Event Camera Tile Buffer for Sparse Image Frame Reconstruction

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Solution Overview

Problem

Existing methods for processing event camera data require excessive memory allocation for all pixels, including non-moving parts of the scene, leading to inefficient memory usage.

Innovation Solution

Implementing a tile buffer system that only stores information for a subset of pixels, using a preliminary decoder to count and extract timestamp information from event packets, and performing additional filtering to remove regions with low event numbers, thereby minimizing memory usage and avoiding storage of noise in the tile buffer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If memory is allocated for all pixels in the event camera sensor, then complete image reconstruction is possible, but memory usage becomes excessive and inefficient

Engineering Contradiction:
Improvememory allocationVSAvoidprocessing efficiency
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The patent extracts only the necessary portion of data from the complete event camera output by identifying and processing only those pixels that have generated events. The system separates moving objects (generating events) from static background (not generating events), allocating memory only for the relevant subset of pixels rather than all pixels in the sensor array.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies different memory allocation strategies to different regions of the image based on their characteristics. Regions with detected events receive memory allocation for processing, while regions without events (static background) do not receive allocation. This local differentiation optimizes memory usage by matching resource distribution to actual processing needs.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If a tile buffer is sized to store information for all pixels, then no information is lost, but the buffer size becomes unnecessarily large

Engineering Contradiction:
Improvebuffer sizeVSAvoidevent data completeness
Core Design Contradiction:
Quantity of substanceVSLoss of information

Solution Approach 1:

The patent segments the image buffer into multiple tiles, where each tile corresponds to a subset of pixels. By dividing the complete image into smaller manageable tiles, the system can allocate buffer space only for tiles containing events rather than pre-allocating space for the entire image, reducing overall buffer size while maintaining completeness of event data.

Inventive Principle:
Principle #1Segmentation

3Productivity

If the tile buffer stores information for static background regions, then complete scene coverage is achieved, but noise storage increases and buffer efficiency decreases

Engineering Contradiction:
Improvebuffer efficiencyVSAvoidnoise filtering
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent performs preliminary filtering to identify and remove static background regions from the tile buffer before processing. By detecting which pixels have generated events and excluding static regions in advance, the system prevents noise from being stored in the buffer, improving buffer efficiency and signal-to-noise ratio for the actual processing work.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4169242B1Producing an image frame using data from an event camera
Publication Date: 2024.05.01 TOBII TECHNOLOGIES LTD
  • EP4169242B1 patent drawingFigure 1
  • EP4169242B1 patent drawingFigure 2
  • EP4169242B1 patent drawingFigure 3

AI summary

A method of producing an image frame from event packets received from an event camera comprises: forming a tile buffer sized to accumulate event information for a subset of image tiles, the tile buffer having an associated tile table that determines a mapping between each tile of the image frame for which event information is accumulated in the tile buffer and the image frame. For each event packet: an image tile corresponding to the pixel location of the event packet is identified; responsive to the tile buffer storing information for one other event corresponding to the image tile, event information is added to the tile buffer; and responsive to the tile buffer not storing information for another event corresponding to the image tile and responsive to the tile buffer being capable of accumulating event information for at least one more tile, the image tile is added to the tile buffer.