RAW Image Processing Apparatus Adaptive Filter for Coloring Suppression

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Solution Overview

Problem

Conventional image recovery processing for RAW images often results in coloring issues due to mismatched aberration states during image capture and correction, especially when the image recovery filter is optimized for in-focus objects but not for out-of-focus areas, leading to unsatisfactory recovery effects and degradation in image quality.

Innovation Solution

An image processing apparatus and method that incorporates pixel interpolation and color difference calculations to adaptively apply image recovery filters, ensuring accurate correction of aberrations and minimizing coloring by generating appropriate filters based on captured state information, including chromatic difference of magnification correction, to effectively process both in-focus and out-of-focus areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If an image recovery filter optimized for in-focus objects is applied to out-of-focus areas, then the recovery processing can be simplified, but coloring occurs and image quality degrades

Engineering Contradiction:
Improverecovery processing complexityVSAvoidimage quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the image recovery filter adaptive to different focus states. The system dynamically selects or adjusts filter parameters based on whether the subject is in-focus or out-of-focus, allowing the processing to adapt to the captured state rather than using a fixed filter configuration. This resolves the contradiction by enabling simplified processing for in-focus areas while applying appropriate corrections for out-of-focus areas to prevent coloring.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes filter parameters based on the captured state information. Specifically, the system modifies the image recovery filter characteristics according to the focus state (in-focus vs. out-of-focus) and applies chromatic difference of magnification correction only when appropriate. This parameter adaptation allows the system to maintain image quality across different focusing conditions while avoiding unnecessary processing complexity.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If chromatic difference of magnification correction is applied to all images, then color accuracy improves, but processing time and complexity increase

Engineering Contradiction:
Improvecolor accuracyVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary analysis of the captured state information to determine whether chromatic difference of magnification correction is necessary before applying the full processing pipeline. By evaluating the focus state in advance, the system can selectively apply the time-consuming chromatic correction only when needed (for out-of-focus areas), rather than processing all images uniformly. This preliminary assessment reduces unnecessary processing time while maintaining color accuracy where required.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If image recovery processing is applied uniformly to all regions, then processing simplicity is maintained, but coloring occurs in out-of-focus regions

Engineering Contradiction:
Improveprocessing simplicityVSAvoidcolor accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies local quality by treating different regions of the image differently based on their focus state. Instead of uniform processing, the system identifies out-of-focus regions and applies chromatic difference of magnification correction specifically to those areas, while leaving in-focus areas processed with standard recovery filters. This localized approach maintains processing simplicity for the majority of the image while preventing coloring in specific problem areas.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2566161B1Image processing apparatus and method
Publication Date: 2016.02.10 CANON KK
  • EP2566161B1 patent drawingFigure 1
  • EP2566161B1 patent drawingFigure 2
  • EP2566161B1 patent drawingFigure 3

AI summary

An image processing apparatus and image processing method, which enable suppression of coloring that occurs in image recovery processing for a RAW image are disclosed. Pixel interpolation processing is executed for a predetermined reference color component of the RAW image (S201). For each color component other than the reference color component, a first color difference is obtained using a pixel value of the color component and a corresponding pixel value of the reference color component after the pixel interpolation processing (S202). After applying the image recovery processing to each color component, a second color difference is obtained in a similar manner to the first color difference (S206), and a pixel value is corrected according to the difference between the first and second color differences determined before and after the image recovery processing (S208).