Prediction-Based Image Compression for Sharp Edges

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Solution Overview

Problem

Traditional color buffer compression techniques face challenges in handling sharp edges and discontinuities, leading to inefficiencies in energy consumption and data representation, particularly in mobile devices with limited power supply.

Innovation Solution

A prediction-based compression method that calculates differences between neighboring pixel color components, using weighted combinations and guiding bits to efficiently encode and decode color data, avoiding lossless compression across discontinuities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If prediction-based compression is applied across sharp edges in color buffer data, then compression efficiency improves, but prediction accuracy deteriorates due to discontinuities

Engineering Contradiction:
Improvecompression efficiencyVSAvoidprediction accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent segments the prediction process by introducing multiple prediction modes (first prediction mode for smooth regions, second prediction mode for edge regions) and uses a discontinuity detection mechanism to automatically select the appropriate mode. This segmentation allows the system to handle different image regions with different prediction strategies, improving both compression efficiency and prediction accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic prediction mode selection based on real-time discontinuity detection. The system dynamically switches between prediction modes depending on the local image characteristics, using gradient calculations to identify edge regions and adaptively choosing the most suitable prediction approach for each region.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If traditional buffer compression techniques are used, then implementation simplicity is maintained, but energy consumption increases due to inefficient compression

Engineering Contradiction:
Improveimplementation simplicityVSAvoidenergy consumption
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent performs preliminary gradient calculations and discontinuity detections during the compression phase to identify optimal prediction modes and regions. By pre-processing the data to detect edges and discontinuities, the system prepares the information needed for efficient compression, reducing the energy required during actual compression operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes prediction parameters (weights, modes) based on detected image characteristics. By adjusting prediction parameters according to local image features such as gradient magnitude and direction, the system achieves better compression efficiency and reduces energy consumption without requiring complex implementation.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If lossless compression is applied to handle sharp edges, then data accuracy is maintained, but compression ratio deteriorates

Engineering Contradiction:
Improvedata accuracyVSAvoidcompression ratio
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies different compression qualities to different regions of the image. In smooth regions away from edges, more aggressive compression is applied while maintaining accuracy. In edge regions detected through gradient analysis, the system uses specialized prediction modes that preserve sharp transitions. This local quality approach maintains overall data accuracy while improving the compression ratio.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS8824790B2Prediction-based image processing
Publication Date: 2014.09.02 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • US8824790B2 patent drawing
  • US8824790B2 patent drawing
  • US8824790B2 patent drawing

AI summary

A pixel block is compressed by providing a respective color component prediction for each pixel in the block. A difference between color components of two neighboring pixels is calculated and compared to a threshold. If the difference is smaller than the threshold, the prediction is calculated based on a first linear combination of the color components of these two neighboring pixels. However, if the difference exceeds the threshold, a second or third linear combination of the color components of the neighboring pixels is employed in the prediction. A guiding bit associated with the selected linear combination may be used. A prediction error is calculated based on the color component of the pixel and the provided prediction. The compressed block comprises an encoded representation of the prediction error and any guiding bit.