Time-of-flight Circuitry Gray Code Detection Pattern
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Solution Overview
Problem
Current time-of-flight systems face challenges such as high memory usage, noise in indirect ToF measurements, low signal-to-noise ratio, non-linearities, and increased power consumption, which affect accuracy and precision in distance determination.
Innovation Solution
The implementation of a time-of-flight circuitry that applies a set of detection time intervals with a predetermined detection pattern, encoded using Gray Code, to enhance the accuracy and efficiency of light detection events, thereby improving the signal-to-noise ratio and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional ToF measurement methods are used, then distance determination can be achieved, but memory usage increases and system size grows
Solution Approach 1:
The detection time interval is segmented into multiple sub-intervals, each associated with a specific demodulation frequency. This segmentation allows the system to encode distance information across multiple frequency components rather than using a single large memory structure, thereby reducing overall system size while maintaining measurement precision.
Solution Approach 2:
The patent introduces a frequency dimension by using multiple demodulation frequencies (e.g., 1st, 2nd, 4th harmonics) to encode distance information. This transforms the traditional single-frequency approach into a multi-dimensional frequency-space representation, enabling more efficient use of memory and reducing system complexity.
2Measurement precision
If indirect TOF measurement is used, then distance can be measured, but noise increases and signal-to-noise ratio decreases
Solution Approach 1:
The patent combines multiple demodulation frequencies (1st, 2nd, and 4th harmonics) into a unified detection scheme. By merging these frequency components and processing them together through the same detection circuitry, the system achieves better signal-to-noise ratio while maintaining the indirect TOF measurement capability.
Solution Approach 2:
The detection circuitry continuously processes signals across multiple frequency components without interruption. The continuous detection and processing of multi-frequency signals ensures that useful signal information is captured and processed without gaps, improving the signal-to-noise ratio compared to intermittent or single-frequency detection methods.
3Measurement precision
If multiple demodulation frequencies are used, then measurement uncertainty decreases, but power consumption increases
Solution Approach 1:
The system uses periodic demodulation signals at different frequencies (1st, 2nd, 4th harmonics) to encode distance information. By using periodic actions at multiple frequencies rather than continuous high-frequency signaling, the system achieves reduced measurement uncertainty while controlling power consumption through efficient periodic detection cycles.
Solution Approach 2:
The patent changes the frequency parameter by using multiple discrete frequency components (1st, 2nd, 4th harmonics) instead of a single continuous frequency. This parameter change allows the system to achieve better measurement precision through frequency diversity while managing power consumption by selecting optimal frequency combinations that minimize energy usage.
4Productivity
If conventional detection patterns are used, then light detection events can be recorded, but non-linearities affect accuracy
Solution Approach 1:
The detection pattern is made dynamic by adapting the demodulation frequencies based on the detection time interval. Different frequency components are selectively applied depending on the specific measurement conditions and time interval, allowing the system to compensate for non-linearities through dynamic frequency adjustment while maintaining high productivity in detection event recording.
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 enables more precise and efficient time-of-flight measurements by encoding detection events with Gray Code, reducing noise and non-linearities, and optimizing processing power, leading to improved distance determination accuracy and reduced system size.
Implementation Method 1
time-of-flight (ToF) systems for measuring a distance to a scene are known. In the case of dToF, a roundtrip delay of emitted light is measured and the distance is concluded 'directly' based on the roundtrip delay.
Implementation Method 2
a light pulse, e.g. a square light pulse of a predetermined frequency, may be emitted by a light source, which is reflected from a scene (e.g. an object) and received by the CAPD
Data Source
AI summary
The present disclosure generally pertains to time-of-flight circuitry configured to: apply a set of detection time intervals to at least one light detection event for determining a point of time of the at least one light detection event, wherein the set of detection time intervals has a predetermined detection pattern encoding predetermined points of time.