Optical Processing System for Convolutional Neural Network Acceleration

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Solution Overview

Problem

Convolutional neural networks (CNNs) face significant computational burdens during training and inference, particularly due to the high load of convolutional layers, which can be time-consuming even with state-of-the-art GPU implementations, and increasing resolution further exacerbates this issue.

Innovation Solution

An optical processing system using a 4f optical correlator with spatial light modulators (SLMs) is employed to perform optical convolutions, where input data patterns and Fourier domain representations of kernel patterns are displayed to achieve parallel convolutions, leveraging the system's ability to handle 2D convolutions more efficiently than digital methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If digital convolution algorithms are used on GPU or FPGA architectures, then computational accuracy is maintained, but processing speed is insufficient

Engineering Contradiction:
Improveprocessing speedVSAvoidcomputational throughput
Core Design Contradiction:
SpeedVSProductivity

Solution Approach 1:

The patent replaces digital computational systems (GPU/FPGA) with an optical processing system that uses light to perform convolution operations. The optical correlator uses spatial light modulators and lenses to physically compute convolutions at the speed of light, eliminating the sequential processing limitations of digital systems and achieving parallel computation across the entire image domain.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transitions from temporal processing (sequential digital computation) to spatial processing (parallel optical computation). By mapping the convolution operation into the spatial domain using optical fields, the system processes all pixel values simultaneously across the image plane, effectively adding a spatial dimension to the computation that enables massive parallelism.

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

2Measurement precision

If convolutional layers use high resolution input or kernel sizes, then network accuracy is improved, but computational burden increases significantly

Engineering Contradiction:
Improvenetwork accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The optical system handles high-resolution convolutions by using the physical properties of light and optics rather than digital computation. The spatial light modulators can display high-resolution patterns, and the optical correlation process naturally handles the computational complexity of large kernels through parallel physical operations, avoiding the exponential increase in digital computational requirements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If the number of convolutional layers is increased, then network performance is improved, but training time becomes excessively long

Engineering Contradiction:
Improvenetwork performanceVSAvoidtraining time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces slow digital training computations with fast optical processing for the convolution operations that dominate training time. By using optical correlators to perform the majority of computational work in parallel at light speed, the system can train deeper networks without the weeks-long training durations required by sequential digital processors.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 accelerates the training and inference processes of CNNs by exploiting the optical system's capabilities, allowing for improved performance and reduced computational time, particularly through tiling techniques that maximize hardware resolution and parallel processing.

Implementation Method 1

The SLMs have a dynamic modulating effect on impinging light

Methodology Applied
Scientific EffectOptical modulation: Phase Modulation

Implementation Method 2

the data focusing pattern which is in the Fourier plane, the data focusing pattern being a Fourier domain representation of a second input data pattern

Methodology Applied
Scientific EffectFourier transformation:

Implementation Method 3

a detector for detecting light that has been successively optically processed

Methodology Applied
Scientific EffectPhotoelectric detection: Photoelectric Effect

Data Source

PatentUS12033066B2Optical processing systems
Publication Date: 2024.07.09 OPTALYSYS
  • US12033066B2 patent drawing
  • US12033066B2 patent drawing
  • US12033066B2 patent drawing

AI summary

An optical processing system comprises at least one spatial light modulator, SLM, configured to simultaneously display a first input data pattern (a) and at least one data focusing pattern which is a Fourier domain representation (B) of a second input data pattern (b), the optical processing system further comprising a detector for detecting light that has been successively optically processed by said input data patterns and focusing data patterns, thereby producing an optical convolution of the first and second input data patterns, the optical convolution for use in a neural network.