Downhole Camera Image Correction for Non-Centered Tool Geometry
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Solution Overview
Problem
Downhole camera images in the oil and gas industry are challenging to interpret due to the camera not being centrally located within the conduit, leading to difficulties in accurately determining feature dimensions and monitoring events, as the camera's position and orientation relative to the pipe axis are often unknown and difficult to determine mechanically.
Innovation Solution
A method involving obtaining overlapping images, identifying common features, determining the tool's position relative to the conduit's axis, and applying correction functions to the image data to accurately assign pixel positions, allowing for precise geometrical corrections and feature dimension calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the inspection tool is deployed in the conduit, then the internal surface can be imaged, but the tool cannot be centrally positioned leading to unknown camera position and orientation
Solution Approach 1:
The patent replaces mechanical position determination methods with an optical/image-based system. By capturing images of the conduit internal surface and analyzing feature positions across multiple images, the system calculates tool position and orientation without mechanical sensors or complex mechanical positioning mechanisms.
Solution Approach 2:
The system uses the imaging data itself to determine tool position rather than requiring separate positioning systems. The conduit wall features visible in the images serve as reference points that automatically provide positioning information, making the system self-sufficient.
2Measurement precision
If images are obtained from a non-centrally located camera, then the internal surface can be viewed, but accurate dimension determination of features becomes difficult
Solution Approach 1:
The patent replaces direct mechanical measurement of feature dimensions with an image-based calculation system. By using the known conduit geometry and the positions of features in corrected images, the system calculates actual dimensions without physical contact or complex measurement devices.
Solution Approach 2:
The system transforms image coordinates into real-world dimensions by applying correction factors derived from tool position and orientation parameters. This parameter transformation enables accurate dimension determination from 2D images despite the non-central camera position.
3Device complexity
If the camera lens is disposed on the tool surface with restricted viewing position, then the tool structure is simple, but points on the conduit surface are observed from unknown distances and angles
Solution Approach 1:
The system uses feedback from identified conduit wall features to determine and correct for the camera's actual position and orientation. By comparing observed feature positions with expected positions based on conduit geometry, the system calculates correction parameters that compensate for the restricted viewing angle.
Solution Approach 2:
The patent transitions from 2D image coordinates to 3D spatial information by incorporating conduit geometry and tool position data. This dimensional transformation enables accurate spatial positioning of features despite the 2D nature of the camera view.
Data Source
AI summary
Methods for correcting for non-centred tool geometry in image data obtained by a conduit inspection tool are disclosed. Embodiments of the invention apply to inspection tools with one or multiple sideview cameras and to inspection tools with downview cameras. The methods include obtaining at least two overlapping images of the internal surface of the conduit using the tool, identifying one or more features common to at least a pair of the overlapping images, determining, based on the positions of the or each common feature, the position of the tool with respect to a longitudinal axis of the conduit, determining a correction function based on the position of the tool and applying the correction function to the image data. Methods for determining the dimension of a feature of interest on the internal surface of the conduit are also disclosed.