Face Detection Using Rotated Sample Images and Universal Detectors

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Solution Overview

Problem

Existing face detection methods require extensive preparation of sample image groups for various orientations and directions, leading to inefficient learning and detection processes, especially when dealing with multiple combinations of face directions and orientations.

Innovation Solution

A method that generates face sample image groups by applying mirror reversal processing and 90-degree rotation to initial groups, allowing detectors to learn characteristics for a broader range of orientations and directions, thereby reducing the need for multiple detectors and shortening the learning time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple detectors are generated for each combination of face directions and orientations, then detection accuracy for various face orientations is improved, but preparation time and learning efficiency deteriorate

Engineering Contradiction:
Improvedetection accuracyVSAvoidpreparation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

A single detector is designed to perform multiple functions by detecting faces in various directions and orientations simultaneously. The detector uses multiple detection regions (first detection region for front faces, second detection region for profile faces, third detection region for three-quarter faces) within one unified structure, eliminating the need for separate detectors for each face orientation while maintaining comprehensive detection accuracy.

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

Solution Approach 2:

The detection process is segmented into different detection regions within a single detector. The first detection region handles front faces, the second detection region handles profile faces, and the third detection region handles three-quarter faces. This segmentation allows one detector to efficiently handle multiple face orientations without requiring separate detectors for each type.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If multiple detectors are generated for each combination of face directions and orientations, then detection coverage is improved, but device complexity increases

Engineering Contradiction:
Improvedetection coverageVSAvoidnumber of detectors
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

One universal detector is designed to detect faces in all directions and orientations by incorporating multiple detection regions. The first detection region detects front faces, the second detection region detects profile faces, and the third detection region detects three-quarter faces. This multi-functional design reduces the number of detectors from multiple specialized detectors to a single versatile detector, thereby reducing device complexity while maintaining comprehensive detection coverage.

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

Solution Approach 2:

Multiple detection functions that would traditionally require separate detectors are merged into a single detector. The detector combines the first detection region for front faces, second detection region for profile faces, and third detection region for three-quarter faces into one unified detection apparatus, simplifying the overall system structure while preserving the ability to detect various face orientations.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If learning is carried out for each combination of face directions and orientations, then detection accuracy is improved, but learning efficiency deteriorates

Engineering Contradiction:
Improvedetection accuracyVSAvoidlearning efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The learning process is optimized by training a single universal detector to recognize faces in various directions and orientations simultaneously. The detector learns from training images that include different face orientations (front, profile, three-quarter faces) and develops the capability to detect all these orientations within one learning cycle, rather than requiring separate learning processes for each orientation combination. This significantly improves learning efficiency while maintaining high detection accuracy across all face orientations.

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

Data Source

PatentUS7689034B2Learning method for detectors, face detection method, face detection apparatus, and face detection program
Publication Date: 2010.03.30 FUJIFILM CORP
  • US7689034B2 patent drawing
  • US7689034B2 patent drawing
  • US7689034B2 patent drawing

AI summary

In a method of detecting a face in various directions in a target image with use of detectors, a partial image cut sequentially from the target image is subjected to mirror reversal processing and rotation processing in 90 degree increments for generating reversed/rotated images of the partial image. The detectors of predetermined types judge whether the respective images represent face images in predetermined face directions and orientations. Based on combinations of the types of the detectors and the types of the input images, faces in various face directions and orientations can be judged.