Pattern-Based Demosaicing for High Dynamic Range Images

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Solution Overview

Problem

Existing image processing techniques struggle to accurately interpolate missing color values in high dynamic range images, particularly in high contrast regions, leading to artifacts and inaccuracies due to the limitations of derivative-based edge detection methods which are ineffective for wide stripes and fail to account for varying luminance across large exposure differences.

Innovation Solution

A pattern-based approach that uses a larger set of pixels to detect edge presence and orientation, selecting appropriate interpolation equations based on the classification of pixel patterns, and employing product term multipliers to calculate missing color values, ensuring accurate interpolation even near image borders and in high contrast areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If derivative-based edge detection methods are used for interpolating missing color values, then the processing speed is maintained, but the accuracy deteriorates in high contrast regions and wide stripe areas

Engineering Contradiction:
Improvecolor value interpolation accuracyVSAvoidedge detection method complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the fundamental parameter of edge detection from derivative-based mathematical operations to pattern-based classification. By analyzing pixel patterns and their spatial relationships rather than computing derivatives, the method achieves accurate edge detection in high contrast regions and wide stripes without the limitations of traditional approaches

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the image processing task into distinct phases: pattern classification, edge detection, orientation determination, and interpolation selection. This segmentation allows each phase to be optimized independently, with pattern-based methods handling edge detection and derivative-based methods handling final interpolation calculations

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If a larger set of pixels is used for pattern-based edge detection, then the accuracy in high contrast regions improves, but the computational complexity increases

Engineering Contradiction:
Improveedge detection accuracyVSAvoidcomputational power required
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent performs preliminary pattern classification on pixel groups before conducting detailed edge detection and interpolation. By pre-identifying edge patterns, orientations, and stripe configurations in high contrast regions, the method reduces the computational burden of subsequent processing steps while maintaining high accuracy

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies different processing strategies to different regions of the image based on local characteristics. In high contrast regions and areas with wide stripes, pattern-based methods with larger pixel sets are used, while in other regions standard interpolation methods suffice, optimizing the balance between accuracy and computational power

Inventive Principle:
Principle #3Local quality

3Ease of operation

If traditional interpolation methods are used, then the processing simplicity is maintained, but zipper artifacts and miss-colored pixels increase

Engineering Contradiction:
Improveinterpolation process simplicityVSAvoidzipper artifacts and miss-colored pixels
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent introduces dynamic selection of interpolation methods based on detected edge patterns and orientations. Rather than applying a single static interpolation approach, the system dynamically chooses from multiple interpolation equations depending on the local image characteristics, reducing artifacts while maintaining processing efficiency

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces pattern classification and edge detection as intermediary steps between image acquisition and final interpolation. These intermediaries analyze pixel patterns to identify edges and orientations, then guide the selection of appropriate interpolation methods, effectively mediating between raw pixel data and final interpolated results to eliminate artifacts

Inventive Principle:
Principle #24Intermediary (Mediator)

4Device complexity

If derivative-based methods are used for edge detection, then the algorithm simplicity is maintained, but the effectiveness fails in wide stripe and high contrast regions

Engineering Contradiction:
Improvealgorithm complexityVSAvoidedge detection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent fundamentally changes the parameter basis for edge detection from mathematical derivatives to pattern recognition. By classifying pixel patterns and their spatial relationships, the method achieves reliable edge detection in wide stripe and high contrast regions where derivative methods fail, without significantly increasing overall algorithm complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the edge detection process into pattern classification and verification phases. By first identifying potential edges through pattern matching and then verifying them through additional checks, the method achieves high reliability in challenging regions while keeping the algorithm structure organized and manageable

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS8463035B2Digital image processing for calculating a missing color value
Publication Date: 2013.06.11 HL KLEMOVE CORP
  • US8463035B2 patent drawing
  • US8463035B2 patent drawing
  • US8463035B2 patent drawing

AI summary

A spectrally mosaiced digital image is provided with missing color data imputed for each pixel. Circuitry is provided that is configured to perform at least a portion of the calculations related to demosaicing a high dynamic range image.