Mobile 3D Surface Surveying With Structured Light Vehicles

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing three-dimensional surveying systems using mobile vehicles face challenges in accuracy and flexibility, particularly when surveying surfaces with limited visual features, as they rely on automatically detectable features in camera images, which can lead to inaccurate or incorrect results.

Innovation Solution

A system comprising a first mobile vehicle with a camera unit and a second mobile vehicle equipped with a light projection unit that emits a structured light pattern, allowing the camera unit to image and evaluate the pattern distorted by the surface topology, utilizing a simultaneous location and mapping algorithm to determine the surface topology and location, enhancing surveying accuracy and adaptability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If visual surveying algorithms rely on automatically detectable features in camera images, then the system can operate autonomously, but accuracy deteriorates when surveying surfaces with limited visual features

Engineering Contradiction:
Improveautonomous operationVSAvoidsurveying accuracy
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The patent introduces a light projection unit as an intermediary device that projects structured light patterns onto the target surface. This mediator creates artificial visual features that the camera can detect and use for accurate surveying, even when the natural surface lacks sufficient visual features for autonomous operation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Before the camera captures images for surveying, the light projection unit preliminarily modifies the surface appearance by projecting structured light patterns. This preliminary action ensures that when the camera images the surface, sufficient visual features are already present for accurate autonomous surveying

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If a single mobile vehicle carries both camera and light projection units, then device complexity is reduced, but flexibility and adaptability worsen

Engineering Contradiction:
Improvesystem structureVSAvoidsurveying flexibility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent divides the surveying system into separate mobile vehicles: one carrying the camera unit and another carrying the light projection unit. This segmentation allows each vehicle to be optimized for its specific function while maintaining overall system flexibility and adaptability to different surveying scenarios

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system achieves multi-functionality by having separate specialized vehicles that can be independently deployed and configured. The camera-bearing vehicle and light-projection vehicle can operate in various combinations and configurations, providing universal adaptability to different surveying environments and requirements

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If structured light patterns are projected onto surfaces, then surveying accuracy of optically uniform surfaces improves, but device complexity increases

Engineering Contradiction:
Improvesurveying accuracyVSAvoidsystem structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The light projection unit serves as an intermediary that adds structured light patterns to optically uniform surfaces. This mediator creates the necessary visual contrast and geometric features that enable accurate surveying without requiring complex modifications to the camera or processing systems

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system replaces the need for mechanically complex multi-camera setups or close-range positioning systems by using optical structured light projection. This substitution achieves high measurement precision through optical field manipulation rather than mechanical complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This approach improves the accuracy and flexibility of three-dimensional surveying by providing additional information through structured light patterns, resolving ambiguities and enhancing the ability to survey optically uniform surfaces, leading to more reliable and precise topographical data collection.

Implementation Method 1

a light projection unit built to emit a defined structured light pattern onto the surface

Methodology Applied
Scientific EffectLight: Light

Implementation Method 2

the camera unit of the first mobile vehicle at least partially images the structured light pattern projected from the second mobile vehicle onto the surface

Methodology Applied
Scientific EffectOptical distortion: Refraction

Data Source

PatentEP3168704B13D surveying of a surface by mobile vehicles
Publication Date: 2021.02.24 HEXAGON TECH CENT GMBH
  • EP3168704B1 patent drawingFigure 1
  • EP3168704B1 patent drawingFigure 2
  • EP3168704B1 patent drawingFigure 3

AI summary

The present invention relates to a system and method for three dimensional surveying of a surface. It comprises at least a first mobile vehicle with at least one camera unit having its field of view at least partially directed towards the surface for imaging the surface. It also comprises a computer-vision unit built to execute a visual surveying algorithm based on images from the camera unit for determining a topology of the surface and/or a location relative to the surface. There is also at least a second mobile vehicle, comprising a light projection unit built to emit a structured light pattern onto the surface. The camera unit of the first mobile vehicle at least partially images the structured light pattern projected from the second mobile vehicle onto the surface and the computer-vision unit executes the visual surveying algorithm at least partially with an evaluation of the first mobile vehicle's images taken with the structured light pattern emitted from the second mobile vehicle.