Image Processing Apparatus Skin-Based Color Correction

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Solution Overview

Problem

Existing image processing methods fail to accurately correct color casting in image data due to the lack of consideration for the correlation between skin and high-intensity portions under different light source conditions, leading to suboptimal color correction, especially when capturing images with varying light sources.

Innovation Solution

An image processing apparatus that extracts skin information, separates it into independent components (melanin, hemoglobin, and shading), calculates a bias representing the light source's color information, and performs color correction using a reference bias to match standard light source conditions, thereby correcting color casting effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If characteristic information of light source is obtained by providing separate sensors, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvelight source characteristic informationVSAvoidimaging apparatus structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The image sensor performs dual functions: capturing image data and providing information for light source characteristic estimation. By utilizing the same sensor for both imaging and light source analysis, the patent eliminates the need for separate sensors, thereby reducing device complexity and cost while maintaining measurement precision through software-based spectral analysis of the captured image data

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent replaces the mechanical/optical approach of using separate physical sensors with a computational approach. By analyzing the spectral characteristics of image data captured by the existing image sensor and applying color adaptation algorithms, the system estimates light source characteristics without additional hardware, substituting computational processing for physical measurement devices

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If skin portion and high-intensity portion are extracted without considering correlation, then ease of operation is improved, but manufacturing precision of color correction deteriorates

Engineering Contradiction:
Improveskin and high-intensity portion extractionVSAvoidcolor correction accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent implements feedback by using the extracted skin portion information to guide and refine the extraction of high-intensity portions. The system analyzes the spatial and spectral relationship between skin regions and bright regions, using skin color characteristics as a reference to identify and correct color casting in high-intensity areas, thereby improving color correction precision while maintaining operational simplicity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies different processing strategies to different regions of the image based on their local characteristics. Skin portions are extracted and analyzed with specific colorimetric methods, while high-intensity portions are processed separately with consideration of their spatial relationship to skin regions. This localized approach allows the system to maintain ease of operation through automated region detection while achieving precise color correction by tailoring processing to each region's specific needs

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2890110B1Image processing apparatus and image processing method
Publication Date: 2018.11.21 RICOH CO LTD
  • EP2890110B1 patent drawingFigure 1
  • EP2890110B1 patent drawingFigure 2
  • EP2890110B1 patent drawingFigure 3A~3B

AI summary

An image processing apparatus includes a skin information obtaining unit that extracts a skin area from an image and obtains skin information from the skin area; an independent component extracting unit that extracts independent components constituting the skin area from the skin information; and a bias calculation unit that calculates, based on the independent components, a bias representing color information of a light source used to illuminate the skin area when the image is captured.