Online Meta-Learned Image Compression via CVAE Adaptation

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Solution Overview

Problem

Current image compression techniques, such as those in JPEG and video coding standards, face challenges in achieving smaller image sizes without significantly sacrificing image quality, especially for large-scale image capture and storage applications, and lack efficient computational methods for variable compression rates.

Innovation Solution

The implementation of an Online Meta Learning (OML) framework based on a Conditional Variational Auto-Encoder (CVAE) architecture for learned image compression (LIC), which adapts meta-control variables to balance reconstruction quality and bitrate, enabling efficient online learning and meta-learning for variable compression rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lossy compression techniques are used to reduce image size, then compression ratio is improved, but image quality deteriorates

Engineering Contradiction:
Improveimage sizeVSAvoidimage quality
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by transforming image data from spatial domain to frequency domain using DCT, then selectively quantizing different frequency components. This allows the system to adjust compression parameters dynamically - preserving low-frequency components that carry essential image information while aggressively compressing high-frequency components, thereby achieving better compression ratios with minimal quality loss.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements local quality through differential quantization where different blocks of image data receive different quantization strengths based on their importance. The quantization parameter varies across different frequency bands and spatial regions, allowing critical image areas to maintain higher quality while less important areas are more aggressively compressed.

Inventive Principle:
Principle #3Local quality

2Productivity

If machine learning techniques are incorporated into image coding standards, then compression efficiency is improved, but computational complexity increases

Engineering Contradiction:
Improvecompression efficiencyVSAvoidcomputational complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical/image-processing-based compression methods with machine learning models. Specifically, it uses trained neural networks to perform complex tasks such as predicting residual blocks, modeling context probabilities, and optimizing quantization parameters, substituting iterative algorithmic approaches with direct neural network inference that achieves better compression efficiency.

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

Solution Approach 2:

The patent applies preliminary action through extensive offline training of machine learning models on large image datasets. The models learn optimal compression strategies during training, and during actual compression operations, these pre-trained models directly apply learned patterns without requiring complex runtime optimization, reducing computational complexity during deployment.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If variable compression rates are implemented, then adaptability is improved, but system complexity increases

Engineering Contradiction:
Improvevariable compression ratesVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamics by making the compression system adaptive to different compression rate requirements. The machine learning models can dynamically adjust their operation based on target compression rates, selecting different quantization parameters, context modeling strategies, and even different network configurations to optimize performance for specific compression targets.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent achieves universality through a unified machine learning-based compression framework that can handle multiple compression rates using the same core architecture. The system uses a single trained model that can operate at different compression levels by adjusting parameters, eliminating the need for separate specialized systems for each compression rate.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS20240020887A1Conditional variational auto-encoder-based online META-learned image compression
Publication Date: 2024.01.18 ALIBABA DAMO (HANGZHOU) TECH CO LTD
  • US20240020887A1 patent drawing
  • US20240020887A1 patent drawing
  • US20240020887A1 patent drawing

AI summary

An Online Meta Learning (“OML”) framework is provided for learned image compression (“LIC”) based on a variable-rate Conditional Variational Auto-Encoder (“CVAE”) architecture. A computing system is configured to learn, from multiple training tasks of compression with different RD tradeoff λs, a set of task-general meta parameters controlled by meta-control variables Λ. Meta parameters learn a mapping between the meta-control variables Λ and compression effects of different RD tradeoffs λs. Meta-control variables Λ are adaptively determined and transmitted on the fly to an encoder and a decoder of an image compression process, to accommodate the current compression need for any current test datum. A parallelized context computation method is also provided for an online CVAE-based meta-LIC architecture; since OML requires multiple iterations at an encoder, parallel context estimation substantially improves computational time in practice.