Cubemap Projection Sampling Weighting for 360-Degree Video
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing 360-degree video coding technologies face inefficiencies due to non-uniform sampling in cube map projection formats, leading to quality disparities across the sphere and reduced coding efficiency, as well as challenges in providing immersive experiences in virtual reality environments.
Innovation Solution
The implementation of transform functions to convert non-uniform sampling grids into uniform grids, specifically using unicube map projection (UNICMP), equi-angular cubemap (EAC), and adjusted cubemap (ACP) projections, which adjust parameter weights based on spherical sampling densities to enhance coding efficiency and quality measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cube map projection format is used to code 360-degree video content, then the video can be represented in a structured format, but non-uniform sampling densities lead to quality disparities and reduced coding efficiency
Solution Approach 1:
The patent applies parameter changes by introducing transform functions that modify the sampling density distribution across the cube map projection. Specifically, it uses weighting parameters derived from the derivative values of transform functions to adjust the sampling density, converting non-uniform sampling into uniform sampling while maintaining coding efficiency through optimized parameter selection.
Solution Approach 2:
The patent implements preliminary action by pre-calculating weighting parameters and transform functions before the actual video coding process. The weighting parameters are determined in advance based on the derivative values of transform functions, allowing the coding system to operate with optimized uniform sampling without real-time computation overhead.
2Device complexity
If non-uniform sampling is used in cube map projection, then coding complexity is reduced, but quality measurement accuracy deteriorates
Solution Approach 1:
The patent changes the sampling parameter distribution from non-uniform to uniform by applying transform functions with carefully selected weighting parameters. This transformation maintains the simplicity of cube map projection while improving quality measurement accuracy through uniform sampling density across all regions of the 360-degree video content.
3Ease of manufacture
If traditional projection formats are used, then implementation is simpler, but spherical data representation is less accurate
Solution Approach 1:
The patent introduces transform functions as an intermediary between the simple cube map projection format and the requirement for accurate spherical data representation. These transform functions act as a mediator that converts standard cube map coordinates into uniformly sampled spherical coordinates, preserving implementation simplicity while achieving high representation accuracy.
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
360-degree video content may be coded. A sampling position in a projection format may be determined to code 360-degree video content. For example, a sampling position in a target projection format and a sampling position in a reference projection format may be identified. The sample position in the target projection format may be related to the corresponding sample position in the reference projection format via a transform function. A parameter weight (e.g., a reference parameter weight) for the sampling position in the reference projection format may be identified. An adjustment factor associated with the parameter weight for the sampling position in the reference projection format may be determined. The parameter weight (e.g., adjusted parameter weight) for the sampling position in the target projection format may be calculated. The calculated adjusted parameter weight may be applied to the sampling position in the target projection format when coding the 360-degree video content.