Chroma QP Mapping in Image Decoding for Adaptive Compression

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Solution Overview

Problem

The increasing demand for high-resolution and high-quality images leads to increased transmission and storage costs due to the higher amount of information required, necessitating a more efficient image compression technique.

Innovation Solution

Deriving a chroma quantization parameter using a chroma QP mapping table based on signaled data, rather than a default table, to improve coding efficiency by reflecting the image's characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a default chroma QP mapping table is used, then the decoding process is simple, but the coding efficiency is low and does not reflect image characteristics

Engineering Contradiction:
Improvecoding efficiencyVSAvoiddecoding process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The chroma QP mapping table is pre-derived and stored in the decoding apparatus before actual decoding operations. This preliminary preparation allows the system to use image characteristic information that has been pre-processed and organized into a usable table format, improving coding efficiency without adding complexity during the actual decoding process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses a chroma QP mapping table that is copied or derived from luma QP mapping table information. By copying the structural framework from the well-established luma table and adapting it for chroma components using derived characteristics, the system achieves improved efficiency while maintaining procedural simplicity.

Inventive Principle:
Principle #26Copying

2Manufacturing precision

If high-resolution and high-quality images are transmitted, then image quality is improved, but transmission cost and storage cost increase

Engineering Contradiction:
Improveimage qualityVSAvoiddata volume
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the chroma quantization parameter based on image characteristics. By changing the QP value according to the specific properties of each image (such as complexity, content type, and visual characteristics), the system optimizes the balance between image quality and data volume, reducing unnecessary transmission and storage costs while maintaining acceptable quality.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system applies different quality levels to different parts of the image data. By analyzing local image characteristics and applying adaptive quantization parameters specifically for chroma components in different regions, the system maintains high quality where needed while reducing data volume in less critical areas, thereby reducing overall transmission and storage requirements.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS20250379980A1Image decoding method and device therefor
Publication Date: 2025.12.11 LG ELECTRONICS INC
  • US20250379980A1 patent drawing
  • US20250379980A1 patent drawing
  • US20250379980A1 patent drawing

AI summary

An image decoding method performed by a decoding device, according to the present document, comprises the steps of: obtaining image information through a bitstream; and generating a reconstructed picture on the basis of the image information.