Stereo Camera Laser Distance Estimation
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Solution Overview
Problem
Current distance measurement technologies in mobile robotic devices, such as infrared sensors and sonar systems, are either inaccurate or costly, while laser distance sensors are not suitable for day-to-day home use due to complexity and expense, necessitating a more reliable and affordable method for remote distance estimation.
Innovation Solution
A distance estimation system comprising a collimated laser light emitter and two image sensors positioned symmetrically on a baseplate, capturing overlapping fields of view to determine distance through image processing and comparison with a preconfigured table, utilizing computer vision technology to accurately measure distances to surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser distance sensors (LDS) are used for accurate distance measurement, then measurement precision is improved, but device complexity and cost increase making them unsuitable for day-to-day home use
Solution Approach 1:
The system divides the measurement function into multiple components: a laser emitter projects light to the target surface, while two separate image sensors capture the reflected light from different angles. This segmentation replaces the single complex LDS with simpler, more affordable components that collectively achieve accurate distance measurement through geometric calculation.
Solution Approach 2:
The patent replaces the traditional time-of-flight or triangulation laser distance sensor system with an optical projection and image capture system. Instead of using complex laser ranging electronics, the system uses a laser pointer combined with standard image sensors and computational geometry to achieve the same measurement function at lower cost and complexity.
2Device complexity
If infrared sensors are used for distance detection, then device cost is reduced, but measurement precision deteriorates due to low resolution and sensitivity to sunlight
Solution Approach 1:
The system uses a visible laser light source that projects a distinct light point onto the target surface. This visible projection allows the image sensors to clearly detect the light position even in various lighting conditions, overcoming the sunlight sensitivity issue of infrared sensors while maintaining low cost.
Solution Approach 2:
The patent introduces a visible laser projection as an intermediary between the measurement system and the target surface. This projection creates a clearly visible reference point that the image sensors can track accurately, serving as a mediator that enables precise distance measurement using simple, low-cost sensors.
3Measurement precision
If sonar systems are used for distance measurement, then measurement precision is improved under optimal conditions, but reliability deteriorates due to limited coverage, cross-talk, and sensitivity to environmental factors
Solution Approach 1:
The patent replaces the acoustic sonar system with an optical system using laser projection and image capture. This substitution eliminates all the reliability issues associated with sonar (cross-talk, ground bounce, sound-absorbing materials) while maintaining measurement accuracy, as light does not suffer from these acoustic interference problems.
Solution Approach 2:
The system converts the potential harm of environmental interference into a benefit by using visible light projection. The laser projection creates a distinct visual marker that can be easily distinguished from the background, and the geometric calculation method is immune to environmental factors that plague sonar systems, turning the optical approach into a more reliable solution.
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 solution provides a more accurate and reliable method for distance measurement, capable of estimating distances in various directions, overcoming the limitations of existing technologies by using a cost-effective system that can be mounted on a rotatable base for comprehensive coverage.
Implementation Method 1
a laser light emitter disposed on a baseplate emitting a collimated laser beam which projects a light point onto surfaces opposite the emitter
Implementation Method 2
two image sensors disposed symmetrically on the baseplate on either side of the laser light emitter... capturing the projections made by the laser light emitter
Data Source
AI summary
A distance estimation system comprised of a laser light emitter, two image sensors, and an image processor are positioned on a baseplate such that the fields of view of the image sensors overlap and contain the projections of an emitted collimated laser beam within a predetermined range of distances. The image sensors simultaneously capture images of the laser beam projections. The displacement of the laser beam projection from a first image taken by a first image sensor to a second image taken by a second image sensor is extracted by the image processor. The displacement is compared to a preconfigured table relating displacement distances with distances from the baseplate to projection surfaces to find an estimated distance of the baseplate from the projection surface at the time that the images were captured.