Time-of-Flight Camera Timing for Multi-Camera Interference
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Solution Overview
Problem
Existing time-of-flight systems experience interference when multiple cameras illuminate the same scene simultaneously, leading to inaccurate depth measurements due to crosstalk and interference between asynchronous cameras.
Innovation Solution
Implementing a time shift pattern for light pulse emission and detection in time-of-flight apparatus to ensure each camera has a unique time shift pattern, minimizing interference by synchronizing light source emission and detector activation with specific time shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple time-of-flight cameras illuminate the same region of interest simultaneously, then the coverage and measurement capability are improved, but interference and crosstalk between cameras increase
Solution Approach 1:
The patent applies periodic action by implementing time-division multiplexing where each camera emits light pulses in periodic cycles with unique time shifts. The control unit coordinates multiple cameras to emit light pulses at different time intervals within each period, allowing sequential illumination of the same region without simultaneous interference, thus maintaining measurement capability while eliminating crosstalk.
Solution Approach 2:
The patent implements preliminary action by having the control unit pre-assign unique time shift patterns to each camera before illumination begins. The control unit calculates and distributes timing information to each camera in advance, ensuring that cameras are synchronized and will not interfere with each other during the actual measurement process.
2Productivity
If multiple cameras perform distance measurements simultaneously, then productivity is improved, but measurement precision deteriorates due to interference
Solution Approach 1:
The system uses periodic time-division multiplexing where cameras take turns illuminating the scene in rapid succession. Each camera operates in periodic cycles with assigned time slots, allowing multiple cameras to collectively achieve high measurement throughput while maintaining individual camera precision by eliminating simultaneous interference.
Solution Approach 2:
The control unit dynamically assigns time shift patterns to cameras based on measurement requirements. The timing parameters can be adjusted in real-time to optimize both productivity and precision, allowing the system to adapt to different scene complexities and distance ranges while maintaining accurate measurements.
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
The solution effectively reduces interference, allowing accurate depth measurements by ensuring that each camera's photons are detected as distinct peaks, reducing noise and enhancing measurement precision.
Implementation Method 1
The distance can be determined, for example, based on the time-of-flight of the photons of the light source reflected in the region of interest
Data Source
AI summary
A time-of-flight apparatus has: a light source for emitting light pulses to a scene; a light detector for detecting light from the scene; and a control, the control being configured to: drive the light source to emit light pulses, based on a time shift pattern; and drive the light detector for detecting light in accordance with the time shift pattern.