Chrominance Inverse Transform Using Luminance Parameters
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Solution Overview
Problem
The existing adaptive primary transform methods do not effectively apply to chrominances, leading to a deterioration in coding efficiency compared to luminance in image processing.
Innovation Solution
An image processing apparatus and method that uses information from luminance to derive and apply inverse orthogonal transforms to chrominance, including adaptive primary transform flags and identifiers, to perform inverse primary horizontal and vertical transforms, thereby curbing the deterioration in coding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If adaptive primary transform is applied only to luminance, then processing complexity for luminance is reduced, but coding efficiency for chrominance deteriorates
Solution Approach 1:
The patent applies the adaptive primary transform configuration from luminance to chrominance by copying the transform index and transform type information. Instead of independently determining transforms for chrominance, the system uses the luminance transform parameters to derive chrominance transform parameters, thereby maintaining coding efficiency for chrominance while avoiding the complexity of separate adaptive transform determination for chrominance components.
2Reliability
If separate adaptive primary transform is applied to chrominance, then coding efficiency for chrominance is improved, but processing load and device complexity increase
Solution Approach 1:
The patent merges the adaptive primary transform processing for luminance and chrominance by using shared transform parameters. The transform index and transform type determined for luminance are reused for chrominance, combining what would otherwise be separate processing paths into a unified approach that reduces overall processing load while maintaining coding efficiency.
Solution Approach 2:
The luminance transform parameters serve multiple functions by being applied to both luminance and chrominance components. This universal usage of transform parameters across different color components eliminates the need for separate adaptive transform determination for chrominance, reducing processing complexity while maintaining effectiveness.
3Measurement precision
If explicit encoding of chrominance transform information is performed, then transform accuracy for chrominance is improved, but bit rate increases
Solution Approach 1:
Instead of explicitly encoding chrominance transform information, the patent copies the transform parameters from luminance to chrominance. The chrominance transform index and transform type are derived from luminance parameters, eliminating the need for separate bit allocation for chrominance transform information while maintaining transform accuracy through the use of effective adaptive parameters.
Data Source
AI summary
There is provided an image processing apparatus and method that can curb deterioration in coding efficiency. An inverse orthogonal transform of chrominance is performed using information regarding the inverse orthogonal transform of chrominance derived on the basis of information regarding an inverse orthogonal transform of luminance. For example, information regarding the orthogonal transform includes an adaptive primary transform flag indicating whether an adaptive primary transform of adaptively selecting one from a plurality of different orthogonal transforms and using the selected transform as a primary transform is to be applied to a transform block to be processed. The present disclosure can be applied to, for example, an image processing apparatus, an image encoding apparatus, an image decoding apparatus, or the like.