Laser Mark Map Correction for Indoor Mobile Localization
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Solution Overview
Problem
Existing localization and mapping techniques for mobile electronic devices, such as GPS and bar code positioning, are impractical in indoor environments due to signal issues and environmental limitations, making simultaneous localization and mapping (SLAM) challenging in unknown spaces.
Innovation Solution
A method and apparatus using laser devices to construct and correct maps, where a mobile electronic device with a camera and encoder traverses a space, recording obstacle coordinates and projecting marks with unique encoding information to create a map, and later corrects the map using pixel position calculations to account for deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GPS positioning is used for mobile electronic devices, then outdoor localization can be achieved, but it cannot be applied in indoor environments due to signal problems
Solution Approach 1:
The patent introduces laser devices as intermediary objects that project marks onto the environment. These marks serve as mediators between the mobile electronic device and the environment, enabling localization through mark recognition rather than direct GPS signal reception. The laser-projected marks create artificial reference points that the device can detect and use for positioning in GPS-denied indoor environments.
Solution Approach 2:
The patent replaces the GPS satellite-based electromagnetic signal system with a local laser-based optical marking system. Instead of relying on external satellite signals that penetrate poorly indoors, the system uses locally generated laser marks that are easily detectable by the device's camera, achieving reliable indoor localization through a different physical mechanism.
2Ease of operation
If bar code positioning mode is used, then positioning can be implemented, but it is limited in usage occasions due to bar codes being easily polluted and can't be read
Solution Approach 1:
The patent replaces static bar code markers with dynamic laser-projected marks. Unlike printed bar codes that can be obscured by pollution or damage, laser marks are generated on-demand and can be continuously updated or re-projected, eliminating the reliability issues associated with physical bar code degradation while maintaining the simplicity of marker-based positioning.
Solution Approach 2:
The system transitions from static bar codes to dynamic laser projections. The laser marks can be adjusted, re-projected, or updated in real-time based on environmental conditions, providing a flexible and reliable positioning solution that adapts to various usage scenarios unlike fixed bar codes.
3Adaptability or versatility
If simultaneous localization and mapping (SLAM) is used in unknown environments, then mapping can be constructed without prior knowledge, but it is difficult or even impossible to obtain the map in advance
Solution Approach 1:
The patent places laser devices in advance at specific positions within the environment to project marks before the mobile device arrives. This preliminary setup of reference marks enables the mobile device to perform accurate localization and mapping without needing to build the map incrementally through SLAM, significantly improving map accuracy while maintaining adaptability to unknown environments.
Solution Approach 2:
The laser-projected marks serve as intermediaries that bridge the gap between unknown environments and accurate mapping. These marks provide known reference points that the mobile device can use to accurately determine its position and construct the map, eliminating the accumulation of errors inherent in traditional SLAM approaches.
4Productivity
If traditional SLAM methods are used with gyroscopes and wheel encoders, then localization can be achieved, but map errors occur due to gyroscope drifting or wheel slipping
Solution Approach 1:
The patent implements a feedback mechanism where the mobile device recognizes laser-projected marks in the environment and uses their known positions to correct localization errors. This feedback loop continuously validates and adjusts the device's estimated position against the actual mark locations, eliminating cumulative drift errors from gyroscopes and wheel encoders while maintaining real-time mapping capability.
Solution Approach 2:
The laser marks act as intermediary reference points that provide ground truth position information. By comparing the device's calculated position (from SLAM) against the known mark positions, the system can identify and correct errors, serving as a mediator that reconciles the conflicting information from inertial sensors and environmental features.
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 enables accurate, real-time mapping and navigation in indoor environments with high precision, simplicity, and low cost, while avoiding map errors caused by gyroscope drifting or wheel slipping.
Implementation Method 1
the color of the object is determined by the type of light it reflects, the white object can reflect the visible light of various wavelengths
Implementation Method 2
the photoelectric converter converts reflected light signal into the corresponding electrical signal on the basis of different strength of the reflected light signal
Data Source
AI summary
A method for map constructing, applicable for real-time mapping of a to-be-localized area provided with at least one laser device, includes taking a position of a mobile electronic as a coordinate origin of a map coordinate system, when a center of a mark projected by a first laser device coincides with central point of CCD/CMOS; moving the mobile electronic device with the coordinate origin as a starting point to traverse the entire to-be-localized area, calculating and recording coordinate values of a position of one of obstacles each time when it is detected by the mobile electronic device; and constructing a map based on recorded information of mark and corresponding coordinate values and the coordinate values of the position of each said obstacle after the traversing process is finished.