Event-Based Sensor Dark Current Noise Subtraction
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Solution Overview
Problem
Existing image sensors face challenges in low-illuminance and high-temperature environments due to noise interference from dark currents, which affect their reliability and performance.
Innovation Solution
An event-based sensor design that incorporates a dummy pixel and a current mirror to generate a mirrored current, allowing the subtraction of dark current noise from the sense current, thereby improving the sensor's ability to accurately detect light variations without synchronization, reducing power consumption, and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional image sensor is used to detect light variations, then the sensor can operate in various lighting conditions, but dark current noise interferes with detection accuracy in low-illuminance and high-temperature environments
Solution Approach 1:
The pixel array is divided into sensing pixels for light detection and dummy pixels for dark current measurement. This segmentation allows independent measurement and subtraction of dark current noise from the sense current, thereby improving detection accuracy in low-illuminance and high-temperature environments without compromising the main sensing function
Solution Approach 2:
Dummy pixels act as intermediary elements that measure dark current noise separately. The measured dark current from dummy pixels is then subtracted from the sense current in sensing pixels, serving as a mediator to eliminate noise interference and improve measurement precision
2Reliability
If the sensor continuously measures and processes light signals to maintain high detection reliability, then detection accuracy improves, but power consumption increases
Solution Approach 1:
The sensor employs event-driven periodic action where processing is triggered only when light variations exceed a threshold. The controller periodically reads out activation signals from sensing pixels and subtracts dark current measurements from dummy pixels only when needed, maintaining high detection reliability while minimizing unnecessary processing and reducing power consumption during stable lighting conditions
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 solution effectively removes dark current noise, improving the sensor's performance in low-illuminance and high-temperature conditions, enabling faster and more reliable human-computer interaction with reduced power consumption.
Implementation Method 1
a sensing pixel configured to generate a sense current based on an intensity of incident light
Implementation Method 2
a dummy pixel configured to generate a dark current
Data Source
AI summary
An event-based sensor includes a dummy pixel that generates a dark current, a current mirror that generates a mirrored current using the dark current, and a sensing pixel that generates a sense current based on an intensity of incident light, and outputs an activation signal, indicating whether a variation in the incident light is sensed, based on a light current that is obtained by subtracting the mirrored current from the sense current.