Luma-Chroma Image Artifact Reduction via CNN and Luma-Aware Filtering

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Solution Overview

Problem

Compression of images by methods like JPEG and MPEG often results in distracting artifacts such as ringing and block artifacts, which degrade image quality and viewer experience.

Innovation Solution

The method involves separating an image into luma and chroma components, using a convolutional neural network to reduce artifacts in the luma component, and applying a luma-aware filter to the chroma component based on the cleaned luma component's coefficients, followed by combining the cleaned components to form a cleaned image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If image compression is applied to reduce storage and transmission requirements, then the number of bits required is reduced, but compression artifacts are introduced that degrade image quality

Engineering Contradiction:
Improvenumber of bitsVSAvoidcompression artifacts
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The image is separated into luma and chroma components, allowing different processing approaches for each component. The luma component undergoes artifact reduction using a convolutional neural network, while the chroma component uses a luma-aware filter, enabling targeted artifact removal without compromising overall image quality

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A convolutional neural network acts as an intermediary between the compressed image and the final output, learning to map compressed representations to high-quality images. The network serves as a mediator that translates compressed data into artifact-reduced images while preserving important visual information

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If compression quality is increased to reduce artifacts, then image quality is improved, but the number of bits required for storage and transmission increases

Engineering Contradiction:
Improvecompression artifactsVSAvoidnumber of bits
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The convolutional neural network learns to create a high-quality copy of the image from the compressed representation. Instead of storing or transmitting multiple versions at different qualities, the system learns to generate a high-quality reconstruction from the compressed data, effectively creating a virtual high-quality copy without the bit cost

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The system changes the representation parameters by transforming the image into different color spaces (luma-chroma separation) and applying different processing parameters to each component. This allows efficient artifact reduction in the luma component while maintaining compact representation

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If artifact reduction processing is applied to an image, then image quality is enhanced, but processing complexity increases

Engineering Contradiction:
Improvecompression artifactsVSAvoidprocessing complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

By segmenting the image into luma and chroma components, the system can apply simpler, more targeted processing to each component rather than applying complex general-purpose artifact reduction to the entire image. The luma component receives CNN-based processing while the chroma component uses lighter luma-aware filtering

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The image is pre-processed by separating luma and chroma components before artifact reduction, preparing the data in a format that enables more efficient processing. This preliminary segmentation simplifies subsequent artifact reduction operations by allowing component-specific optimization

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS10083499B1Methods and apparatus to reduce compression artifacts in images
Publication Date: 2018.09.25 GOOGLE LLC
  • US10083499B1 patent drawing
  • US10083499B1 patent drawing
  • US10083499B1 patent drawing

AI summary

Methods and apparatus to reduce compression artifacts in images are disclosed herein. An example method includes separating at least a portion of an image into a first component and a second component, reducing a first artifact in the first component to form a first cleaned component, reducing, using the first cleaned component, a second artifact in the second component to form a second cleaned component, and combining the first cleaned component and the second cleaned component to form a cleaned image.