Image Decoding Filter Thresholds for Stable Luma-Chroma Quality
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Solution Overview
Problem
Conventional image decoding technologies experience variations in decoded image characteristics and subjective quality due to a reversed large-small relationship between luma and chroma signal threshold values based on internal bit depth, affecting image quality consistency.
Innovation Solution
Implement clipping processing on decoded signals prior to filtering, ensuring the absolute differential value between reference and pixel values is within a predefined threshold, and maintain a fixed large-small relationship between luma and chroma signal thresholds regardless of internal bit depth changes, using linear weighted addition for filtered signal generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If threshold values are defined using mathematical formulas based on internal bit depth, then the filtering process can be implemented, but the large-small relationship between luma and chroma threshold values is reversed at different bit depths, causing decoded image characteristics to vary
Solution Approach 1:
The patent applies parameter changes by adjusting the threshold value definitions based on the signal type (luma or chroma) and the internal bit depth. Different threshold values are selected from predefined sets depending on the bit depth, ensuring that the large-small relationship between luma and chroma thresholds is maintained consistently across different bit depth settings, thereby preventing reversal of the threshold relationship while adapting to different bit depth requirements
2Manufacturing precision
If different threshold values are used for luma and chroma signals based on internal bit depth, then the filtering can be optimized for each signal type, but the relationship between luma and chroma thresholds becomes inconsistent across different bit depths
Solution Approach 1:
The patent applies local quality by defining different threshold values specifically for luma signals and chroma signals based on their respective characteristics and the internal bit depth. The threshold values are selected from predefined sets that are optimized for each signal type, while maintaining the large-small relationship between luma and chroma thresholds consistently across different bit depth settings
Solution Approach 2:
The patent applies dynamics by making the threshold value selection adaptive to the internal bit depth setting. The system dynamically selects appropriate threshold values from predefined sets based on the current bit depth configuration, ensuring that the threshold relationship remains consistent and reliable while adapting to different bit depth requirements
Data Source
AI summary
An image decoding device, includes a filter unit using, as an input, a decoded signal prior to the filtering process and output a filtered decoded signal. The filter unit performs clipping processing on the decoded signal prior to the filtering process such that the absolute value of a differential value between a reference pixel value and a pixel value of the decoded signal prior to the filtering process is less than or equal to a predefined threshold value, and to generate the filtered decoded signal through the linear weighted addition of the value after the clipping processing is performed and the pixel value of the decoded signal prior to the filtering process; and a large-small relationship between the threshold value for a luma signal and the threshold value for a chroma signal are defined such that the large-small relationship is unchanged when an internal bit depth is changed.