Landmark-Free Face Attribute Prediction via Learned Spatial Transformations

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Solution Overview

Problem

Traditional face attribute prediction methods face challenges due to reliance on accurate landmark detection, which is inadequate for unconstrained faces with large pose angles, occlusion, or blurriness, and require domain expert knowledge, leading to errors in alignment and attribute prediction.

Innovation Solution

The AFFAIR platform employs an end-to-end learning pipeline that jointly learns spatial transformations and attribute localizations without relying on landmark annotations, using a global transformation network, global representation learning, part localization network, and part representation learning to optimize facial attribute prediction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional face landmark detectors are used for alignment, then near frontal faces achieve good performance, but unconstrained faces with large pose angles, occlusion, and blurriness suffer from unsatisfactory results

Engineering Contradiction:
Improvelandmark detection reliabilityVSAvoidadaptability to unconstrained faces
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent creates a virtual copy of the face by synthesizing a canonical view from the input image through learned spatial transformations. This synthesized face image serves as a reference that can be reliably aligned and compared, bypassing the need for accurate landmark detection on the original unconstrained face image.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical landmark-based alignment system with a learned transformation system. Instead of using handcrafted protocols and landmark detectors, the system learns spatial transformations directly from data, substituting the mechanical alignment process with a neural network-based approach that is more adaptable to various face conditions.

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

2Ease of manufacture

If handcrafted face alignment protocols are used, then domain expert knowledge is utilized, but the process requires dense domain expert knowledge and produces warping artifacts

Engineering Contradiction:
Improveease of implementing alignmentVSAvoidalignment precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces handcrafted alignment protocols with learned spatial transformations. The neural network learns the transformation parameters directly from data, eliminating the need for handcrafted canonical locations and transformation methods. This substitution removes the dependency on dense domain expert knowledge while avoiding the warping artifacts inherent in traditional warping-based alignment.

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

Solution Approach 2:

The patent changes the parameters of the alignment process from fixed handcrafted values to learned parameters. The spatial transformation parameters are optimized through training rather than being manually designed, allowing the system to adapt to different face conditions without requiring expert intervention for each case.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If DAR pipeline with landmark detection is used, then face alignment is achieved, but the alignment process is decoupled from the objective of predicting facial attributes

Engineering Contradiction:
Improveease of performing alignmentVSAvoidattribute prediction reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent merges the alignment process with the attribute prediction objective by using the same learned spatial transformations for both tasks. The transformation parameters are learned jointly with the attribute prediction model, ensuring that the alignment is optimized for the specific goal of predicting facial attributes rather than being a generic preprocessing step.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces feedback by using the attribute prediction objective to guide the learning of spatial transformations. The loss function from attribute prediction is backpropagated to optimize the transformation parameters, creating a feedback loop that ensures the alignment process is explicitly optimized for the prediction task.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS11003892B2Landmark-free face attribute prediction
Publication Date: 2021.05.11 SAP SE
  • US11003892B2 patent drawing
  • US11003892B2 patent drawing
  • US11003892B2 patent drawing

AI summary

Implementations include receiving an input image including a face, processing the input image through a global transformation network to provide a set of global transformation parameters, applying the set of global transformation parameters to the input image to provide a globally transformed image, processing the globally transformed image through a global representation learning network to provide a set of global features, processing the set of global features through a part localization network to provide a set of part localization parameters, applying the set of part localization parameters to the globally transformed image to provide a locally transformed image, processing the locally transformed image through a part representation learning network to provide a set of local features, and outputting a label representing at least one attribute depicted in the input image based on fusing global feature(s) from the set of global features, and local feature(s) from the set of local features.