Logarithmic Pixel Array Reduces Circuit Scale in Solid-State Image Sensors
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Solution Overview
Problem
Asynchronous solid-state image sensors, like dynamic vision sensors, achieve high-speed data generation but face challenges with increased circuit scale due to the large number of transistors in detection circuits for each pixel, making them unsuitable for applications requiring lower circuit complexity.
Innovation Solution
A solid-state image sensor design incorporating a pixel array with logarithmic response pixels that output analog signals proportional to incident light and detection pixels that detect threshold exceedance, along with a drive circuit to manage these signals, reducing circuit complexity by separating functions between pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an asynchronous solid-state image sensor with detection circuit for each pixel is used to detect address events in real time, then processing speed is improved, but circuit scale increases due to larger number of transistors per pixel
Solution Approach 1:
The invention divides the pixel array into two distinct types: detection pixels that detect address events and output detection signals, and logarithmic response pixels that output analog signals proportional to logarithmic values of incident light amounts. This segmentation allows each pixel type to have a simplified circuit structure suitable for its specific function, rather than every pixel requiring the full detection circuitry, thereby reducing overall circuit scale while maintaining high-speed address event detection capability
Solution Approach 2:
The invention creates a multi-functional pixel array where detection pixels and logarithmic response pixels work together to provide both address event detection and image data capture capabilities. The detection pixels specialize in detecting light amount changes exceeding thresholds, while logarithmic response pixels provide continuous analog output for image formation. This functional differentiation allows the system to achieve high-speed processing for address events without requiring every pixel to have complex detection circuits
2Measurement precision
If a detection circuit with many transistors is provided for each pixel to detect address events, then detection capability is improved, but manufacturing cost increases due to higher circuit complexity
Solution Approach 1:
The invention applies local quality by giving different structural characteristics to different regions of the pixel array. Detection pixels are designed with specific circuit configurations optimized for detecting light amount changes, while logarithmic response pixels use different circuit configurations optimized for generating analog signals proportional to logarithmic light values. This localized optimization allows each region to have the precise quality needed for its function without imposing unnecessary complexity on all pixels, thereby improving detection capability while controlling manufacturing costs
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 design enables efficient detection of address events while capturing image data, reducing circuit scale and improving processing speed without the need for extensive transistor arrays at each pixel.
Implementation Method 1
a photoelectric conversion element configured to generate a photocurrent by photoelectric conversion
Data Source
AI summary
To reduce a circuit scale in a solid-state image sensor that detects an address event. The solid-state image sensor includes a pixel array unit and a drive circuit. In the solid-state image sensor, in the pixel array unit, a logarithmic response pixel that outputs an analog signal proportional to a logarithmic value of an incident light amount and a detection pixel that detects whether or not a change amount of the incident light amount has exceeded a predetermined threshold and outputs a detection signal indicating a detection result are arrayed. Furthermore, in the solid-state image sensor, the drive circuit drives the logarithmic response pixel and the detection pixel to output the analog signal and the detection signal.