Hierarchical Video Decoding Scale Adjustment for ROI Positional Accuracy
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Solution Overview
Problem
The generation of hierarchically coded data for region of interest (ROI) from entire-area hierarchically coded data leads to an insufficient positional relationship between higher layer and lower layer pixels, affecting prediction correctness.
Innovation Solution
An image decoding apparatus that decodes higher layer data using a parameter set decoding unit to extract scale adjustment information and a predictive image generating unit to derive a reference position on the reference layer, maintaining the same inter-layer scale before and after transformation, thereby ensuring accurate positional correspondence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If hierarchically coded data is generated for region of interest from entire-area hierarchically coded data, then transmission band is reduced, but positional relationship correctness between higher layer and lower layer pixels deteriorates
Solution Approach 1:
The patent applies parameter changes by introducing scale adjustment information that modifies the inter-layer scale used in inter-layer prediction. When ROI extraction is performed, the scale adjustment information changes the scaling factor to maintain correct positional relationships between pixels across layers, thereby resolving the positional accuracy deterioration while preserving transmission band reduction benefits
Solution Approach 2:
The patent introduces an intermediary mechanism (scale adjustment information and extended reference layer offset) that mediates between the ROI extraction process and the inter-layer prediction process. This intermediary ensures that when regions are extracted and transmitted with reduced bandwidth, the positional correspondence between layers is maintained through adjusted scaling parameters
2Productivity
If inter-layer prediction is applied to ROI extracted data, then decoding efficiency is improved, but prediction correctness deteriorates due to scale mismatch
Solution Approach 1:
The patent changes the inter-layer scale parameter based on scale adjustment information when performing inter-layer prediction on ROI extracted data. This parameter modification ensures that the prediction correctness is maintained despite the scale changes introduced by ROI extraction, while still benefiting from improved decoding efficiency through inter-layer prediction
3Manufacturing precision
If scale adjustment information is decoded and applied, then positional relationship correctness is maintained, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and encoding the scale adjustment information and extended reference layer offset during the encoding phase. This preliminary preparation allows the decoding device to simply retrieve and apply these pre-computed parameters without performing complex real-time calculations, thereby maintaining positional accuracy while minimizing the increase in device complexity
Data Source
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AI summary
A hierarchical video decoding apparatus (1) includes a parameter set decoding unit (12) that decodes scale adjustment information, and a predictive image generating unit (1442) that generates a predictive image on the basis of the scale adjustment information.