Time-of-Flight Light Event Detection Circuitry for Ambient Noise Reduction
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Solution Overview
Problem
Current time-of-flight (ToF) cameras face challenges in achieving high resolution and signal-to-noise ratio (SNR) while managing high ambient light conditions, leading to noise and increased power consumption.
Innovation Solution
The proposed solution involves time-of-flight light event detection circuitry that operates in both macropixel and window modes. In the macropixel mode, light events are determined for two predetermined time periods on two light detection elements, and in the window mode, a third time period is determined based on the macropixel mode for precise light event detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous monitoring of all light detection elements is performed, then complete light event detection is achieved, but power consumption increases
Solution Approach 1:
The system dynamically switches between macropixel mode and window mode based on detection needs. In macropixel mode, all light detection elements are monitored; in window mode, only selected elements within a specific time window are monitored, reducing power consumption while maintaining detection effectiveness
Solution Approach 2:
Instead of continuously monitoring all light detection elements, the system performs partial monitoring by focusing only on relevant time periods and selected light detection elements in window mode, achieving sufficient detection with reduced energy expenditure
2Reliability
If detection covers all time periods, then no light events are missed, but ambient noise increases
Solution Approach 1:
The system extracts and focuses detection efforts on the most relevant time periods where actual light events are expected to occur. By excluding irrelevant time periods from monitoring, ambient noise from those periods is naturally filtered out while maintaining detection of genuine light events
Solution Approach 2:
The system applies different detection strategies to different time periods: full monitoring in macropixel mode for comprehensive coverage, and focused windowed monitoring for specific time periods where light events are most likely to occur, thereby reducing ambient noise impact
3Measurement precision
If spatial resolution is increased, then detection precision is improved, but system complexity increases
Solution Approach 1:
The system segments the detection process into two distinct modes: macropixel mode for broad coverage and window mode for focused high-resolution measurement. This segmentation allows the system to achieve high spatial resolution when needed without permanently maintaining the complexity associated with continuous high-resolution monitoring
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 enhances the spatial resolution, reduces ambient noise, and conserves power by focusing detection on the most relevant time periods, thereby improving the overall performance of ToF cameras.
Implementation Method 1
In dToF, the distance is directly measured by measuring a time of flight which emitted light needs to return to the camera after reflection at a scene
Data Source
AI summary
The present disclosure generally pertains to time-of-flight light event detection circuitry configured to: determine, in a macropixel mode, for a first frame for a first predetermined time period, light events of light being incident on a first light detection element; determine, in the macropixel mode, for the first frame for a second predetermined time period, light events of light being incident on a second light detection element; and determine, in a window mode, based on the macropixel mode, for a second frame after the resulting first frame, a third time period, in which light events are to be detected.