Dynamic Light Emission Control for ToF Sensor Power Optimization
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Solution Overview
Problem
Existing time gating ToF distance image sensors face challenges in reducing power consumption due to the need for multiple measurements, leading to excess power consumption and inefficiency.
Innovation Solution
A photoelectric conversion device and method that adjust the number of laser pulses emitted based on the distance, using a control unit to manage the light source and detection units, and a processing unit to calculate logical sums of detection signals, thereby optimizing power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple measurements are performed in each gate window, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic adjustment of the number of light emissions based on detection results. The system performs a predetermined number of light emissions initially, then dynamically decides whether to perform additional emissions based on whether the detection result meets a predetermined criterion. This dynamic approach allows the system to reduce power consumption by performing fewer emissions when the target is clearly detected, while maintaining measurement precision when needed.
Solution Approach 2:
The patent changes the parameter of light emission count based on detection outcomes. The system adjusts the number of pulsed light emissions dynamically - performing a base number of emissions (e.g., 100 pulses) and conditionally performing additional emissions (e.g., another 100 pulses) only when necessary. This parameter adjustment resolves the contradiction by adapting the emission count to actual measurement needs rather than always performing maximum measurements.
2Measurement precision
If the number of light emissions is increased, then detection accuracy is improved, but frame rate decreases
Solution Approach 1:
The system dynamically adjusts the number of light emissions based on intermediate detection results. After performing an initial set of light emissions and evaluating the detection result against a predetermined criterion, the system decides whether to perform additional emissions. This dynamic decision-making process allows the system to maintain high detection accuracy when needed while improving frame rate by reducing emissions when the target is easily detectable.
Solution Approach 2:
The patent implements a two-stage emission approach where a base number of emissions is always performed, and additional emissions are performed only partially (conditionally) when needed. This partial action principle allows the system to achieve sufficient detection accuracy for most cases with fewer emissions, reserving additional emissions for challenging detection scenarios, thereby improving overall frame rate.
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 proposed solution effectively reduces power consumption by adjusting the light emission number according to the measurement distance, improving the frame rate of distance images and stabilizing ranging operations, especially at shorter distances.
Implementation Method 1
a light detection unit including a photoelectric conversion element
Data Source
AI summary
A conversion device includes a light detection unit including a photoelectric conversion element, a control unit that controls the light detection unit and a light source device, and a processing unit that processes a signal indicating a detection result of incident light to the light detection unit. The control unit controls the light source device so that pulsed light is emitted from the light source device, and controls the light detection unit so as to detect light incident on the light detection unit in a time window corresponding to a certain distance. The processing unit outputs a light detection frame constituted by a 1-bit signal by calculating a logical sum of signals that are output from the light detection unit and indicate detection results, the number of the signals corresponding to a light emission number. The light emission number varies depending on distances to be measured.