Time-of-Flight Imaging Apparatus Using Dual Modulation Frequencies
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Solution Overview
Problem
Current time-of-flight imaging technologies are cost-intensive and power-consumptive due to high modulation frequencies, limiting measurement ranges and requiring multiple distance measurements for full depth imaging, while settings for acquiring confidence often result in higher energy consumption and reduced measurement ranges.
Innovation Solution
A time-of-flight imaging apparatus and method that acquire coarse and precise depth data using different modulation frequencies in coarse and precise imaging modes, respectively, to determine distances, allowing for a combination of data to minimize measurement errors and maximize confidence, with the option to switch between imaging modes based on power availability and requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high modulation frequency is used for distance measurement, then measurement precision is improved, but energy consumption increases and measurement range is reduced
Solution Approach 1:
The patent divides depth imaging into two distinct modes: coarse imaging mode using high modulation frequency for precise distance measurement, and precise imaging mode using low modulation frequency for extended measurement range. This segmentation allows the system to use high frequency only when necessary for precision, rather than continuously, thereby reducing overall energy consumption while maintaining measurement accuracy when needed.
Solution Approach 2:
The patent dynamically switches between coarse and precise imaging modes based on confidence determination. When the confidence of distance measurement from coarse mode exceeds a threshold, the system remains in coarse mode for energy efficiency. When confidence is insufficient, it transitions to precise mode to ensure accurate depth data, creating a dynamic adaptation mechanism that optimizes energy usage based on real-time measurement quality.
2Measurement precision
If high modulation frequency is used for distance measurement, then measurement precision is improved, but measurement range is reduced
Solution Approach 1:
The patent segments the measurement task into two frequency domains: high modulation frequency for precise short-range measurement and low modulation frequency for extended range measurement. By acquiring both coarse depth data (high frequency) and precise depth data (low frequency) and combining them, the system achieves both extended measurement range and maintained precision, resolving the contradiction between range and precision.
3Use of energy by moving object
If low modulation frequency is used for confidence acquisition, then energy consumption is reduced, but measurement range is extended
Solution Approach 1:
The patent implements a dynamic confidence-based switching mechanism where the system initially operates in low-power coarse imaging mode to extend measurement range and reduce energy consumption. It then evaluates measurement confidence and dynamically transitions to high-precision precise imaging mode only when confidence thresholds are not met, ensuring measurement precision is maintained while minimizing energy consumption during normal operation.
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 reduces energy consumption, extends measurement ranges, and allows for more precise distance determination by alternating between coarse and precise imaging modes, optimizing power usage and measurement accuracy.
Implementation Method 1
time-of-flight (ToF) devices are known, for example for imaging or creating depth maps of a scene... or to measure a distance, in general. It can be distinguished between direct ToF (dToF) and indirect ToF (iToF) for measuring a distance either by measuring the run-time of emitted and reflected light (dToF) or by measuring one or more phase-shifts of emitted and reflected light (iToF)
Data Source
AI summary
The present disclosure generally pertains to a time-of-flight imaging apparatus having cir-cuitry, configured to: acquire, in a coarse imaging mode, coarse depth data; acquire, in a precise imaging mode, precise depth data; and determine a distance to a scene based on the coarse depth data and the precise depth data.