Photoarray Asynchronous Change Detection Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Real-time artificial vision systems using photoarrays are limited by high frame rates that generate excessive redundant data, making them inefficient for detecting fast changes and unsuitable for static scenes.
Innovation Solution
A photoarray that uses a single photodiode or phototransistor to both detect asynchronous change events and estimate brightness, reducing data processing by only transmitting data when light intensity changes, and employing a brightness readout circuit to determine photocurrent magnitude at a low sample rate, allowing for low latency and reduced data redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a high frame rate is used to detect fast changing things, then the detection speed is improved, but the amount of redundant data generated increases significantly
Solution Approach 1:
The patent extracts only the essential information (brightness changes exceeding a threshold) from the continuous light signal, rather than transmitting all frame data. The change detection circuit identifies and transmits only when brightness changes surpass a predefined threshold, filtering out redundant data while preserving critical temporal contrast information.
Solution Approach 2:
The patent transforms the continuous brightness parameter into discrete event signals by applying a threshold condition. When the brightness change exceeds the threshold, an event is generated; otherwise, no data is transmitted. This parameter transformation converts a continuous data stream into sparse discrete events, dramatically reducing data volume while maintaining detection capability for fast changes.
2Productivity
If a low frame rate is used to reduce data processing, then data processing requirements are reduced, but the ability to detect fast changes is degraded
Solution Approach 1:
The patent implements a dynamic data transmission system where the sampling rate adapts to scene activity. During static scenes, no data is transmitted (effectively infinite frame rate). During fast changes, events are transmitted asynchronously with high temporal resolution. This dynamic approach allows the system to maintain high detection capability for fast changes while achieving low data processing requirements through adaptive sampling.
Solution Approach 2:
The change detection circuit autonomously monitors brightness changes and self-regulates data transmission based on scene content. The system automatically detects when changes exceed the threshold and triggers event transmission without external control, enabling the photoarray to adapt its data output to actual scene dynamics and eliminate redundant transmissions during static periods.
3Quantity of substance
If asynchronous change detection is used to reduce data redundancy, then data redundancy is reduced, but the ability to sense static scenes is lost
Solution Approach 1:
The patent makes the single photodiode universal by implementing two distinct readout modes: asynchronous change detection for dynamic scenes and periodic brightness sampling for static scenes. The change detection circuit can operate independently for motion detection, while the brightness readout circuit provides periodic absolute brightness measurements for static scene monitoring. This multi-functionality allows the same hardware to adapt to different scene types without sacrificing either capability.
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 significantly reduces data processing requirements and latency, enabling efficient real-time artificial vision by transmitting only necessary data and maintaining high time resolution.
Implementation Method 1
each cell having a means (e.g. a photodiode or a phototransistor) for generating a signal (e.g. photocurrent) depending on a light intensity at the respective cell
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a photoarray(1), comprising: a plurality of cells (10), wherein each of said cells (10) comprises a means (20)that is configured to generate a photocurrent (I) being proportional to the intensity (L) of the light impinging on the respective cell(10), and wherein each of said cells (10) comprises a change detection circuit(100) connected to the respective means (20) for generating the photocurrent (I), which change detection circuit (100) is configured to generate an output signal merely in case a change event occurs at which said intensity (L) changes by a threshold amount (T, T') since the preceding change event from the respective cell (10). According to the invention said means (20) for generating said photocurrent (I) is additionally also used to estimate the magnitude of the said photocurrent (I) being a measure of the brightness of the light at the respective cell (10).