Event-Based Image Sensor Row Selection Arbiter
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Solution Overview
Problem
Event-based image sensors experience high power consumption due to frequent memory accesses and processing of numerous events, especially when higher resolutions are required, which is not addressed by existing technologies.
Innovation Solution
A method for operating an event-based image sensor that involves a pixel array with a readout circuit that samples and resets pixel circuits on a row-by-row basis, using an arbiter tree to select rows based on a predetermined rule, reducing unnecessary memory accesses and optimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frequent memory accesses are performed to process numerous events from high-resolution pixels, then event processing capability is improved, but power consumption increases substantially
Solution Approach 1:
The patent implements preliminary action by pre-selecting and prioritizing row requests before memory access occurs. The arbiter circuit预先 evaluates and queues row access requests based on priority criteria, so that when memory access is needed, the system already has an optimized sequence ready, reducing the need for frequent random access operations and thereby lowering power consumption while maintaining event processing capability
Solution Approach 2:
The patent applies segmentation by dividing the pixel array into multiple rows with independent request lines, allowing parallel processing of row access requests. This segmentation enables the system to handle multiple events simultaneously across different rows, improving overall event processing throughput while the prioritization mechanism ensures that only necessary rows are accessed, reducing total memory access operations and power consumption
2Reliability
If SRAM memory is accessed frequently to store and retrieve pixel data for processing, then data availability for processing is improved, but operational power consumption increases
Solution Approach 1:
The arbiter circuit performs preliminary evaluation and prioritization of row access requests before memory access occurs. By pre-determining which rows need to be accessed and in what order, the system minimizes the number of actual memory access operations required, thereby maintaining data availability for processing while significantly reducing the operational power consumption of the SRAM memory
Solution Approach 2:
The arbiter circuit acts as an intermediary between the pixel circuits and the SRAM memory. It receives access requests from multiple rows, prioritizes them according to predefined criteria, and sequences the memory access operations accordingly. This intermediary function ensures that data is available when needed while optimizing the access pattern to minimize power consumption
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 method significantly reduces power consumption while maintaining resolution and sensitivity by minimizing unnecessary memory accesses and leveraging sparse illumination events, allowing for efficient event processing.
Implementation Method 1
a photoreceptor signal derived from a photocurrent generated by a light impinging on a light-sensitive element
Data Source
Figure 1~2
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AI summary
A method for operating an event-based image sensor comprising a plurality of pixel circuits (1), each configured to detect an illumination change to consequently activate a row request, wherein the pixel array comprises a readout circuit (14), wherein: - at the beginning of the readout cycle, the row requests which are activated at said beginning are sampled into activated sampled row requests, - the activated sampled row requests are selected sequentially by an organizer, and in each row with a selected sampled activated row request, each pixel circuit with an activated row request is read and reset before another row is selected, until all the sampled activated row requests have been selected, wherein the rows are associated with a row order, and the organizer selects the sampled activated row requests in a sequence organized by predetermined rules based on respective row orders of the rows with the sampled activated row requests.