Asynchronous Image Sensor Transient Detection for Data Reduction
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Solution Overview
Problem
Conventional image sensors face limitations in handling high-resolution data due to limited data transmission rates and high energy consumption, particularly in mobile applications, and struggle to efficiently process information about stationary objects or backgrounds, leading to redundant data generation and limited dynamic range.
Innovation Solution
An image sensor system that asynchronously detects brightness changes in pixels, transmitting data only when changes occur, using a photodetector circuit with an integrating capacitor and threshold comparator to measure exposure, allowing for continuous image recording with high time and intensity resolution, and reducing data volume by suppressing temporal redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If conventional image sensors read out all pixels at a predetermined frame rate, then complete image information is captured, but data transmission rate limits are exceeded and energy consumption becomes too high
Solution Approach 1:
The patent extracts only the essential and changed information from the scene by using transient detectors that respond only to brightness changes. Instead of transmitting all pixel data at every frame rate, the system extracts and transmits only transient events (changes in brightness), thereby reducing data volume while preserving important image information.
Solution Approach 2:
The patent implements dynamic adaptation of the imaging system by allowing pixels to operate autonomously and asynchronously. Each pixel independently detects brightness changes and triggers readout only when necessary, rather than following a fixed synchronous readout schedule. This dynamic behavior reduces data transmission while maintaining information completeness.
2Loss of information
If conventional image sensors read out all pixels at a predetermined frame rate, then complete image information is captured, but energy consumption becomes too high for mobile applications
Solution Approach 1:
The patent extracts only the essential and changed information from the scene by using transient detectors that respond only to brightness changes. Instead of continuously reading out all pixel data, the system extracts only transient events, thereby reducing energy consumption while preserving important image information.
Solution Approach 2:
The patent implements periodic action through event-driven readout triggered by brightness changes. Rather than continuous synchronous readout at fixed frame rates, the system performs readout operations periodically only when transients are detected, significantly reducing energy consumption while maintaining information completeness.
3Productivity
If optical transient sensors detect only brightness changes asynchronously, then data volume is reduced and time resolution is improved, but information about stationary objects and background is lost
Solution Approach 1:
The patent merges the advantages of transient sensing with conventional imaging by combining transient detectors with frame memory. The system captures both transient events (for reduced data volume and high time resolution) and complete frame information (for stationary objects and background), integrating multiple sensing approaches into a unified system.
Solution Approach 2:
The patent implements multi-functionality by designing an image sensor that can operate in multiple modes: transient detection mode for dynamic scenes with reduced data volume, and complete frame capture mode for stationary objects. The same sensor hardware serves multiple purposes, adapting its function based on scene requirements.
4Ease of operation
If conventional image sensors use clocked readout at fixed frame rate, then synchronous data transmission is achieved, but temporal resolution is limited and dynamic range is restricted
Solution Approach 1:
The patent implements dynamic adaptation of the imaging system by allowing pixels to operate autonomously and asynchronously. Each pixel independently detects brightness changes and triggers readout only when necessary, rather than following a fixed synchronous readout schedule. This dynamic behavior reduces data transmission while maintaining information completeness.
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 efficient data transmission with high time resolution and wide dynamic range, reducing power consumption and data volume while maintaining high image quality, suitable for applications requiring variable scene information without redundant data from stationary areas.
Implementation Method 1
an exposure measurement on an autonomous image element is triggered by a first photodetector by an event of an independent, asynchronous detection of a brightness change in the scene section viewed from the picture element by a further photodetector
Implementation Method 2
The electronic circuit, transient detector, on which these picture elements are based
Data Source
AI summary
A method for continuously generating a (greyscale) map of a scene in electronic form, characterized by high time resolution and minimal data volume, is presented. The method involves repeated measurement of the instantaneous exposure of the image elements in an image sensor, the start of every exposure measurement being determined autonomously and asynchronously by every image element independently, and hence the redundancy which is typical of synchronous image sensors in the image data to be transmitted being largely suppressed. The stimulation for the purpose of exposure measurement is provided by the autonomous detection of a relative brightness change in the scene detail which the image element views, by the transient detector in the respective image element. To increase the signal-to-noise ratio and the dynamic range, the exposure measurement is preferably performed on the basis of time, that is to say the exposure of an image element is represented by the period between two asynchronous events. The address of the image element, corresponding to the coordinates of the image element in the sensor array, is transmitted asynchronously at the time of every detection of a brightness change for the purpose of storage and/or further processing. In addition, the result of the resultant exposure measurement is likewise transmitted together with the address of the image element, asynchronously for the purpose of storage and/or further processing. No external control signals are required for controlling timing, particularly for the exposure measurement. The image sensor is typically implemented in CMOS technology.