Stochastic Quantization for Auto-Encoder Parameter Convergence

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Solution Overview

Problem

In auto-encoders, the loss function cannot be differentiated with respect to quantized image feature amounts, leading to suboptimal parameter convergence and deteriorated image reconstruction quality due to the assumption of a differential value of 1 for quantized image feature amounts.

Innovation Solution

An information processing system that includes distribution estimation and sampling devices using machine learning models to determine and sample probability distributions within a predetermined value range, allowing for the generation of sample values and code sequences through entropy encoding and decoding, thereby optimizing model parameters under a combined loss function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If quantized image feature amounts are used in the loss function, then the parameter set can be updated using differential values, but the loss function cannot be differentiated with respect to quantized values leading to suboptimal parameter convergence

Engineering Contradiction:
Improveparameter convergence accuracyVSAvoidloss function differentiability
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces a stochastic quantization mechanism as an intermediary between continuous feature amounts and discrete code sequences. By treating quantization as a probabilistic process rather than a deterministic operation, the system enables gradient computation through the expectation of quantized values, allowing the loss function to be differentiated while still utilizing quantized representations for compression.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the parameter representation from fixed quantized values to probability distributions over quantized values. This parameter transformation allows the system to work with continuous probability distributions during training (enabling differentiation) while still producing discrete code sequences during inference (maintaining compression efficiency).

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the differential value of quantized image feature amounts is assumed to be 1, then the loss function can be computed, but the parameter set does not converge to an optimum solution causing deterioration in reconstructed image quality

Engineering Contradiction:
Improvereconstructed image qualityVSAvoidparameter convergence
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback mechanism where the quantization distribution parameters are learned and updated based on the loss function gradients. The system continuously adjusts the quantization strategy based on reconstruction error feedback, allowing the model to optimize both compression efficiency and reconstruction quality simultaneously through iterative training.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent transforms the static quantization process into a dynamic learned process. Instead of using fixed quantization thresholds, the system learns optimal quantization parameters through training, allowing the quantization behavior to adapt dynamically to the specific characteristics of the input data and optimization goals.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS20240078411A1Information processing system, encoding device, decoding device, model learning device, information processing method, encoding method, decoding method, model learning method, and program storage medium
Publication Date: 2024.03.07 NEC CORP
  • US20240078411A1 patent drawing
  • US20240078411A1 patent drawing
  • US20240078411A1 patent drawing

AI summary

A first distribution estimating device determines a first probability distribution of quantized values in a predetermined value range corresponding to an input value, by using a first machine learning model. A first sampling device samples the quantized values and determines a first sample value, using the first probability distribution. A second distribution estimating device determines a second probability distribution corresponding to the first sample value, by using a second machine learning model. A second sampling device samples the quantized values in the value range and determines a second sample value, using the second probability distribution. It can be implemented in the form of any of an information processing system, an encoding device, a decoding device, a model learning device, an information processing method, an encoding method, a decoding method, a model learning method, and a program storage medium.