Intrinsic Image Segmentation for Face Recognition Shadow Removal

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Solution Overview

Problem

Varying illumination conditions in digital images can interfere with accurate face recognition tasks, causing shadows that prevent computer systems from properly identifying facial features.

Innovation Solution

The method involves using tone mapping and spatio-spectral information to segregate intrinsic images, separating material and illumination aspects, which are then processed to generate intrinsic images that enhance face recognition accuracy by removing strong shadowing effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional face recognition methods are used on images with varying illumination conditions, then the system can process images quickly, but the accuracy of facial feature identification deteriorates due to shadows

Engineering Contradiction:
Improveaccuracy of facial feature identificationVSAvoidshadows cast across face
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent segments the image into two separate intrinsic images: a material image representing reflectance properties and an illumination image representing lighting conditions. This segmentation allows the system to process the material image for face recognition while using the illumination image to correct or remove shadow effects, thereby improving identification accuracy without sacrificing processing speed

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an illumination image as an intermediary component that captures lighting information. This intermediary is used to compute correction factors or masks that are applied to the material image, effectively removing shadow interference while preserving the underlying facial features for accurate recognition

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If illumination correction techniques are applied to remove shadows, then face recognition accuracy improves, but the complexity of the image processing system increases

Engineering Contradiction:
Improveface recognition accuracyVSAvoidimage processing system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the image processing task into distinct components: extracting the material image and illumination image separately. This modular approach allows each component to be processed independently using optimized algorithms, managing system complexity while achieving accurate shadow removal and face recognition

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter representation by working in a transformed space (intrinsic images) rather than the original image space. This parameter transformation simplifies the mathematical operations required for illumination correction, as the separation of material and lighting properties enables more efficient computation despite the increased processing steps

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS8194975B2Use of an intrinsic image in face recognition
Publication Date: 2012.06.05 INNOVATION ASSET COLLECTIVE
  • US8194975B2 patent drawing
  • US8194975B2 patent drawing
  • US8194975B2 patent drawing

AI summary

In an exemplary embodiment of the present invention, an automated, computerized method is provided for processing an image. According to a feature of the present invention, the method comprises the steps of providing an image file depicting an image, in a computer memory, identifying information in the image file relevant to a logical deduction regarding material and illumination aspects of an image and selected from information relevant to spatio-spectral aspects of an image and constituents of color; defining a constraint as a function of the information; and utilizing the constraint in an image segregation operation.