TOF Distance Measuring Apparatus Multipath Error Correction
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Solution Overview
Problem
Existing distance measuring apparatus using the Time of Flight (TOF) method face significant processing load and cost increases due to complex correction methods for multipath phenomenon, which result in distance errors, especially in environments with highly reflective materials, and do not adequately account for varying measured distances.
Innovation Solution
The apparatus identifies equations of planes in the measurement space, compares them with measured distances, and calculates correcting values to correct distance errors, reducing processing load and improving accuracy by using specific reference points with minimal multipath influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex correction methods are used to correct distance errors caused by multipath phenomenon, then distance measurement accuracy is improved, but device complexity and processing load increase
Solution Approach 1:
The patent changes the parameter of correction approach from complex temporal pulse comparison to simple plane equation-based spatial correction. By modeling walls and floors as planes with simple equations and using straightforward coordinate substitution, the system achieves effective multipath correction without complex processing
Solution Approach 2:
The patent replaces expensive, complex correction algorithms with simple, computationally inexpensive plane equations. The plane equations act as lightweight correction models that can be easily calculated and applied, significantly reducing processing load while maintaining correction effectiveness
2Measurement precision
If complex correction methods are used to correct distance errors, then distance measurement accuracy is improved, but processing load increases
Solution Approach 1:
The patent transforms the correction problem from temporal pulse analysis to spatial plane equation evaluation. This parameter change reduces computational complexity from comparing complex temporal variations to simple coordinate substitution in plane equations, significantly lowering processing load
Solution Approach 2:
The patent segments the correction task into simple, independent plane equation evaluations for each wall and floor surface. Instead of processing the entire multipath phenomenon as one complex problem, it divides correction into multiple simple plane-based calculations that can be performed efficiently and independently
3Device complexity
If a uniform correcting coefficient is used for all measured distances, then device complexity is reduced, but measurement precision deteriorates because the correcting coefficient should vary with measured distance
Solution Approach 1:
The patent applies local quality by making the correction specific to each spatial location and measured distance. Instead of a uniform correcting coefficient, it calculates corrections based on the specific plane equations and coordinates of each measurement point, allowing the correction to adapt locally to the actual multipath conditions at each distance
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 significantly reduces processing load and accurately corrects distance errors across different measured distances, enhancing the precision of distance measurements in environments with multipath interference.
Implementation Method 1
a light emitter 11 that emits irradiated light toward a target object 3
Implementation Method 2
an optical receiver 12 that detects reflected light reflected from the target object 3
Implementation Method 3
measures a duration (optical path length) from when irradiated light is emitted from a light source, which is reflected at a target object, to when the reflected light returns to an optical receiver
Data Source
AI summary
An objective of the present disclosure is to easily and precisely correct a distance error caused by multipath phenomenon in a distance measuring apparatus using TOF method. A distance measuring apparatus according to the present disclosure identifies an equation of plane that approximates a plane in a space where a target object exists, compares the equation of plane with a measured distance of the place, thereby calculating a correcting value for correcting a measured distance.