RGB Pixel Selection for Efficient Face Detection

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Solution Overview

Problem

Existing image processing algorithms for mobile devices are computationally intensive, making them inefficient for tasks like face detection and skin tone recognition due to limited processing resources.

Innovation Solution

The method involves preprocessing digital images by selecting pixels in the RGB color space where the red component is the highest and blue component is the lowest, identifying regions of orange hue, and calculating a chroma value to determine potential human skin areas, allowing for efficient face detection and skin tone recognition without transforming color spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing image processing algorithms are used for face detection and skin tone recognition, then processing accuracy is maintained, but computational complexity increases and processing speed decreases

Engineering Contradiction:
Improveface detection accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The image processing is segmented into distinct stages: initial skin tone detection using simple color thresholding, followed by selective application of complex face detection algorithms only to regions containing detected skin tones. This segmentation allows the system to maintain accuracy while reducing overall computational complexity by avoiding unnecessary processing of non-skin regions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary skin tone detection using simple color space thresholding before performing computationally intensive face detection. By pre-identifying regions with skin-tone colors in the image, the system prepares a reduced set of candidate regions that require full face detection processing, thereby maintaining accuracy while reducing computational burden.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If existing image processing algorithms are used for face detection, then detection accuracy is maintained, but processing time increases

Engineering Contradiction:
Improveface detection accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The processing workflow is divided into a fast preliminary stage (color-based skin tone detection) and a detailed stage (face detection). This time-segmented approach ensures that computationally intensive operations are performed only on small subsets of the image, dramatically reducing total processing time while maintaining detection accuracy through the two-stage verification process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary filtering of image regions based on skin-tone color detection before applying time-consuming face detection algorithms. This preliminary action eliminates the need to process entire images or non-relevant regions, reducing processing time by focusing computational resources only on areas with potential face candidates.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If full image processing is performed for skin tone detection, then detection accuracy is maintained, but energy consumption increases

Engineering Contradiction:
Improveskin tone detection accuracyVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts and processes only the color information relevant to skin tone detection from the image data, rather than performing full image processing. By extracting and analyzing only the chrominance components (U and V in YUV color space) that carry skin-tone information, the system maintains detection accuracy while significantly reducing energy consumption compared to processing all image data.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent transforms the image data from RGB to YUV color space and selectively processes only the U and V chrominance parameters for skin tone detection, ignoring the luminance (Y) component. This parameter selection and transformation approach maintains skin tone detection accuracy while reducing the amount of data processed and the energy required for computation.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If color space transformation is performed for orange hue detection, then detection accuracy is improved, but computational complexity increases

Engineering Contradiction:
Improveorange hue detection accuracyVSAvoidcolor space transformation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the color space representation from RGB to YUV and selectively uses the U and V parameters for orange hue detection. This parameter transformation provides accurate color discrimination for skin tone detection while avoiding the complexity of more sophisticated color space transformations, achieving a balance between accuracy and computational simplicity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8660323B2Image Preprocessing
Publication Date: 2014.02.25 APPLE INC
  • US8660323B2 patent drawing
  • US8660323B2 patent drawing
  • US8660323B2 patent drawing

AI summary

A method performed by a software process executing on a computer system includes selecting a first set of pixels in a digital image in the RGB color space. The pixels are selected such that, for each pixel in the set, a red component is a highest value component and a blue component is a lowest value component. The method also includes identifying at least a subset of the first set as a region of orange hue in the digital image.