3D ToF Imaging With Spot-Position Phase Disambiguation
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Solution Overview
Problem
Existing Time-of-Flight (ToF) cameras face phase ambiguity issues, leading to distance ambiguity in depth measurements, which current methods struggle to resolve efficiently without increasing computational load or introducing motion artifacts.
Innovation Solution
A method and device using spot disparity to disambiguate phase delays by comparing actual spot positions to reference positions, leveraging a spot illuminator and image sensor baseline distance to determine unambiguous phase delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase unwrapping techniques are used to resolve distance ambiguity, then measurement precision is improved, but device complexity and computational load increase
Solution Approach 1:
The patent introduces spot position information as an intermediary element that mediates between the ambiguous phase measurement and the true depth value. By capturing the position of illuminated spots on the object surface and comparing it with reference positions, the system obtains additional constraints that help resolve phase ambiguity without requiring complex phase unwrapping algorithms. This intermediary spatial information simplifies the computational process while maintaining measurement precision.
2Measurement precision
If multiple frequency measurements are used to extend unambiguous range, then measurement precision is improved, but productivity decreases due to increased measurement time
Solution Approach 1:
The patent transitions from a one-dimensional frequency-based approach to a two-dimensional solution by incorporating spatial spot position information. Instead of extending the unambiguous range through multiple frequency measurements that require sequential acquisition, the system uses the spatial dimension of spot positions to disambiguate phase measurements. This allows the unambiguous range to be extended while maintaining a single-frequency measurement, thus preserving frame rate and productivity.
3Measurement precision
If conventional phase disambiguation methods are used, then measurement precision is improved, but reliability decreases due to motion artifacts
Solution Approach 1:
The patent performs preliminary capture of spot positions on the object surface before phase measurement disambiguation. By establishing reference spot positions in advance and comparing them with measured positions, the system creates a spatial framework that remains valid even during object motion. This preliminary spatial characterization enables robust phase disambiguation that is insensitive to motion artifacts, improving reliability while maintaining precision.
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
Resolves phase ambiguity with reduced computational power, increased frame rate, and improved motion robustness by disambiguating phase delays based on spot displacement, enhancing depth measurement accuracy.
Implementation Method 1
A Time-of-Flight (ToF) camera is a range imaging camera system that determines the distance of objects by measuring the time of flight of a light signal between the camera and the object
Implementation Method 2
a pixel array that collects light reflected from the same region of interest
Implementation Method 3
an illumination unit that illuminates a region of interest with modulated light
Data Source
AI summary
An electronic device comprising circuitry configured to disambiguate a first phase delay obtained according to an indirect Time-of-Flight principle to obtain a second phase delay, wherein the circuitry is configured to disambiguate the first phase delay based on a captured spot position.