3D Mesh Displacement Coding Using Normal and Tangent Vectors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for calculating displacement coefficients in three-dimensional mesh coding, which involve single component displacement coding, result in reduced accuracy and performance due to discarding displacement values on two components, affecting encoder and decoder efficiency.
Innovation Solution
Implement a decoding and encoding method that applies displacement coefficients in the dimension of specific vectors, such as normal, tangent, or bitangent vectors, to improve accuracy and performance by fitting the original and subdivided meshes in these dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single component displacement coding is adopted to reduce data complexity, then encoding complexity is reduced, but displacement coefficient accuracy deteriorates
Solution Approach 1:
The patent transforms the displacement coefficient representation from a single-component scalar to a multi-component vector in a specific coordinate system. By expressing displacement coefficients in the dimension of specific vectors (normal, tangent, bitangent) rather than single components, the patent maintains higher accuracy while still achieving compression through selective precision control in each vector dimension.
2Quantity of substance
If single component displacement coding is adopted to reduce data size, then bitstream size is reduced, but mesh reconstruction accuracy deteriorates
Solution Approach 1:
The patent applies different precision levels to different components of the displacement coefficient vector. By expressing displacement in the dimension of specific vectors (normal, tangent, bitangent), the patent can allocate precision resources locally to each vector component based on its importance, maintaining high accuracy where needed while reducing precision where less critical, thus optimizing the balance between bitstream size and reconstruction accuracy.
3Manufacturing precision
If displacement coefficients are calculated in three-dimensional domain with all components to improve accuracy, then mesh reconstruction accuracy is improved, but encoding complexity increases
Solution Approach 1:
The patent segments the three-dimensional displacement coefficient into three orthogonal components along specific vectors (normal, tangent, bitangent). This segmentation allows the encoding system to process each component separately with appropriate precision control, reducing overall encoding complexity compared to handling the full 3D vector as a single entity, while maintaining the ability to preserve accuracy through selective component retention.
Data Source
AI summary
A decoding method, encoding method, bitstream, decoder, encoder and storage medium are disclosed. The decoding method includes that: a bitstream is parsed to determine a reconstructed base mesh of a current image, displacement coefficients and a value of first syntax identification information, the reconstructed base mesh is reconstructed based on an original mesh of the current image; a subdivided mesh is determined according to the reconstructed base mesh; and when the value of first syntax identification information represents single component displacement coding, the displacement coefficients are applied to subdivision points in the subdivided mesh in a dimension of a specific vector to obtain a reconstructed mesh, the specific vector includes a normal vector, a tangent vector or a bitangent vector, and the displacement coefficients are determined in the dimension of the specific vector by fitting the original mesh and the subdivided mesh in the dimension of the specific vector.