Offshore positioning system and method

• US 10,323,941 B2
• Filed: 02/28/2013
• Issued: 06/18/2019
• Est. Priority Date: 02/28/2013
• Status: Active Grant

• Current Assignee: Fnv IP B.V.
• Original Assignee: Fugro N.V.
• Inventors: Booij, Olaf, Nejadasl, Fatemeh Karimi, Schippers, Evert, Wouters, Hendrik
• Primary Examiner(s): Cattungal, Rowina J
• Application Number:
  US14/770,761
• Publication Number:
  US 20160010989A1
• Time in Patent Office: 2,301 Days
• CPC Class Codes: G01B 11/26 for measuring angles or tapers; for testing the alignment of axes
• 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 11/06 by comparison of two or more pictures of the same area
• CPC Class Codes: G01C 9/00 Measuring inclination, e.g. by clinometers, by levels
• CPC Class Codes: H04N 23/62 Control of parameters via user interfaces
• CPC Class Codes: H04N 23/741 by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors
• CPC Class Codes: H04N 7/181 for receiving images from a plurality of remote sources

Abstract

A system for measuring the attitude of an object in a fixed frame of reference from a moving frame of reference, comprising a first imaging device for producing image data for the object from a first direction, a second imaging device for producing image data for the object from a second direction having a component perpendicular to the first direction and an attitude sensing arrangement for determining an attitude of the first and second imaging devices with respect to the fixed frame of reference at the time the respective images are taken and for generating attitude data. An image processing system analyses and combines the respective image data and attitude data to determine the attitude of the object. The system is particularly useful for determining attitude of offshore piles during piling operations or for monitoring the departure angles of pipes and cables during laying thereof.

Claims

1. A system for measuring in real time an attitude of an object in a fixed frame of reference from a moving frame of reference, the system comprising:

a first imaging device configured to produce image data for the object from a first direction in the moving frame of reference;

a second imaging device configured to produce image data for the object from a second direction in the moving frame of reference, the second direction having a component perpendicular to the first direction;

an attitude sensing arrangement configured to determine an attitude of the first and second imaging devices with respect to the fixed frame of reference at the time the respective images are taken and configured to generate attitude data;

an image processing system configured to analyze and combine the respective image data and attitude data to determine the real time attitude of the object; and

the image processing system further configured to determine verticality of the object having a central axis, wherein the image processing system configured to;

determine left and right border planes of the object from the first imaging device and identify a location of a first plane passing through the first imaging device and being equidistance from the observed left and right border planes;

determine left and right border planes of the object from the second imaging device and identify a location of a second plane passing through the second imaging device and being equidistance from the observed left and right border planes; and

identify an intersection of the first and second planes observed from both the first and second imaging devices to determine the attitude of the central axis of the object.

2. The system according to claim 1, wherein the attitude sensing arrangement comprises a three-axis attitude sensor with heading indicator.

3. The system according to claim 1, wherein the attitude sensing arrangement comprises first and second attitude sensors, each integrated with a respective imaging device for movement therewith in the moving frame of reference.

4. The system according to claim 1, further comprising a clock, arranged to time stamp the image data relative to the attitude data.

5. The system according to claim 1, wherein the first and second imaging devices are mounted aboard the vessel and the attitude of the object is given with respect to a heading of the vessel.

6. The system according to claim 1, wherein the first and second imaging devices are mounted aboard the vessel and the attitude of the object is given with respect to a geodetic co-ordinate frame.

7. The system according to claim 1, further comprising a calibration facility arranged to calibrate a total roll error of the first and second imaging devices.

8. The system according to claim 1, further comprising an attitude display providing a real-time representation of the attitude of the object.

9. The system according to claim 1, further comprising a user interface and an image display and the image processing system is arranged such that a user can manually pick a portion of an image of the object on the display for use in determining the attitude of the object.

10. A device configured to communicate with a data processing system for measuring in real time an attitude of an object in a fixed frame of reference from a moving frame of reference, the device comprising:

an imaging device configured to produce images of the object in the moving frame of reference;

an attitude sensor configure to determine an attitude of the object with respect to the fixed frame of reference at the time the images are taken and for generating attitude data, the attitude sensor having a dynamic accuracy of better than 1.0 degrees, at least in pitch and roll directions;

a clock, arranged to time stamp the attitude data; and

a communication port configured to transmit data;

wherein the data processing system is configured to receive transmitted data from the device and from a second similar device, configured to determine and display in real time the attitude of the object and configured to determine verticality of the object having a central axis by;

determining left and right border planes of the object from the imaging device and identify a location of a first plane passing through the first imaging device and being equidistance from the observed left and right border planes;

determining left and right border planes of the object from the second similar device and identify a location of a second plane passing through the second similar device and being equidistance from the observed left and right border planes; and

identifying an intersection of the first and second planes observed from both the imaging device and the second similar device to determine the attitude of the central axis of the object.

11. The device according to claim 10, wherein the data processing system is remote from the imaging device and the images and attitude data is transmitted to the data processing system.

12. The device according to claim 10, wherein the device is portable and the imaging device and the attitude sensor are fixed to each other to prevent relative movement.

13. The device according to claim 10, wherein the imaging device is a digital camera having automatic iris control.

14. The device according to claim 10, further comprising a calibration facility arranged to calibrate a total roll error of the device.

15. The device according to claim 10, further comprising a global navigation satellite system device providing position data for the imaging device.

16. A vessel comprising the device of claim 10.

17. A method of determining an attitude of an offshore object in a fixed frame of reference based on observations from a vessel moving in a moving frame of reference, the method comprising:

receiving data from a first imaging device including the object from the moving frame of reference in a first direction to produce a first image data set;

receiving data from a second imaging device the object from the moving frame of reference in a second direction not co-linear with the first direction to produce a second image data set;

collecting, at an attitude sensing arrangement, attitude data representing a relative attitude of the moving frame of reference with respect to the fixed frame of reference for each image data set;

analysing and combining, at an image processing system, the respective image data and attitude data to determine the attitude of the object; and

determining, at the image processing system, verticality of the object having a central axis by;

determining left and right border planes of the object from the first imaging device and identify a location of a first plane passing through the first imaging device and being equidistance from the observed left and right border planes;

determining left and right border planes of the object from the second imaging device and identify a location of a second plane passing through the second imaging device and being equidistance from the observed left and right border planes; and

identifying an intersection of the first and second planes observed from both the first and second imaging devices to determine the attitude of the central axis of the object.

18. The method of claim 17, wherein the first direction is generally perpendicular to the second direction.

19. The method according to claim 17, wherein the object is an offshore pile and the attitude determines a verticality of the offshore pile during driving thereof.

20. The method according to claim 17, wherein the object is a cable or pipe from a vessel and the attitude determines for a departure trajectory of the cable or pipe from the vessel during laying thereof.

21. A non-transitory computer readable medium storing instructions which when executed by a processor, causes the processor to:

receive data, from a first imaging device, including an object from a moving frame of reference in a first direction to produce a first image data set;

receive data, from a second imaging device, including the object from the moving frame of reference in a second direction not co-linear with the first direction to produce a second image data set;

collect attitude data representing a relative attitude of the moving frame of reference with respect to a fixed frame of reference for each image data set;

analyze and combine the respective image data and attitude data to determine the attitude of the object; and

determine verticality of the object having a central axis by;

determining left and right border planes of the object from the first imaging device and identify a location of a first plane passing through the first imaging device and being equidistance from the observed left and right border planes;

determining left and right border planes of the object from the second imaging device and identify a location of a second plane passing through the second imaging device and being equidistance from the observed left and right border planes; and

identifying an intersection of the first and second planes observed from both the first and second imaging devices to determine the attitude of the central axis of the object.

22. The non-transitory computer readable medium according to claim 21, comprising further instructions, which when executed by the processor causes the processor to:

acquire time-stamped first and second image data sets;

acquire time-stamped attitude data;

determine a central plane of the object for each of the first and second image data sets;

combine attitude data with the central planes for the first and second image data sets, for producing an estimate of the attitude; and

display the estimated attitude.

23. The non-transitory computer readable medium according to claim 22, wherein the estimated attitude is displayed as a spirit-level bubble.