Dynamic Frame Rate Control for TOF Distance Detection
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Solution Overview
Problem
In time-of-flight (TOF) distance measurement devices, particularly in mobile terminals like smartphones, the optimization of light-emitting elements for size reduction and power efficiency leads to decreased distance detection accuracy at long ranges due to reduced light emission and increased power consumption.
Innovation Solution
A distance detection device dynamically controls the frame rate of light pulses based on the calculated distance, adjusting the frequency of light emission to maintain detection accuracy without increasing power consumption, using a series of frames with at least one light pulse and two light sensors to accumulate electrical charge for precise distance calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the number of light-emitting elements is reduced for size reduction and power efficiency, then device size and power consumption are improved, but distance detection accuracy deteriorates at long ranges
Solution Approach 1:
The patent implements dynamic frame rate adjustment based on detected distance. When the target is far away, the frame rate is reduced to accumulate more electrical charge in the light receiver, thereby improving detection accuracy without increasing power consumption. This dynamic adaptation resolves the contradiction by optimizing performance parameters in real-time rather than using fixed configurations.
Solution Approach 2:
The system changes operational parameters (frame rate) based on detection conditions. By adjusting the frame rate according to distance, the system accumulates appropriate amounts of electrical charge for accurate detection at various ranges while maintaining power efficiency. This parameter adaptation allows the same hardware to achieve accurate long-range detection without requiring more light-emitting elements.
2Measurement precision
If the frame rate is increased to improve detection accuracy, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The frame rate is dynamically adjusted based on the detected distance to the target. When the target is far away, the frame rate is reduced to accumulate more electrical charge in the light receiver, improving detection accuracy without continuously consuming high power. This dynamic control resolves the contradiction by optimizing the frame rate parameter in real-time rather than using a fixed high frame rate.
Solution Approach 2:
The system changes the frame rate parameter according to detection conditions and distance. By adapting the frame rate to match the required detection accuracy for each scenario, the system avoids unnecessary power consumption while maintaining sufficient detection accuracy. This parameter adaptation allows accurate long-range detection without the continuous high power consumption that would result from maintaining a high fixed frame rate.
3Measurement precision
If the light emission frequency is increased to maintain detection accuracy at long ranges, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The system dynamically adjusts the frame rate based on distance detection results. When targets are detected at long ranges, the frame rate is reduced to accumulate more electrical charge in the light receiver, thereby improving detection accuracy without increasing light emission frequency or power consumption. This dynamic adaptation resolves the contradiction by optimizing detection parameters in real-time.
Solution Approach 2:
The frame rate parameter is changed according to the detected distance and detection requirements. By adapting the frame rate to match the specific detection scenario, the system achieves accurate long-range detection through optimized charge accumulation rather than by increasing light emission frequency, thus avoiding increased power consumption.
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 detection accuracy at varying distances while maintaining power efficiency by dynamically adjusting the frame rate and light emission frequency, effectively mitigating the degradation of accuracy at longer ranges without increasing power consumption.
Implementation Method 1
a light receiver configured to receive, for each frame in the series of frames, the at least one light pulse when the at least one light pulse is reflected from a target
Implementation Method 2
there exists a TOF system including a three-dimensional distance sensor that measures the flight time of light emitted from a light-emitting device and reflected from a target to a light-receiving device. The distance of the target relative to the emitter/receiver may be calculated based on the time of flight and known properties related to the speed of light.
Data Source
AI summary
A device including an emitter that transmits light in a series of frames, wherein each frame in the series includes at least one pulse. The device includes a receiver that receives, for each frame in the series, the at least one pulse reflected from a target, and generates, in response to receiving the at least one pulse in a current frame, an output for calculating a distance between the target and the device for the current frame. The device includes circuitry that calculates, for each frame in the series, the distance between the target and the device based on the receiver output. The circuitry dynamically controls a frame rate for each frame in the series based on the distance calculated in a frame immediately preceding the current frame, and controls the emitter such that the at least one pulse is emitted in the current frame at the calculated frame rate.