Side-View Camera Inspection Tool with Curved Sapphire Window

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Solution Overview

Problem

Existing downhole inspection tools face issues with distorted images, slow 360° view capture, and uneven illumination, particularly when dealing with varying pipe diameters and limited memory capabilities.

Innovation Solution

An inspection assembly with a cylindrical housing, side-view cameras, and angled light sources, utilizing a sapphire window element with a concave external surface to ensure even illumination of the field of view, allowing for efficient 360° imaging in pipes with varying diameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a wide angle camera is positioned at the end of the tool to capture 360° view, then the field of view covers a region ahead of the tool, but the image becomes highly distorted especially at the periphery with optical compression increasing near the edges

Engineering Contradiction:
Improvefield of view coverageVSAvoidimage distortion
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

Instead of positioning the camera at the end of the tool pointing forward, the invention positions the camera on the side of the tool pointing radially outward. This inverted arrangement eliminates the need for extreme wide-angle lenses and their associated peripheral distortion, while still achieving 360° coverage through rotation or multiple cameras.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention transitions from a single forward-pointing camera (one-dimensional viewing) to side-view cameras that can rotate or be arranged circumferentially (adding rotational or circumferential dimension). This dimensional change enables 360° coverage without the distortion problems of extreme wide-angle lenses.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If a single sideview camera is rotated to capture 360° view, then the full circumference can be imaged, but the process is slow and requires motor rotation which may fail

Engineering Contradiction:
Improve360° view coverageVSAvoidimaging speed
Core Design Contradiction:
Area of stationary objectVSProductivity

Solution Approach 1:

Instead of using a single rotating camera, the invention segments the imaging function into multiple fixed cameras arranged circumferentially around the tool. Each camera captures a portion of the 360° view simultaneously, eliminating the need for rotation and enabling immediate full-circumference imaging.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cameras are pre-positioned at specific circumferential locations before deployment. This preliminary arrangement ensures that all required viewing angles are covered simultaneously upon activation, eliminating the time required for rotational movement and enabling immediate 360° imaging.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If multiple cameras are located around the circumference to cover 360° view, then the full view can be captured simultaneously, but achieving even distribution of light over the full field of view becomes difficult when pipe diameter varies

Engineering Contradiction:
Improvesimultaneous 360° imagingVSAvoidlight distribution uniformity
Core Design Contradiction:
ProductivityVSIllumination intensity

Solution Approach 1:

The invention uses a curved or spherical diffusing element positioned around the light source. This curved geometry naturally distributes light in a radially symmetric pattern, ensuring uniform illumination across all circumferential cameras regardless of the pipe's internal diameter, thereby solving the light distribution problem.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The diffusing element's curved geometry changes the light propagation parameters, transforming the light distribution from a directional pattern to a radially symmetric pattern. This parameter change ensures that light intensity remains uniform across all camera fields of view, independent of pipe diameter variations.

Inventive Principle:
Principle #35Parameter changes

4Illumination intensity

If high-intensity light sources are used to illuminate the field of view, then adequate lighting is achieved, but the tool diameter and length increase

Engineering Contradiction:
Improvefield of view illuminationVSAvoidtool length
Core Design Contradiction:
Illumination intensityVSLength of stationary object

Solution Approach 1:

The invention introduces a diffusing element as an intermediary between the light source and the field of view. This mediator distributes the light from a compact source uniformly across all camera fields of view, achieving adequate illumination without requiring high-intensity sources that would increase tool size.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The curved diffusing element efficiently distributes light from a compact source in all radial directions, maximizing illumination coverage within a minimal volume. This curved geometry allows adequate lighting to be achieved without increasing tool diameter or length significantly.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides clear, even illumination and efficient 360° imaging, reducing the need for high-intensity light sources and minimizing tool diameter and length, while being practical for deployment on slickline or e-line cables.

Implementation Method 1

a window element mounted in the housing, the element comprising a light transmitting material and being located such that light emitted by the light source passes through the window before illuminating the field of view

Methodology Applied
Scientific EffectLight transmission: Light

Implementation Method 2

the window has an internal surface, closer to the light source, and an external surface, further from the light source, and wherein the external surface comprises a concave region

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3571378B1Inspection assembly lighting system
Publication Date: 2022.03.30 E V OFFSHORE LTD
  • EP3571378B1 patent drawingFigure 1~3
  • EP3571378B1 patent drawingFigure 4~5

AI summary

This invention relates to the field of inspection assemblies and in particular to inspection assemblies that include light sources for illuminating a field of view of a camera. An inspection assembly for imaging the internal surface of a pipe or conduit comprises 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.