Face Replacement Database Creation Using 3D Vector Angle Estimation

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Solution Overview

Problem

Conventional face replacement techniques are cumbersome and time-consuming, requiring manual marking of feature points, are limited to static images, and often result in unnatural visual perception due to color differences and complex angle estimation processes.

Innovation Solution

A method for creating a face replacement database by estimating a 3D vector angle from a 2D face image, using detected corners of the eyes and mouth to form a quadrilateral, converting vertices to 3D coordinates, and matching these with a feature vector model to determine the rotation angle, allowing for automatic and precise dynamic image replacement with edge feathering for natural color adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual marking of feature points is used to calculate replacement regions and angles, then the replacement accuracy for static images can be achieved, but the operation becomes time-consuming and inconvenient for users

Engineering Contradiction:
Improvefeature point detection accuracyVSAvoidmanual operation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system automatically detects feature points (corners of eyes and mouth) and calculates replacement parameters without user intervention. The computer vision algorithm processes the input image to identify key facial landmarks and computes the replacement region and rotation angle automatically, eliminating the need for manual marking while maintaining high precision

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The manual mechanical process of marking feature points is replaced by an automated computer vision system that uses image processing algorithms to detect facial features and calculate geometric parameters, significantly reducing operation time while preserving measurement accuracy

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

2Adaptability or versatility

If conventional face replacement technique is applied, then single static image replacement can be achieved, but it is difficult to apply for dynamic images

Engineering Contradiction:
Improveimage type compatibilityVSAvoidreplacement accuracy
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system is designed to handle both static and dynamic images by processing each frame independently. For video inputs, the algorithm extracts feature points and calculates replacement parameters for each frame, enabling dynamic image replacement while maintaining consistency with the original conventional method's accuracy for static images

Inventive Principle:
Principle #15Dynamics

3Productivity

If simple replacement method is used, then processing speed can be improved, but color difference occurs at the boundary resulting in unnatural visual perception

Engineering Contradiction:
Improveimage replacement speedVSAvoidcolor boundary precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system applies different processing strategies to different regions: the central replacement region uses direct image substitution for speed, while the boundary regions apply color matching and blending techniques to ensure natural transitions. This localized quality adjustment eliminates color differences at boundaries while maintaining overall processing efficiency

Inventive Principle:
Principle #3Local quality

4Measurement precision

If complicated face angle estimation method is used, then estimation accuracy can be improved, but computation time increases significantly

Engineering Contradiction:
Improveface angle estimation accuracyVSAvoidcomputation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system extracts only the essential feature points (corners of eyes and mouth) needed for angle estimation, rather than using complex comprehensive facial landmark detection. By selecting and using only the critical subset of features, the system achieves sufficient estimation accuracy with significantly reduced computation time

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS9898835B2Method for creating face replacement database
Publication Date: 2018.02.20 MING CHUAN UNIVERSITY
  • US9898835B2 patent drawing
  • US9898835B2 patent drawing
  • US9898835B2 patent drawing

AI summary

A method for creating a face replacement database includes steps of creating a face database for storing a plurality of replaced images with a face image rotation angle by using a method for estimating a 3D vector angle from a 2D face image, and defining a region to be replaced in the replaced image. The method for estimating a 3D vector angle from a 2D face image includes the steps of creating a feature vector template; detecting a corner of eye and mouth in a face image; defining a sharp point in a vertical direction of the quadrilateral plane, and converting the vertices into 3D coordinates; computing the four vectors from the sharp point to the four vertices to obtain a vector set, and matching the vector set with the feature vector model to obtain an angle which is defined as a rotation angle of the input face image.