Image Processing Device Skin Color Detection

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Solution Overview

Problem

Existing image processing methods struggle to accurately discern skin color regions due to variations in skin tone among different races or individuals, often leading to false color determination, and broadening the color range to accommodate these differences can result in non-skin colors being incorrectly identified as skin colors.

Innovation Solution

An image processing device that designates specific regions within an image, calculates hue angles and color space coordinates, and extracts similar color regions based on differences between reference and pixel values, using a combination of hue angle, color space coordinates, and chromaticness index to accurately identify skin color regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a predetermined hue range of skin color is used for detection, then the detection method is simple, but skin color regions cannot be accurately discerned due to racial or individual differences

Engineering Contradiction:

Improvedetection method simplicityVSAvoidskin color region detection accuracy

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent changes the detection parameters from fixed predetermined hue ranges to dynamically calculated reference hue angles and reference color space coordinates based on actual image content. This allows the detection criteria to adapt to different skin tones while maintaining a systematic detection approach.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary calculation of reference hue angles and reference color space coordinates from a designated specific region before extracting similar color regions throughout the entire image. This preliminary action establishes accurate reference values that account for racial or individual skin color differences.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If the color range is broadened to encompass skin color variations, then racial or individual differences are accommodated, but non-skin colors are wrongly determined as skin colors

Engineering Contradiction:

Improveskin color variation coverageVSAvoidfalse color determination rate

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent transforms the detection approach by calculating reference values (hue angles and color space coordinates) from actual image data rather than using fixed predetermined ranges. This dynamic parameter adjustment maintains adaptability to different skin tones while preventing false identification of non-skin colors.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical approach of fixed hue range comparison with a more sophisticated system that calculates reference values based on actual image content and uses multiple parameters (hue angle, color space coordinates) for more accurate discrimination.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If multiple parameters (hue angle, color space coordinates, chromaticness index) are used for detection, then detection accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvesimilar color region extraction accuracyVSAvoiddetection system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the detection process into distinct functional units: a region designating unit for selecting the specific region, a hue angle calculating unit for computing hue angles, a color space coordinates calculating unit for computing color coordinates, and a region extracting unit for final extraction. This segmentation manages complexity through modular organization.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a multi-functional detection system where the same computational framework (calculating reference values and comparing parameters) can detect various similar color regions regardless of skin tone variations, making the system universally applicable to different racial or individual skin colors.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS9858680B2Image processing device and imaging apparatus

Publication Date: 2018.01.02 CANON KK

AI summary

An image processing device extracts a similar color region from an image, based on at least a difference between a reference hue angle calculated based on a hue angle of pixels or small regions within a specific region of the image and the hue angle within the specific region, and a color difference between reference color space coordinates calculated based on color space coordinates of the pixels or small regions within the specific region and the color space coordinates within the specific region.