Dynamic Skin Color Threshold for Face Detection

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Solution Overview

Problem

Current human face detection technologies face challenges in accurately detecting faces due to varying facial expressions, angles, and light conditions, leading to potential false determinations and reduced accuracy.

Innovation Solution

A human face detection and tracking device comprising a photosensitive element, a human face detection unit, a skin color threshold generation unit, and a confidence value unit, which dynamically adjusts skin color thresholds and uses confidence values to improve detection accuracy across different light environments and face sizes, while requiring minimal memory.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a fixed skin color threshold is used for face detection, then the detection process is simple and fast, but the accuracy deteriorates under varying light conditions and facial expressions

Engineering Contradiction:
Improveface detection accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements dynamic skin color threshold adjustment by continuously updating the threshold based on detected face regions and their color characteristics. The system adapts the threshold values in real-time according to lighting conditions and facial features, transforming a static detection mechanism into a dynamic one that maintains high accuracy across varying environments without requiring complex manual calibration

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback mechanisms where detected face regions are used to refine and update the skin color threshold. The feedback loop continuously monitors detection results and adjusts the threshold parameters accordingly, enabling the system to learn from its own performance and improve accuracy iteratively under different lighting conditions and facial expressions

Inventive Principle:
Principle #23Feedback

2Reliability

If multiple face detection algorithms are combined to improve accuracy, then detection reliability improves, but computational complexity and processing time increase

Engineering Contradiction:
Improvedetection reliabilityVSAvoidprocessing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple detection approaches by integrating skin color thresholding with other face detection features into a unified system. Instead of running separate algorithms independently, the system combines their results through a coordinated processing architecture that shares computational resources and leverages complementary strengths, achieving higher reliability without proportionally increasing complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system applies partial action by selectively applying different detection strategies to different regions or conditions. Rather than uniformly applying all possible detection methods across the entire image, the system prioritizes and applies only the most effective algorithms to critical detection tasks, reducing overall computational burden while maintaining high reliability through targeted application of detection techniques

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If the face detection system processes high-resolution images to improve accuracy, then detection precision improves, but memory requirements and processing load increase

Engineering Contradiction:
Improvedetection precisionVSAvoidmemory consumption
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent applies segmentation by dividing the image processing task into multiple stages and regions. The system processes images in segments, focusing computational resources on specific areas where faces are likely to appear, rather than uniformly processing the entire high-resolution image. This segmentation strategy maintains detection precision by examining critical regions in detail while reducing overall memory consumption and processing load through selective analysis

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enhances the accuracy of human face detection and tracking by adapting to changing light conditions and face sizes, reducing false determinations and computational complexity, and efficiently utilizing memory resources.

Implementation Method 1

The image capturing device uses an optical sensor to capture an image, and converts the image into digital signals

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentUS8633978B2Human face detection and tracking device
Publication Date: 2014.01.21 PIXART IMAGING INC
  • US8633978B2 patent drawing
  • US8633978B2 patent drawing
  • US8633978B2 patent drawing

AI summary

A human face detection device includes a photosensitive element, a human face detection unit, and a skin color threshold generation unit. The photosensitive element is used for capturing a first image containing a first human face block. The human face detection unit compares the first image with at least one human face feature, so as to detect the first human face block. The skin color threshold generation unit is used for updating a skin color threshold value according to the detected first human face block. The skin color threshold value is used for filtering the first image signal to obtain a candidate region, the human face detection unit compares the candidate region with the at least one human face feature to obtain the first human face block, and the skin color threshold value determines whether the first human face block detected by the human face detection unit is correct.