Meniscus Viewport Assembly for Distortion-Controlled Pipe Inspection
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Solution Overview
Problem
Existing downhole inspection tools face challenges in capturing a 360° view of a pipe's internal surface with low distortion, as current solutions either result in image distortion, require time-consuming image stitching, or are impractical for deployment on slickline cables due to motor failure risks and limited memory capabilities.
Innovation Solution
An inspection assembly featuring a circumferential array of sideview cameras with negative meniscus viewport elements made of sapphire, combined with angled light sources for even illumination, allowing for a 360° view without the need for camera rotation and enabling real-time image capture or storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single sideview camera is used to capture 360° view, then the device complexity is reduced, but the reliability decreases due to motor failure risk and the productivity decreases due to slow image capture process
Solution Approach 1:
The inspection tool divides the single camera function into multiple cameras arranged circumferentially around the tool body. Each camera captures a specific sector of the internal surface, eliminating the need for rotation while achieving complete 360° coverage through simultaneous multi-point imaging.
Solution Approach 2:
The solution transitions from a single-point sequential imaging approach to a multi-point parallel imaging approach by distributing cameras around the circumference. This spatial arrangement in another dimension enables simultaneous capture of the entire circumference without mechanical movement.
2Productivity
If multiple cameras are arranged around the circumference to capture 360° view, then the productivity is improved by capturing full view simultaneously, but the device complexity increases and manufacturing precision becomes more difficult to achieve
Solution Approach 1:
Multiple identical camera modules are used, each performing the same function of capturing images of the internal surface. This modular approach simplifies the overall design by repeating a standardized unit rather than creating a complex single-camera system with multiple functions.
Solution Approach 2:
The patent combines multiple camera fields of view into a single composite 360° image through image stitching. The individual camera images are merged to create a complete circumferential view, achieving full coverage while maintaining a relatively simple camera arrangement.
3Measurement precision
If viewport elements with specific curvature are used, then the measurement precision is improved by reducing image distortion, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise curvature parameters for the viewport elements, with the internal surface having a radius of curvature between 2mm and 10mm. By controlling this geometric parameter, the optical path is optimized to minimize distortion of the captured images while maintaining manufacturability.
Solution Approach 2:
The viewport elements are designed with curved surfaces rather than flat surfaces. The concave internal surface and convex external surface create a meniscus lens effect that compensates for optical distortion, improving image quality while the curvature can be manufactured within standard tolerances.
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 a compact, high-resolution 360° view with reduced distortion, suitable for use in high-pressure and temperature environments, and allows for real-time image transmission or storage, enhancing the practicality of downhole inspections.
Implementation Method 1
each of the viewport elements has a concave internal surface, closer to the camera, and a convex external surface, further from the camera... 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
Data Source
Figure 1~3
Figure 4~6
AI summary
This invention relates to inspection assemblies that include one or more sideview cameras for capturing images of an interior surface of a pipe or conduit. This invention also relates to downhole inspection tools including such inspection assemblies. An inspection assembly (110) comprises an elongate housing (116), a sideview camera within the housing (116) and arranged to capture an image of a region within a field of view external to the housing (116), and a viewport element (114) mounted in the housing (116) and located such that light is transmitted through the viewport element (114) and into said sideview camera, wherein the viewport element (114) has a concave internal surface (156), closer to the camera, and a convex external surface (158), further from the camera, and wherein the centre of the radius of curvature of the internal surface (156) is closer to the viewport element (114) than the centre of the radius of curvature of the external surface (158).