Structured Light 3D Point Cloud Generation for Underwater Surveys
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Solution Overview
Problem
Current methods for obtaining 3D point clouds in underwater surveys are inefficient, requiring expensive technology and suffering from slow acquisition times and deployment complications, especially when used on moving underwater vehicles.
Innovation Solution
A method utilizing a system with camera modules and structured light sources to project a two-dimensional array of points onto the underwater scene, capturing images from multiple positions to calculate 3D coordinates, and optionally combining with white light images for color visualization, allowing for high-speed, real-time 3D point cloud generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If known methods including time of flight measurements and laser line scanning are used, then 3D data can be obtained, but the technology is expensive and complex
Solution Approach 1:
The patent uses a camera to capture images of structured light patterns projected onto the scene, creating a visual copy of the 3D information. Instead of using complex time-of-flight sensors or laser scanners, the system projects known light patterns and captures their deformation by scene surfaces, then computationally reconstructs 3D coordinates from these 2D images. This copying approach simplifies the hardware while maintaining measurement capability.
Solution Approach 2:
The patent replaces mechanical laser scanning systems and time-of-flight measurement devices with an optical projection and imaging system. Instead of using mechanical moving parts to scan the scene or complex electronic timing circuits to measure light travel time, the system uses structured light projection combined with standard camera imaging and computational geometry to achieve 3D reconstruction.
2Measurement precision
If known methods including time of flight measurements and laser line scanning are used, then 3D data can be obtained, but the acquisition time is slow
Solution Approach 1:
The patent uses periodic projection of structured light patterns across the scene. By projecting a sequence of known 2D point arrays at different positions and capturing images for each position, the system systematically builds up 3D point cloud data. This periodic action allows for complete scene coverage while maintaining rapid acquisition, as each projected pattern can be captured in a single camera exposure rather than requiring sequential point-by-point scanning.
Solution Approach 2:
The patent transforms the 3D measurement problem into a 2D imaging problem by projecting structured light patterns and capturing them with a 2D camera sensor. The third dimension (depth) is recovered through computational analysis of the known projected pattern deformation in the 2D image plane. This dimensionality change allows parallel capture of multiple depth points simultaneously rather than sequential measurement, dramatically reducing acquisition time.
3Productivity
If high speed 3D real time point cloud generation is achieved on moving underwater vehicles, then survey efficiency improves, but the technology becomes more demanding
Solution Approach 1:
The patent uses a camera module that serves multiple functions: it captures images for 3D reconstruction, provides visual feedback for navigation, and can potentially be used for other survey tasks. The structured light projection system is integrated with the camera to form a unified measurement platform that can operate on moving underwater vehicles. This multi-functionality reduces the need for separate specialized equipment while maintaining high survey efficiency.
Solution Approach 2:
The system uses the camera's own imaging capability to capture the projected structured light patterns, rather than requiring separate sensors. The processing module uses standard image processing techniques to extract 3D information from the captured images, leveraging the camera's inherent computational capabilities. This self-service approach allows the system to achieve real-time 3D generation without adding complex external measurement devices.
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 high-resolution, real-time 3D point cloud generation on moving underwater vehicles, improving survey efficiency and reducing costs by simplifying the technology and increasing acquisition speed.
Implementation Method 1
each of the at least one camera module capturing an image of the projected array in the scene from first and second positions, such that there is a first point image and second point image; analysing the images to identify the location of each projected point within each point image; for each projected point in the captured point images, correlating the location of the point between the first and second point images to calculate the distance to the point from the at least one camera module
Implementation Method 2
a time-of-flight laser ranging device, a beam adjustor, a camera module and a controller, the method comprising: the time-of-flight laser ranging device measuring the range to a point in the scene by projecting a laser beam onto that point
Data Source
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AI summary
Provided is a method for generating a 3D point cloud and colour visualisation of an underwater scene, the point cloud comprising a set of (x, y, z) coordinates relating to points in the scene, the method operating in a system comprising at least one camera module, at least one structured light source, and a processing module, each of the at least one camera module being directed at the scene and having substantially the same overlapped field of view.