Multi-view Video Coding Warping Offset Precision
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Solution Overview
Problem
Multi-view video coding methods face challenges in generating high-quality prediction signals for compression due to inaccuracies in disparity information between views, leading to pixel shift noise and reduced compression efficiency, especially for objects near the camera.
Innovation Solution
The method involves obtaining an optimal warping offset by minimizing the error between a currently coded view image and a warped view image of a front view image, which corrects disparity information and enhances the precision of the warped view image, thereby improving image quality and compression efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If disparity vectors are used for prediction between views, then compression efficiency is improved, but prediction precision deteriorates due to rounding effects
Solution Approach 1:
The patent changes the parameter representation from integer-based disparity vectors to fractional-based sub-pixel offset values. By representing warping offsets with fractional precision (e.g., 1/4 pixel accuracy) instead of integer values, the patent eliminates rounding errors while maintaining compression efficiency through optimized parameter encoding.
Solution Approach 2:
The patent introduces an intermediary warping offset calculation step that acts as a mediator between the front view image and the current view image. This intermediary uses fractional arithmetic to compute precise sub-pixel displacements, serving as a bridge that maintains both compression efficiency and prediction precision.
2Measurement precision
If depth information is added for 3D video coding, then prediction signal quality is improved, but pixel shift noise increases due to rounding effects
Solution Approach 1:
The patent changes the depth information utilization by computing warping offsets with fractional precision based on depth values. Instead of applying integer-based disparity compensation, the patent uses fractional arithmetic to calculate sub-pixel positions, thereby eliminating pixel shift noise while maintaining high prediction signal quality.
Solution Approach 2:
The patent replaces the mechanical integer-based pixel shifting mechanism with a mathematical fractional coordinate system. By substituting discrete pixel manipulation with continuous fractional arithmetic operations, the patent eliminates the inherent rounding effects that cause pixel shift noise.
3Device complexity
If conventional coding standards are used for base view, then coding simplicity is maintained, but warping precision is insufficient for near objects
Solution Approach 1:
The patent segments the coding process into two distinct stages: base view coding using conventional standards and view warping using fractional offset calculation. This segmentation allows the patent to maintain coding simplicity for the base view while applying enhanced precision warping techniques selectively, thereby resolving the contradiction between simplicity and precision.
Solution Approach 2:
The patent applies local quality enhancement by using fractional precision warping offsets specifically for the warping operation, while keeping the base view coding simple and conventional. The enhanced precision is applied locally where needed (in the warping step) without complicating the overall coding structure.
Data Source
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AI summary
Embodiments of the present invention provide multi-view video coding and coding methods and corresponding apparatuses, a coder and a decoder. The multi-view video coding method includes: minimizing an error between a currently coded view image and a warped view image of a front view image to obtain an optimal warping offset; calculating disparity information between the front view image and the currently coded view image by using the optimal warping offset, a camera parameter of a view, and depth image information of the front view image; and calculating the warped view image of the front view image by using the disparity information and the front view image, and predicting a current view image by using the warped view image as a prediction signal. In the embodiments of the present invention, an optimal warping offset is obtained by minimizing an error between a currently coded view image and a warped view image of a front view image, and disparity information is corrected by using the optimal warping offset, so as to enhance precision of the warped view image, thereby improving image quality of a multi-view video.