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: This invention relates to a method of imaging a downhole region of interest. In particular this invention relates to a method of processing images captured downhole to remove or reduce distortions due to the optical system as a function of the temperature experienced by the optical system in the downhole environment. A method of imaging a downhole region of interest comprises contemporaneously capturing an image of a region of interest and recording a temperature associated with the region of interest; selecting a pre-defined set of distortion data from a plurality of pre-defined sets of distortion data based on the recorded temperature; and applying the selected set of distortion data to the captured image to create an un-distorted image, wherein the pre-defined set of distortion data comprises distortion values associated with a range of field angles at a specified temperature.

Abstract: Inspection assemblies that include one or more sideview cameras for capturing images of an interior surface of a pipe or conduit include an elongate housing, a sideview camera within the housing and arranged to capture an image of a region within a field of view external to the housing, and a viewport element mounted in the housing and located such that light is transmitted through the viewport element and into said sideview camera, wherein the viewport element has a concave internal surface, closer to the camera, and a convex external surface, further from the camera, and wherein the centre of the radius of curvature of the internal surface is closer to the viewport element than the centre of the radius of curvature of the external surface.

Abstract: The field of inspection assemblies and in particular to inspection assemblies that include light sources for illuminating a field of view of a camera including an elongate housing having a longitudinal axis, a camera mounted in the housing and arranged to capture an image of a region within a field of view external to the housing, a light source mounted in the housing and arranged to illuminate the field of view, and a window element mounted in the housing, the window element comprising a light transmitting material and being located such that light emitted by the light source passes through the window element before illuminating the field of view. The window element has an internal surface, closer to the light source, and an external surface, further from the light source, and the external surface comprises a concave region.

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 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: Inspection assemblies that include one or more sideview cameras for capturing images of an interior surface of a pipe or conduit include an elongate housing, a sideview camera within the housing and arranged to capture an image of a region within a field of view external to the housing, and a viewport element mounted in the housing and located such that light is transmitted through the viewport element and into said sideview camera, wherein the viewport element is diffusion bonded to a metal support.

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: An optical cap that protects a camera lens of the inspection assembly is disclosed herein. The disclosed optical cap for an inspection assembly may include an optically clear dome-shaped window element and a metal collar attached to the window element, the collar including means for securing the optical cap to said inspection assembly, wherein the collar is bonded to the window element by means of brazing or welding.

Abstract: This invention relates to an inspection assembly comprising a light source and a lens. In particular this invention relates to the provision of a reflection surface for improving the illumination of a field of view of a wide angle camera. An inspection assembly comprises a main body having a longitudinal axis and a distal end; a lens located at the distal end; a light source positioned to illuminate an area beyond the distal end of the main body; and a reflection surface, an angle between the reflection surface and the longitudinal axis of the main body being between 10° and 70°, wherein the reflection surface is positioned such that, in use, a first fraction of the light emitted by the light source is reflected by the reflection surface and a second fraction of the light emitted by the light source travels to an area beyond the distal end of the main body without being reflected by said surface.

Abstract: The field of inspection assemblies and in particular to inspection assemblies that include light sources for illuminating a field of view of a camera including an elongate housing having a longitudinal axis, a camera mounted in the housing and arranged to capture an image of a region within a field of view external to the housing, a light source mounted in the housing and arranged to illuminate the field of view, and a window element mounted in the housing, the window element comprising a light transmitting material and being located such that light emitted by the light source passes through the window element before illuminating the field of view. The window element has an internal surface, closer to the light source, and an external surface, further from the light source, and the external surface comprises a concave region.

Abstract: This invention is designed for use in transmission of data between downhole module in a wellbore and a controlling module at the surface. The invention provides an apparatus for receiving data signals from a telemetry module comprising first and second adaptive equalisers, and in which in a first modulation mode the coefficients of the first adaptive equaliser are updated until an error signal falls below a predetermined threshold and in a second modulation mode the coefficients of the first adaptive equaliser are locked and coefficients of the second adaptive equaliser are updated to continually minimise an error signal in which the number of bits encoded by the symbols of the first signal in an initial modulation mode is fewer than the number of bits encoded by the symbols of the second signal in a subsequent modulation mode.

Abstract: Inspection assemblies that include one or more sideview cameras for capturing images of an interior surface of a pipe or conduit include an elongate housing, a sideview camera within the housing and arranged to capture an image of a region within a field of view external to the housing, and a viewport element mounted in the housing and located such that light is transmitted through the viewport element and into said sideview camera, wherein the viewport element has a concave internal surface, closer to the camera, and a convex external surface, further from the camera, and wherein the centre of the radius of curvature of the internal surface is closer to the viewport element than the centre of the radius of curvature of the external surface.

Abstract: Inspection assemblies that include one or more sideview cameras for capturing images of an interior surface of a pipe or conduit include an elongate housing, a sideview camera within the housing and arranged to capture an image of a region within a field of view external to the housing, and a viewport element mounted in the housing and located such that light is transmitted through the viewport element and into said sideview camera, wherein the viewport element is diffusion bonded to a metal support.

Abstract: An optical cap that protects a camera lens of the inspection assembly is disclosed herein. The disclosed optical cap for an inspection assembly may include an optically clear dome-shaped window element and a metal collar attached to the window element, the collar including means for securing the optical cap to said inspection assembly, wherein the collar is bonded to the window element by means of brazing or welding.

Abstract: This invention relates to an inspection assembly comprising a light source and a lens. In particular this invention relates to the provision of a reflection surface for improving the illumination of a field of view of a wide angle camera. An inspection assembly comprises a main body having a longitudinal axis and a distal end; a lens located at the distal end; a light source positioned to illuminate an area beyond the distal end of the main body; and a reflection surface, an angle between the reflection surface and the longitudinal axis of the main body being between 10° and 70°, wherein the reflection surface is positioned such that, in use, a first fraction of the light emitted by the light source is reflected by the reflection surface and a second fraction of the light emitted by the light source travels to an area beyond the distal end of the main body without being reflected by said surface.

Abstract: An inspection apparatus for use in wellbores in the oil and gas industries relates in general to the field of transmission of data between downhole module in a wellbore and a controlling module at the surface. The invention provides a method and apparatus for determining analog filter parameters for an analog front end comprising a plurality of filter stages receiving signals from a telemetry module, by repeating the steps of; receiving a signal of a known frequency and processing said signal by determining the magnitude of the frequency of the received signal until a plurality of signals have been received and processed; calculating an optimum set of filter parameters in dependence upon the measured frequency magnitudes and a predefined set of filter stage frequency responses.