Dynamic Vision Sensor Leakage Current Compensation
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Solution Overview
Problem
Dynamic vision sensors face challenges in accurately measuring photocurrent at low illuminance and dark states due to interference from leakage currents, which affects the reliability and accuracy of light intensity detection.
Innovation Solution
The dynamic vision sensor employs a pixel array with first and second photoreceptors, alternately enabled to measure photocurrents, and processing circuitry to amplify log voltages and detect changes in light intensity, outputting event signals and determining pixel average photocurrent by calculating the difference between the photocurrents from these photoreceptors, thereby isolating and removing leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a dynamic vision sensor measures photocurrent at low illuminance, then light intensity detection capability is improved, but measurement precision deteriorates due to interference from leakage currents
Solution Approach 1:
The pixel array is divided into multiple photoreceptors, each independently measuring photocurrent. By segmenting the measurement function across multiple photoreceptors and using differential calculation, the patent isolates the signal from leakage current interference, enabling accurate measurement at low illuminance levels
Solution Approach 2:
The patent implements a feedback mechanism where the measured photocurrent values from multiple photoreceptors are used to calculate and compensate for leakage current effects. The processing circuitry uses the differential information from multiple measurements to adjust and refine the final photocurrent value, improving measurement precision at low illuminance
2Reliability
If a dynamic vision sensor operates in dark state to measure dark current, then reliability of light intensity detection is improved, but measurement precision deteriorates due to absence of light signal
Solution Approach 1:
The patent performs preliminary measurements using multiple photoreceptors even in the dark state before actual light detection. By capturing baseline measurements from multiple photoreceptors in advance, the system establishes reference data that can be used to compensate for dark current variations, improving the reliability of subsequent light intensity measurements
Solution Approach 2:
The system uses feedback from dark state measurements to continuously update and refine the dark current compensation model. The processing circuitry analyzes the differential measurements from multiple photoreceptors in the dark state and adjusts the compensation parameters, ensuring accurate dark current subtraction during actual operation
3Measurement precision
If multiple photoreceptors are used to measure photocurrent, then measurement precision is improved through differential calculation, but device complexity increases
Solution Approach 1:
The patent merges the measurement function across multiple photoreceptors into a unified differential calculation process. By combining the outputs of multiple photoreceptors and processing them through a shared calculation mechanism, the system achieves improved measurement precision while avoiding the complexity of completely independent measurement systems for each photoreceptor
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 accurate measurement of photocurrent and dark current even in low illuminance conditions, improving the reliability and optimizing the design of dynamic vision sensors for better low-light performance.
Implementation Method 1
each including at least one first pixel and at least one second pixel, respectively, the at least one first pixel and the at least one second pixel configured to generate at least one first photocurrent and at least one second photocurrent in response to an incident light
Data Source
AI summary
A dynamic vision sensor may include a pixel array including at least a first photoreceptor and a second photoreceptor, the first photoreceptor and the second photoreceptor including at least one first pixel and at least one second pixel, respectively, the at least one first pixel and the at least one second pixel configured to generate at least one first photocurrent and at least one second photocurrent in response to an incident light, respectively, and the first photoreceptor and the second photoreceptor configured to a first and second log voltages based on the at least one first photocurrent and the at least one second photocurrent, respectively, processing circuitry configured to, amplify the first and second log voltages, detect a change in intensity of the light based on the amplified first log voltage, the amplified second log voltage, and a reference voltage, and output an event signal corresponding to the detected value.