Indirect Time-of-Flight Distance Measurement Using Multi-Frequency Deviation Coefficients
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Solution Overview
Problem
Indirect time-of-flight optical detection systems face challenges in accurately determining distances due to the limitations of maximum measurable distance with increasing modulation frequency, leading to high noise and standard deviations when using multiple frequencies for consistency tests.
Innovation Solution
A method and system that determine the real distance by calculating an initial deviation coefficient between reported distances, incrementing the smallest distance, and repeating until all distances exceed a common reference, using a processing circuit to minimize noise and standard deviations by averaging the current distances with the smallest deviation coefficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the frequency of modulated optical light radiation is increased to improve measurement repeatability, then measurement precision is improved, but the maximum measurable distance decreases
Solution Approach 1:
The patent segments the measurement process into multiple frequency measurements, where each frequency provides a reported distance valid up to its own maximum measurable distance. By dividing the overall measurement task into multiple frequency-based sub-measurements, the system can accurately measure both near and far objects using different frequencies, thus resolving the contradiction between precision and range.
Solution Approach 2:
The patent changes the modulation frequency parameter to adapt to different measurement ranges. By selecting appropriate frequencies based on the expected distance range, the system optimizes measurement precision for each specific case while maintaining the ability to measure at various distances, thus resolving the fixed trade-off between precision and maximum distance.
2Length of stationary object
If multiple radiation frequencies are used to extend maximum measurable distance, then the measurable distance range is improved, but device complexity and measurement reliability deteriorate due to inconsistent reported distances
Solution Approach 1:
The patent implements a feedback mechanism where reported distances from multiple frequencies are compared and validated against consistency criteria. The system uses the known relationship between frequencies and maximum measurable distances to verify whether reported distances are consistent, automatically identifying and correcting measurements that exceed their frequency's valid range, thus reducing complexity while maintaining reliability.
Solution Approach 2:
The patent establishes a unified reference framework where all reported distances from different frequencies are evaluated against a common consistency criterion. By creating this equipotential measurement baseline, the system simplifies the integration of multi-frequency data, allowing straightforward comparison and validation without complex frequency-specific processing, thus reducing overall device complexity.
3Length of stationary object
If multiple radiation frequencies are used to extend maximum measurable distance, then the measurable distance range is improved, but measurement reliability deteriorates due to environmental noise and standard deviations
Solution Approach 1:
The patent uses feedback validation where each reported distance is checked against the expected maximum measurable distance for its frequency. Measurements that fall outside their valid range are identified as unreliable and excluded from the final result, thus maintaining high measurement reliability even when using multiple frequencies to extend the overall measurable distance range.
Solution Approach 2:
The patent converts the potential harm of frequency mismatches and environmental noise into a benefit by using the known frequency-distance relationship as a validation criterion. What could be harmful (inconsistent measurements from multiple frequencies) is transformed into a useful filtering mechanism that automatically identifies and eliminates unreliable measurements, thus improving overall reliability.
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 systematically determines the real distance while reducing noise and standard deviations, allowing for accurate distance measurement across multiple modulation frequencies.
Implementation Method 1
indirectly measures the distance separating an object situated in the detection field and the so-called 'iToF' system via a measurement of phase shift of the optical signal received after the reflection on the object relative to the emitted optical light radiation
Implementation Method 2
indirect time-of-flight ('iToF') optical detection system
Data Source
AI summary
A method, for determining the real distance separating an object and an optical detection system, includes, from several so-called reported distances respectively less than or equal to individual reference distances dependent respectively on modulation frequencies: in a first step, determining an initial deviation coefficient between the reported distances and incrementing the smallest of the reported distances with the corresponding individual reference distance; then in a second step, determining a current deviation coefficient between the current distances obtained in the preceding step and incrementing the smallest of the current distances with the corresponding individual reference distance; and in a third step, repeating the second step until all the current distances exceed a common reference distance greater than the individual reference distances.