Image Coding Device Motion Vector Search Range Adaptation
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Solution Overview
Problem
The MPEG-4 AVC/H.264 compression standard for image coding results in increased computation and power consumption due to larger search ranges for motion vectors, leading to reduced accuracy and lower image quality, especially in cases of significant camera motion like zooming or panning.
Innovation Solution
An image coding device and method that determines a coding method based on a 'coding flag' indicating significant motion, adjusting the search range for motion vectors to reference temporally closer frames, thereby reducing computation and power consumption while enhancing accuracy and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a larger search range is used for motion vectors, then accuracy of motion vector estimation is improved, but computation amount and power consumption increase
Solution Approach 1:
The patent dynamically adjusts the motion vector search range based on the temporal distance between the current picture and reference picture. When temporal distance is large, a larger search range is used to capture significant motion; when temporal distance is small, a smaller search range suffices. This dynamic adaptation resolves the contradiction by matching computational resources to actual motion characteristics rather than using a fixed large range.
Solution Approach 2:
The patent changes the search range parameter based on temporal distance between pictures. By adjusting this critical parameter according to the specific coding situation (temporal distance), the system achieves accurate motion estimation only when necessary, thereby reducing overall computation and power consumption while maintaining estimation accuracy when required.
2Measurement precision
If a larger search range is used for motion vectors, then accuracy of motion vector estimation is improved, but coding speed decreases due to increased computation
Solution Approach 1:
The system dynamically adapts the search range based on temporal distance between current and reference pictures. This dynamic approach ensures high coding speed by using smaller search ranges when temporal distance is small, while still achieving accurate motion estimation when temporal distance is large by expanding the search range only when necessary.
Solution Approach 2:
By changing the search range parameter according to temporal distance, the patent optimizes the balance between estimation accuracy and coding speed. The parameter adjustment ensures that computational resources are allocated efficiently, maintaining high coding speed overall while achieving accurate motion vectors when the situation demands it.
3Use of energy by moving object
If a limited search range is used for motion vectors, then computation amount is reduced, but accuracy of motion vector estimation decreases when significant motion is present
Solution Approach 1:
The patent implements dynamic adjustment of the search range based on temporal distance between pictures. This resolves the contradiction by automatically expanding the search range when temporal distance indicates significant motion is likely, and using a limited range when temporal distance is small, thus avoiding unnecessary computation while maintaining accuracy when needed.
Solution Approach 2:
The system changes the search range parameter based on temporal distance information. This parameter adaptation ensures that computation amount is reduced through limited searching in most cases, while accuracy is preserved by expanding the search range when temporal distance suggests significant motion has occurred.
4Loss of substance
If MPEG-4 AVC/H.264 compression is used, then compression rate is improved, but computation amount and circuit scale increase
Solution Approach 1:
The patent introduces dynamic adjustment of motion vector search ranges based on temporal distance between pictures. This dynamic control reduces the average computation amount required for H.264 compression by adapting the search effort to the actual motion characteristics, thereby reducing circuit scale and complexity while maintaining the high compression rate benefits of H.264.
Solution Approach 2:
By changing the search range parameter according to temporal distance, the patent reduces the overall computational complexity of H.264 compression. This parameter adaptation maintains the high compression efficiency of H.264 while reducing the circuit scale and device complexity by avoiding unnecessarily large search ranges in all cases.
Data Source
AI summary
An image coding device which codes input image data includes a coding flag generation unit which determines whether or not the input image data is image data included in data of a moving picture showing a motion of a predetermined motion amount or greater, and generates coding flag information which indicates a result of the determination. A coding method determination unit determines a coding method in which the input image data references coded image data that the coded image data indicates is the input image data included in the data of the moving picture that is closer to the input image data. An image coding unit compression-codes the input image data using the coding method determined by the coding method determination unit.