360-Degree Video Adaptive Quantization for Projection Artifacts

Solution Overview

Problem

The high information density of 360-degree videos increases transmission and storage costs due to the need for efficient compression techniques to effectively transmit and reproduce these videos in virtual reality systems.

Innovation Solution

An adaptive quantization parameter method is introduced for 360-degree video encoding and decoding, which derives a decoder-side adaptive quantization parameter (DAQP) based on the projection type and weight map of the projected picture, improving coding efficiency by reflecting geometric structures and reducing artifacts at discontinuities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional uniform quantization parameters are used for 360-degree video encoding, then the encoding process is simple, but coding efficiency is poor and transmission costs increase

Engineering Contradiction:

Improvecoding efficiencyVSAvoidquantization parameter processing complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies local quality by deriving different quantization parameters for different regions of the projected picture based on projection type and weight maps. Specifically, regions with higher weights (更重要区域) receive different quantization parameters compared to regions with lower weights, allowing important areas to maintain higher quality while less important areas use more aggressive compression, thereby improving overall coding efficiency.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the quantization parameter values based on the projection type (e.g., equirectangular, cube map) and the weight map of different regions. By dynamically adjusting QP values according to regional importance and projection characteristics, the system optimizes compression efficiency while maintaining visual quality in critical areas.

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If high compression is applied to reduce transmission costs, then transmission overhead decreases, but image quality and subjective perception deteriorate

Engineering Contradiction:

Improvetransmission overheadVSAvoidimage quality

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The patent applies local quality by deriving different quantization parameters for different regions of the projected picture based on projection type and weight maps. Specifically, regions with higher weights (更重要区域) receive different quantization parameters compared to regions with lower weights, allowing important areas to maintain higher quality while less important areas use more aggressive compression, thereby improving overall coding efficiency.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the quantization parameter values based on the projection type (e.g., equirectangular, cube map) and the weight map of different regions. By dynamically adjusting QP values according to regional importance and projection characteristics, the system optimizes compression efficiency while maintaining visual quality in critical areas.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If uniform quantization is used across all regions, then processing is simpler, but artifacts occur at discontinuity boundaries of projected pictures

Engineering Contradiction:

Improvequantization processing complexityVSAvoidartifacts at discontinuity boundaries

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by deriving different quantization parameters for different regions of the projected picture based on projection type and weight maps. Specifically, regions with higher weights (更重要区域) receive different quantization parameters compared to regions with lower weights, allowing important areas to maintain higher quality while less important areas use more aggressive compression, thereby improving overall coding efficiency.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the quantization parameter values based on the projection type (e.g., equirectangular, cube map) and the weight map of different regions. By dynamically adjusting QP values according to regional importance and projection characteristics, the system optimizes compression efficiency while maintaining visual quality in critical areas.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11051020B2Image decoding method and apparatus using projection-type based quantisation parameters in image coding system for 360-degree video

Publication Date: 2021.06.29 LG ELECTRONICS INC

AI summary

An image decoding method that is performed by a decoding apparatus of the present invention comprises the steps of: receiving 360-degree video information; deriving a projection type of a projected picture based on the 360-degree video information; deriving a weight map of the projected picture based on the projection type; deriving quantisation processing units of the projected picture; deriving DAQP for the respective quantisation processing units based on the weight map; and decoding the respective quantisation processing units based on the DAQP.