Relation to underwater imaging for underwater surveys

• US 10,116,841 B2
• Filed: 10/17/2013
• Issued: 10/30/2018
• Est. Priority Date: 10/17/2012
• Status: Active Grant

• Current Assignee: Cathx Research Ltd.
• Original Assignee: Cathx Research Ltd.
• Inventors: Boyle, Adrian, Flynn, Michael
• Primary Examiner(s): Perungavoor, Sathyanaraya V
• Assistant Examiner(s): Dhillon, Peet
• Application Number:
  US14/436,868
• Publication Number:
  US 20160198074A1
• Time in Patent Office: 1,839 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 3/08 Use of electric radiation detectors
• CPC Class Codes: G06F 16/58 Retrieval characterised by using metadata, e.g. metadata not derived from the content or metadata generated manually
• CPC Class Codes: G06F 16/5866 using information manually generated, e.g. tags, keywords, comments, manually generated location and time information
• CPC Class Codes: G06F 16/587 using geographical or spatial information, e.g. location
• CPC Class Codes: G06T 1/0007 Image acquisition
• CPC Class Codes: G06T 11/00 2D [Two Dimensional] image generation
• CPC Class Codes: G06T 2200/32 involving image mosaicing
• CPC Class Codes: G06T 2207/10144 Varying exposure
• CPC Class Codes: G06T 2207/10152 Varying illumination
• CPC Class Codes: G06T 3/4038 Image mosaicing, e.g. composing plane images from plane sub-images
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 23/90 Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums
• CPC Class Codes: H04N 5/265 Mixing
• CPC Class Codes: H04N 7/18 Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast
• CPC Class Codes: Y02A 90/30 Assessment of water resources

Abstract

The present invention relates to methods and systems for performing underwater surveys, in particular on sub-sea installations such as oil and gas pipelines, risers, well-heads and so on. Further the invention relates to providing an augmented underwater image of a scene for use in an under-water survey, using an underwater imaging system comprising a light module, image processing module and a camera module, the light module comprising a plurality of light classes each light class having one or more light sources. The invention uses sequential imaging to provide the augmented output image.

Claims

1. A method of capturing sequential underwater image data of a scene for use in an underwater survey, the method operating in an underwater imaging system comprising a light module, an image processing module, a camera module, and a sequential imaging module, the light module comprising a plurality of light classes each light class having one or more light sources, wherein the steps of the method comprise:

the camera module capturing a sequence of images of each of a plurality of overlapping fields of view within the scene, where the scene is illuminated by one or more of the light classes of the light module;

the sequential imaging module controlling the operational parameters of the light module and camera module to adjust lighting and imaging parameters between individual image captures such that a time relationship of the lighting and imaging parameters to individual image captures in the sequence of images in each of the plurality of overlapping fields of view is predetermined, and a time relationship of the lighting and imaging parameters to image captures with different light classes in each of the plurality of overlapping fields of view is predetermined; and

the image processing module concatenating the individual images to form a set of images that are related to each other.

2. A method as claimed in claim 1, wherein one light class of the light module is adapted to emit white light.

3. A method as claimed in claim 1, wherein a light class of the light module is adapted to emit light with a wavelength between 10 nm and 760 nm.

4. A method as claimed in claim 1, wherein one light class of the light module is a reference projection light class, wherein a light source of the reference projection light class is adapted to emit a structured light beam.

5. A method as claimed in claim 4, wherein the structured light beam is parallel with the orientation of the camera module.

6. A method as claimed in claim 4, wherein the structured light beam is angularly off-set from the orientation of the camera module.

7. A method as claimed in claim 4, wherein the reference projection light class comprises a pair of identical light sources, each an equal distance from the camera module.

8. A method as claimed in claim 7, wherein the light sources emit parallel beams, or the light sources emit non-parallel beams.

9. A method as claimed in claim 1, in which all comprising the sequential imaging module controlling the operational parameters of the camera module to adjust imaging parameters between individual image captures.

10. A method as claimed in claim 4, comprising the image processing module deriving measurements for use in the set of images from the captured image of the structured light beam.

11. A method as claimed in claim 1, wherein the step of concatenating the individual images to form a set of images comprises the image processing module carrying out machine vision analysis of one or more of the captured images to identify useful aspects thereof.

12. A method as claimed in claim 1, wherein the underwater imaging system further comprises a location module, adapted to determine its own location, wherein the method includes the additional steps of:

the location module generating a location label comprising information identifying the current location when an image is captured; and

attaching the location label to the set of images.

13. A method of providing an augmented underwater video sequence comprising carrying out the steps of the method of claim 1 at a desired frame rate.

16. A method as claimed in claim 3, wherein a light class of the light module is adapted to emit ultraviolet (UV) light.

17. A method as claimed in claim 3, wherein a light class of the light module is adapted to emit visible light of a specific color.

18. A method as claimed in claim 4, wherein the structured light beam is adapted to project a pair of parallel lines on a target.

19. A method as claimed in claim 4, wherein the structured light beam is adapted to project a grid on a target.

20. A method as claimed in claim 11, comprising carrying out object detection on one or more of the captured images.

14. An underwater imaging system for capturing sequential underwater image data of a scene, the underwater imaging system comprising a light module, an image processing module, a camera module, and a sequential imaging module, the light module comprising a plurality of light classes, each light class having one or more light sources, wherein

the camera module is configured to capture a sequence of images of each of a plurality of overlapping fields of view within the scene, where the scene is illuminated by one or more of the light classes of the light module;

the sequential imaging module is configured to control the operational parameters of the light module and camera module to adjust lighting and imaging parameters between individual image captures such that a time relationship of the lighting and imaging parameters to individual image captures in the sequence of images in each of the plurality of overlapping fields of view is predetermined, and a time relationship of the lighting and imaging parameters to image captures with different light classes in each of the plurality of overlapping fields of view is predetermined; and

the image processing module is configured to concatenate the individual images to form a set of images that are related to each other.

15. An unmanned submersible vehicle comprising the underwater imaging system of claim 14.