Time-of-Flight Distance Calculation for Multipath Reflection
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Solution Overview
Problem
Existing methods for distance determination using time-of-flight cameras are impaired by multipath effects, leading to inaccurate distance measurements due to signal reflections at different surfaces, and existing solutions do not provide a closed-form solution.
Innovation Solution
A method involving the transmission of light signals with different frequencies, determining values at these frequencies, and calculating distance information using complex numbers and polar representations to account for multiple reflection paths, employing analytical calculations without iterative methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If common distance determination methods are used, then the process is simple, but measurement precision deteriorates due to multipath effects
Solution Approach 1:
The patent changes the frequency parameter by transmitting light signals at multiple different frequencies (first frequency and second frequency). This allows the system to distinguish between direct and reflected light paths by analyzing how the phase shift varies with frequency, thereby resolving multipath effects and improving distance measurement accuracy without requiring complex iterative computations.
2Measurement precision
If iterative approximation methods are used to compensate for multipath effects, then measurement precision improves, but calculation time increases and closed-form solution is not provided
Solution Approach 1:
The patent replaces iterative numerical approximation methods with an analytical closed-form solution. By using multiple frequency measurements and deriving explicit mathematical expressions to calculate distance, the system eliminates the need for iterative computations, thereby reducing calculation time while maintaining high measurement precision in compensating for multipath effects.
3Measurement precision
If multiple frequencies are used to resolve multipath effects, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent segments the frequency spectrum by using distinct first and second frequencies for light signal transmission. This segmentation allows the system to separately analyze the phase shift characteristics at different frequencies, making it easier to identify and compensate for multipath effects through straightforward mathematical operations rather than complex unified processing.
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 and efficient distance determination in a closed form, providing reliable results despite multipath interference.
Implementation Method 1
The phase or amplitude information of emitted light signals after reflection is in particular evaluated in so doing... determining at least one piece of distance information for a three-dimensional image from at least two time-of-flight differences between light signals emitted by a light source of a time-of-flight camera and light signals received by an image sensor
Implementation Method 2
through scattering or reflection of the emitted light signals at at least one object
Implementation Method 3
through scattering or reflection of the emitted light signals at at least one object
Data Source
AI summary
The invention relates to a method of determining at least one piece of distance information for a three-dimensional image from at least two time-of-flight differences between light signals emitted by a light source of a time-of-flight camera and light signals received by an image sensor of the time-of-flight camera through scattering or reflection of the emitted light signals at at least one object.