Event Camera Motion Estimation Using Neural Network Time Discretization

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Solution Overview

Problem

Existing methods for estimating motion from event-based camera images lose temporal resolution and face high computational complexity, as they discard or round event timestamps, making it challenging to effectively predict optical flow, depth, and egomotion in machine vision applications.

Innovation Solution

A method involving the use of an encoder-decoder neural network that receives time-discretized event volumes from event-based cameras, where each event represents a change in pixel intensity, polarity, and timestamp, and generates predictions of motion by applying a loss function that measures image deblurring quality, allowing for the preservation of temporal information and reduced computational complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If event timestamps are discarded or rounded to reduce computational complexity, then processing speed improves, but temporal resolution is lost

Engineering Contradiction:
Improveprocessing speedVSAvoidtemporal resolution
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent transforms the 1D timestamp values into 2D spatial coordinates by mapping temporal information to the spatial domain through event accumulation images. Each event's timestamp is converted to a spatial position in an accumulation image, where the x-y coordinates represent spatial location and the intensity represents temporal frequency. This dimensional transformation allows the neural network to process temporal information spatially, maintaining precision while reducing computational complexity through standard CNN operations.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If event timestamp information is preserved to maintain temporal resolution, then measurement precision improves, but computational complexity increases

Engineering Contradiction:
Improvetemporal resolutionVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the essential temporal information from event timestamps by accumulating events into intensity-based images. Instead of processing full timestamp sequences, the method extracts temporal frequency information through event accumulation, where each pixel's intensity represents the number of events at that spatial location over time. This extraction reduces computational complexity by converting complex temporal sequences into simple intensity values that can be processed efficiently by neural networks.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If traditional neural network methods are used to estimate motion from event-based cameras, then motion estimation capability is achieved, but temporal resolution is degraded due to timestamp discarding or rounding

Engineering Contradiction:
Improvemotion estimation capabilityVSAvoidtemporal resolution
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent changes the parameter representation from discrete timestamp values to continuous intensity values in event accumulation images. By transforming temporal parameters into spatial intensity parameters, the method enables neural networks to process event-based data while preserving temporal information. The intensity at each pixel location encodes the temporal frequency of events, allowing the network to learn motion patterns without discarding temporal precision.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11288818B2Methods, systems, and computer readable media for estimation of optical flow, depth, and egomotion using neural network trained using event-based learning
Publication Date: 2022.03.29 THE TRUSTEES OF THE UNIV OF PENNSYLVANIA
  • US11288818B2 patent drawing
  • US11288818B2 patent drawing
  • US11288818B2 patent drawing

AI summary

A method for prediction of an indication of motion using input from an event-based camera includes receiving events captured by an event-based camera, wherein each of the events represents a location of a change in pixel intensity, a polarity of the change, and a time. The method further includes discretizing the events into time discretized event volumes, each of which contain events that occur within a specified time range. The method further includes providing the time discretized event volumes as input to an encoder-decoder neural network trained to predict an indication of motion using a loss function that measures quality of image deblurring; generating, using the neural network, a prediction of the indication of motion. The method further includes using the prediction of the indication of motion in a machine vision application.