Abstract: A method for constructing a three-dimensional representation of an internal surface of a conduit comprises obtaining a plurality of images of the internal surface of the conduit, for example from a camera mounted on an inspection tool, constructing, from the plurality of images, a composite image of the internal surface, providing a shape model of the internal surface, constructing, using the shape model, a three-dimensional mesh of the internal surface, and constructing a three-dimensional representation of the internal surface by assigning a pixel value from the composite image to a corresponding node of the mesh. The three-dimensional representation may be derived from two or more sets of images obtained under different image acquisition conditions, such as different camera angles, lighting conditions or spectral sensitivities.

Abstract: 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.

Abstract: A method for determining a corrected axial displacement parameter of a conduit inspection tool, in particular a downhole inspection tool, during transit of the tool axially along a conduit is disclosed. The tool used in the method has an imaging device and may be attached to a control module with a connecting line. The method comprises obtaining successive axially overlapping images of an internal wall of the conduit, determining, from the images, an observed axial displacement parameter of the tool as a function of transit time, identifying, in the images, a plurality of reference points, determining an estimated axial displacement parameter of the tool over an of transit time between successive reference points, and computing the corrected axial displacement parameter of the tool by applying a correction factor to the observed axial velocity of the tool.

Abstract: A method for determining a corrected axial displacement parameter of a conduit inspection tool, in particular a downhole inspection tool, during transit of the tool axially along a conduit is disclosed. The tool used in the method has an imaging device and may be attached to a control module with a connecting line. The method comprises obtaining successive axially overlapping images of an internal wall of the conduit, determining, from the images, an observed axial displacement parameter of the tool as a function of transit time, identifying, in the images, a plurality of reference points, determining an estimated axial displacement parameter of the tool over an of transit time between successive reference points, and computing the corrected axial displacement parameter of the tool by applying a correction factor to the observed axial velocity of the tool.

Abstract: 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.

Abstract: A method of constructing a three-dimensional model of an internal surface of a tubular structure comprises obtaining image data from an area of the internal surface of the structure, obtaining measured height profile data from the internal surface in a plurality of sub-regions of the area, for example using a multi-finger caliper tool, determining image properties from the image data, correlating the measured height profile data with the image properties in the sub-regions, and constructing expected height profile data for at least part of the area outside the sub-regions using the correlated measured height profile data and image properties.

Abstract: A method for constructing a three-dimensional representation of an internal surface of a conduit comprises obtaining a plurality of images of the internal surface of the conduit, for example from a camera mounted on an inspection tool, constructing, from the plurality of images, a composite image of the internal surface, providing a shape model of the internal surface, constructing, using the shape model, a three-dimensional mesh of the internal surface, and constructing a three-dimensional representation of the internal surface by assigning a pixel value from the composite image to a corresponding node of the mesh. The three-dimensional representation may be derived from two or more sets of images obtained under different image acquisition conditions, such as different camera angles, lighting conditions or spectral sensitivities.

Abstract: A method of constructing a three-dimensional model of an internal surface of a tubular structure comprises obtaining image data from an area of the internal surface of the structure, obtaining measured height profile data from the internal surface in a plurality of sub-regions of the area, for example using a multi-finger caliper tool, determining image properties from the image data, correlating the measured height profile data with the image properties in the sub-regions, and constructing expected height profile data for at least part of the area outside the sub-regions using the correlated measured height profile data and image properties.