Parametric Reference Image Transformation for Video Coding
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Solution Overview
Problem
The HEVC video coding standard faces challenges in achieving precise motion prediction due to the use of reference images that are not similar in texture and movement to the current image, leading to poor Inter coding performance.
Innovation Solution
A method is introduced that determines parameters for a parametric function to transform reference images into approximations that are more similar to the current image, using subsets of reference images that are temporally closest to the current image, thereby improving the accuracy of motion prediction and compression performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional reference images are used for inter prediction, then the coding process is simple, but the prediction precision deteriorates when reference images are not similar to the current image
Solution Approach 1:
The patent applies preliminary action by transforming reference images before they are used for prediction. The transformation is performed in advance on the reference images from the first subset to create approximations that better match the current image characteristics, thereby improving prediction precision before the actual coding process begins.
Solution Approach 2:
The patent employs parameter changes by applying a parametric function with determined parameters to transform the reference images. This function modifies the parameters of the reference images to make them more similar to the current image in terms of texture and movement characteristics, resolving the contradiction between simplicity and precision.
2Productivity
If reference images with different texture and movement characteristics are used, then the coding process is faster, but the Inter coding performance deteriorates
Solution Approach 1:
The patent performs preliminary transformation of reference images before they are used in the coding process. By pre-processing the reference images to match current image characteristics, the system maintains faster coding speed while improving the reliability of Inter coding performance through better-matched reference images.
Solution Approach 2:
The patent introduces an intermediary transformation process that acts as a mediator between the original reference images and the current image. This intermediary step creates approximated reference images that bridge the gap between different texture and movement characteristics, maintaining both coding efficiency and performance reliability.
3Quantity of substance
If the current image is coded from temporally distant reference images, then the memory requirements are reduced, but the prediction accuracy deteriorates
Solution Approach 1:
The patent applies parameter changes through a parametric transformation function that adapts temporally distant reference images to better match the current image. This transformation modifies the reference image parameters to compensate for temporal distance, maintaining prediction accuracy while allowing the use of fewer reference images in memory.
Solution Approach 2:
The patent performs preliminary transformation on selected reference images to enhance their similarity to the current image before coding. This pre-processing step ensures that even temporally distant or fewer reference images can provide accurate predictions, reducing memory requirements while maintaining prediction accuracy.
Data Source
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AI summary
The invention relates to a method of coding at least one current image (In), characterized in that it comprises steps of: - determination (C4) of at least one parameter (p') of a predetermining function (Fp), said function being able to transform a first subset (SS) of a set (Sn) of previously decoded reference images into an approximation of a second subset (SC) of images of said set (Sn) of reference images, - application (C6) of said function (Fp) according to the parameter (p') determined to a third subset (SD) of said set (Sn) of reference images, said third subset being different from said first subset, so as to obtain another set (SV) of previously decoded reference images, - coding (C7) of the current image (In) on the basis of said obtained set (SV) of reference images.