ISP Subblock Intra Prediction Mode Encoding

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Solution Overview

Problem

The increasing demand for high-resolution and high-quality images, such as HD and UHD images, leads to a significant increase in the amount of transmitted and stored information, resulting in higher costs for transmission and storage.

Innovation Solution

An image encoding/decoding method and apparatus that employs an ISP mode, where a current block is partitioned into subblocks for intra prediction, with each subblock having a prediction mode determined based on neighboring reference samples, and only the intra prediction mode of one subblock is encoded in the bitstream.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

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

Engineering Contradiction:
Improveimage qualityVSAvoidamount of transmitted information
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The current block is partitioned into multiple subblocks (first subblock, second subblock, etc.) for independent intra prediction processing. This segmentation allows each subblock to be processed with optimized prediction modes, improving compression efficiency while maintaining image quality, thereby reducing the total data volume needed for transmission and storage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different intra prediction modes are determined for different subblocks based on their specific characteristics and neighboring reference samples. This local optimization ensures that each subblock is encoded with the most efficient prediction mode, maximizing compression ratios while preserving local image details and quality.

Inventive Principle:
Principle #3Local quality

2Productivity

If intra prediction mode is determined for each subblock, then encoding efficiency is improved, but bitstream data volume increases

Engineering Contradiction:
Improveencoding efficiencyVSAvoidbitstream data volume
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

Only the intra prediction mode information of the first subblock is explicitly encoded in the bitstream, while the intra prediction mode of the second subblock is derived through prediction mode extension using neighboring reference samples. This extraction of only necessary information reduces bitstream data volume while maintaining encoding efficiency through intelligent prediction mode determination.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The second subblock's intra prediction mode is automatically determined through prediction mode extension based on neighboring reference samples, without requiring explicit encoding. This self-determination mechanism reduces the bitstream data volume by eliminating redundant information while maintaining encoding efficiency through intelligent prediction mode derivation.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4550779A1ISP mode-based image encoding/decoding method and device, and recording medium for storing bitstream
Publication Date: 2025.05.07 LG ELECTRONICS INC
  • EP4550779A1 patent drawingFigure 1
  • EP4550779A1 patent drawingFigure 2
  • EP4550779A1 patent drawingFigure 3

AI summary

An image encoding/decoding method and apparatus are provided. The image decoding method may comprise partitioning a current block into a plurality of subblocks based on intra sub-partitions (ISP) prediction being applied to the current block, determining an intra prediction mode of each of the plurality of subblocks, and generating a prediction block of each of the plurality of subblocks based on the determined intra prediction mode. The plurality of subblocks may include a first subblock and a second subblock, an intra prediction mode of the first subblock may be determined based on prediction mode information of the first subblock or a first neighboring reference sample of the first subblock, and an intra prediction mode of the second subblock may be determined based on a second neighboring reference sample of the second subblock.