Markerless 6DOF Positional Tracking via Laser and Camera Fusion
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Solution Overview
Problem
Current positional tracking systems in construction jobsites face challenges in using multiple independent laser receivers to simultaneously calculate positions without communication with the laser transmitter, and existing algorithms are not robust enough to handle environments with transparent, shiny, or textureless objects, requiring large tracking markers and being computationally expensive.
Innovation Solution
A positional tracking system that includes a laser transmitter, control tracker, and layout indicator, utilizing photo diodes and inertial measurement units to calculate 6DOF positions of objects without markers, using modulated laser beams and camera vision to determine azimuthal and height positions, and allowing multiple users to mark locations simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional laser measuring systems are used with one laser receiver, then measurement accuracy is maintained, but productivity is reduced due to sequential point-by-point measurement requiring 5 minutes per location
Solution Approach 1:
The patent uses visual copying of natural scene features into digital images captured by cameras mounted on receivers. Multiple receivers simultaneously capture images of the same laser spot and shared visual features in the environment, creating duplicate measurement data streams that can be processed independently to determine positions of multiple receivers at once, eliminating sequential measurement requirements
Solution Approach 2:
The system makes each laser receiver multi-functional by equipping it with both laser detection capabilities and independent camera vision capabilities. Each receiver can simultaneously detect the laser spot position and capture environmental visual features, allowing multiple receivers to independently determine their own positions and contribute to a shared spatial understanding without requiring communication with the transmitter
2Reliability
If tracking markers are attached to objects for positional tracking, then tracking reliability is improved, but device complexity and ease of operation are reduced due to requirement of large markers and manual attachment
Solution Approach 1:
The patent extracts the tracking function from physical markers and relocates it to natural visual features in the environment. Instead of attaching markers to objects, the system identifies and tracks naturally occurring visual features (edges, corners, textures) that are already present in the construction environment, eliminating the need for marker attachment while maintaining tracking capability through computer vision algorithms
Solution Approach 2:
The system enables objects and the environment to serve their own tracking function through their inherent visual characteristics. Natural features in the construction site (building edges, floor patterns, wall textures) automatically provide tracking references without requiring external marker attachment, and the receivers independently extract and utilize these features for position determination
3Ease of operation
If natural image features are used instead of tracking markers, then ease of operation is improved, but measurement precision and reliability deteriorate in environments with transparent, shiny, or textureless objects
Solution Approach 1:
The patent merges multiple data sources and processing approaches: combining laser range data with camera image data, merging features from multiple receivers' viewpoints, and integrating results from multiple natural feature detection algorithms. This fusion compensates for the weaknesses of individual natural features (which may be transparent, shiny, or textureless) by providing redundant and complementary information that maintains precision across diverse construction environments
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 6DOF tracking of multiple objects and locations in construction jobsites, reducing the need for manual placement of laser receivers and improving robustness in diverse environments, allowing multiple users to mark locations simultaneously and reducing computational costs.
Implementation Method 1
a laser transmitter (110), a control tracker (200)... utilizing photo diodes and inertial measurement units to calculate 6DOF positions of objects without markers, using modulated laser beams
Implementation Method 2
utilizing photo diodes and inertial measurement units to calculate 6DOF positions
Implementation Method 3
utilizing photo diodes and inertial measurement units to calculate 6DOF positions of objects without markers
Implementation Method 4
using modulated laser beams and camera vision to determine azimuthal and height positions
Data Source
AI summary
A position tracking system has a laser transmitter, a control tracker and a layout indicator. The laser transmitter has a laser for emitting a laser beam, a controller controlling the laser, and a motor for rotating the emitted laser beam. The control tracker has a housing, at least two photo diodes disposed on the housing, and a laser assembly for generating a beam to be projected unto a surface. The layout indicator has a housing, and at least two photo diodes disposed on the housing. A network server communicates with at least one of the laser transmitter, the control tracker and the layout indicator.