Submerged Surface Laser Ranging Refraction Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Accurately locating and measuring structural anomalies in submerged structures or objects is a laborious and challenging task, especially in underwater environments, due to the difficulties of human-based inspections and the limitations of existing non-destructive inspection techniques.
Innovation Solution
A system and method using a remotely operated submersible platform equipped with a local positioning system, including a pan-tilt mechanism, camera, and laser range meter within a liquid-tight pressure vessel, which compensates for light refraction in the liquid medium to provide accurate three-dimensional coordinate measurements of submerged surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If human-based inspections are used to locate and measure structural anomalies in submerged structures, then inspection data can be obtained, but the process becomes time-consuming, expensive, and difficult to perform
Solution Approach 1:
The patent replaces manual human-based inspection methods with an automated optical measurement system consisting of a laser range meter, camera, and pan-tilt mechanism mounted on a submersible platform. The laser range meter automatically measures distances to anomaly points while the camera captures images, and the pan-tilt mechanism enables automated scanning across the submerged structure surface, eliminating the need for manual measurement and significantly reducing inspection time while maintaining measurement precision
Solution Approach 2:
The measurement system performs self-positioning and self-measurement functions by using the laser range meter to automatically determine distances from the platform to various points on the submerged structure. The system independently calculates three-dimensional coordinates of anomaly points by combining laser range data with platform position information, without requiring external assistance or manual intervention, thereby reducing both time and cost
2Ease of operation
If existing non-destructive inspection techniques are used via unmanned submersible vehicles, then safety is improved and equipment cost is reduced, but determining the location and size of anomalies becomes challenging
Solution Approach 1:
The patent introduces a laser range meter as an intermediary measurement tool between the submersible platform and the submerged structure. The laser range meter emits laser beams that reflect off the structure surface and return to the meter, providing precise distance measurements. This intermediary device enables accurate anomaly location determination without requiring the operator to be in direct contact with the submerged structure, maintaining safety while solving the measurement difficulty
Solution Approach 2:
The system replaces traditional visual inspection and manual measurement methods with an optical-based laser ranging system. The laser range meter automatically calculates distances by measuring the time of flight of laser pulses, and the computer system processes this data to determine precise three-dimensional coordinates of anomalies, significantly improving the ease of detecting and measuring anomaly locations compared to conventional methods
3Adaptability or versatility
If a liquid-tight pressure vessel with optically transparent enclosure is used to house the laser range meter, then the system can operate in submerged environments, but light refraction at the enclosure interfaces affects measurement accuracy
Solution Approach 1:
The patent incorporates a refractive index sensor that continuously monitors the refractive index of the liquid surrounding the optically transparent enclosure. This feedback information is used by the computer system to calculate and compensate for the refraction effects on laser light paths. By adjusting the measurement calculations based on real-time refractive index data, the system maintains high measurement precision despite operating through the enclosure interfaces in submerged environments
Solution Approach 2:
The system dynamically adjusts measurement parameters by using the refractive index sensor to detect changes in the liquid's optical properties. When the refractive index changes (e.g., due to different water conditions), the computer system modifies the calculation parameters for laser beam path compensation accordingly. This parameter adjustment enables the system to maintain measurement accuracy across varying underwater environmental conditions
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
Enables efficient and accurate correlation of inspection data with anomaly positions, allowing for precise measurement and location of anomalies in submerged environments, overcoming the limitations of existing methods by providing continuous and discrete three-dimensional coordinate measurements.
Implementation Method 1
a laser range meter affixed to the camera; the laser range meter and optically transparent enclosure are configured to reduce refraction of laser light at the enclosure interfaces
Implementation Method 2
the laser range meter and optically transparent enclosure are configured to reduce refraction of laser light at the enclosure interfaces; a computer is configured to control the processing of measurement data to compensate for the effects of the liquid medium on the speed of light
Implementation Method 3
a pan-tilt mechanism coupled to the platform and disposed inside the liquid-tight pressure vessel; the pan-tilt mechanism is capable of angle measurement and motion control
Implementation Method 4
a refractive index sensor (a.k.a. refractometer) coupled to and disposed outside the liquid-tight pressure vessel; the speed of light of the liquid is determined using a refractive index sensor that measures the index of refraction in the liquid
Implementation Method 5
a camera mounted to the pan-tilt mechanism
Data Source
AI summary
Apparatus and methods for measuring a position of a point on a submerged surface. The apparatus includes: a platform; a liquid-tight pressure vessel fixedly coupled to the platform, wherein the liquid-tight pressure vessel is formed in part by an optically transparent enclosure; a pan-tilt mechanism coupled to the platform and disposed inside the liquid-tight pressure vessel; a camera mounted to the pan-tilt mechanism; a laser range meter affixed to the camera; and a refractive index sensor coupled to and disposed outside the liquid-tight pressure vessel. In accordance with one proposed implementation, the optically transparent enclosure is spherical, the pan-tilt mechanism has a pan axis and a tilt axis that intersect at a center of the optically transparent enclosure, and the laser range meter is located to emit a laser beam that is perpendicular to the optically transparent enclosure.