Interlaced Picture Coding Using Static Area Information
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Solution Overview
Problem
Conventional picture coding methods for interlaced video signals often degrade picture quality and coding efficiency, especially when a static background is incorrectly identified as having motion due to partial object movement, leading to suboptimal reference field selection.
Innovation Solution
A picture coding apparatus that calculates static area information for each field and selects a reference field based on parity and temporal distance, using this information to improve coding efficiency and picture quality by choosing fields with similar or opposite parity and temporal proximity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reference field selection is based on average motion vector size of each field, then coding efficiency can be optimized for moving areas, but picture quality deteriorates in static areas due to incorrect motion detection
Solution Approach 1:
The picture is divided into multiple areas (e.g., upper and lower portions) and motion analysis is performed separately for each area. This allows the coding apparatus to identify that the upper portion is static while the lower portion contains moving objects, enabling area-specific reference field selection that prevents motion artifacts in static regions while maintaining coding efficiency in moving regions.
Solution Approach 2:
Different reference field selection strategies are applied to different areas of the picture based on their motion characteristics. Static areas use one selection criterion while moving areas use another, allowing optimal picture quality and coding efficiency to be achieved locally in each region rather than applying a uniform approach to the entire picture.
2Manufacturing precision
If all possible fields are detected as candidates and coded to select the best reference field, then coding efficiency and picture quality are improved, but processing volume increases significantly
Solution Approach 1:
Motion analysis and area division are performed in advance before reference field selection. By pre-identifying static and moving areas, the system can narrow down the candidate reference fields for each area, avoiding the need to evaluate all possible fields and thereby reducing processing volume while maintaining picture quality.
3Reliability
If motion detection is performed for the entire picture, then moving objects can be tracked, but static background areas are incorrectly identified as having motion
Solution Approach 1:
The picture is segmented into multiple areas and motion detection is performed independently for each area. This allows the system to correctly identify that the upper portion contains no motion while the lower portion contains moving objects, preventing false motion detection in static background areas.
Solution Approach 2:
Motion detection parameters such as threshold values are adjusted based on the characteristics of each area. For static areas, higher thresholds are used to avoid false positives, while for moving areas, lower thresholds ensure accurate detection, thereby improving overall motion detection reliability.
Data Source
AI summary
A picture coding apparatus includes a static area information calculating unit that calculates static area information indicating a size of a static area of which motion is smaller than a predetermined value for each of fields included in an interlaced picture, a reference field selecting unit that selects, as a reference field to be used to predict a field to be coded, one of a field having of the same parity as a field to be coded and a field having the opposite parity of the field to be coded, among fields previously coded, based on the static area information of the fields previously coded, and a coding unit that codes the field to be coded by using the reference field selected by the reference field selecting unit.