the surveying instrument based on the coordinates of the surveying instrument, the first image coordinates, and the second image coordinates.

2. The method of claim 1 wherein determining the coordinates of the target is performed external to the surveying instrument.

3. The method of claim 1 wherein the camera is located at a first horizontal distance and a first vertical distance from the rotation center of the surveying instrument.

4. The method of claim 1 wherein identifying the object point in the first image comprises selecting pixel coordinates associated with the target in the first image.

5. The method of claim 1 wherein determining the coordinates of the target further comprises calculating a horizontal angle and a vertical angle from the object point to the camera.

6. The method of claim 1 wherein rotating the surveying instrument comprises first rotating the surveying instrument about the vertical axis and then rotating the surveying instrument about the horizontal axis.

7. The method of claim 6 wherein rotating the surveying instrument about the vertical axis and rotating the surveying instrument about the horizontal axis are performed concurrently.

8. The method of claim 1 wherein identifying, in the second image, the object point identified in the first image includes use of a pattern recognition technique.

9. The method of claim 1 further comprising using camera calibration data to calculate the coordinates of the target in relation to the surveying instrument.

10. The method of claim 1 wherein rotating the surveying instrument comprises using a remote control module adapted to perform the rotation.

11. A computer readable storage medium coupled to a surveying instrument containing instructions which when executed cause a CPU to:

locate the coordinates of the surveying instrument using one or more GNSS signals;

identify an object point in a first image recorded by the surveying instrument;

measure first image coordinates of the object point in the first image;

identify, in a second image recorded by the surveying instrument, the object point identified in the first image;

measure second image coordinates of the object point in the second image; and

calculate coordinates of the object point relative to the location of the surveying instrument based on the coordinates of the surveying instrument, the first image coordinates, and the second image coordinates.

12. The computer readable storage medium of claim 11 wherein the object point in the first image is identified based on a predetermined criteria.

13. The computer readable storage medium of claim 11 wherein the object point in the second image is identified by using a pattern recognition technique.

14. The computer readable storage medium of claim 11 further comprising calculating a distance of the object point from the surveying instrument.

15. The computer readable storage medium of claim 11 further comprising determining a direction of the object point in relation to the surveying instrument.

16. A system for determining coordinates of a target, the system comprising;

a surveying instrument, including a rotation center, adapted to capture images and associated image information of a target location, the surveying instrument comprising;

a camera located eccentric to the rotation center of the surveying instrument;

a GNSS module configured to receive one or more GNSS signals;

a display device configured to display the captured images, the associated image information, and the target coordinates information; and

an input device adapted to receive information identifying an object point;

a memory device coupled to the surveying instrument and configured to store the captured images and the associated image information; and

a CPU coupled to the surveying instrument and configured to accept the associated image information from the surveying instrument and calculate coordinates of the object point identified in the captured images.

17. The system of claim 16 wherein the information identifying an object point characterized by a manual entry.

18. The system of claim 16 wherein the CPU is located internal to the surveying instrument.

19. The system of claim 18 wherein calculating coordinates of the object point is performed by the surveying instrument.

20. The system of claim 16 wherein the memory device is located internal to the surveying instrument.