Subspace Feature Matching for Efficient Facial Recognition

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Solution Overview

Problem

Current facial recognition techniques using convolutional neural networks (CNNs) are computationally complex, requiring significant memory, processing power, and time, which is a challenge for portable devices that need efficient object recognition.

Innovation Solution

The method involves generating a subspace spanned by multiple representative feature vectors, where a probe feature vector is compared to a reconstructed feature vector within this subspace to facilitate efficient object recognition, using techniques such as convolutional operations and linear combinations of weighting coefficients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If CNN-based facial recognition is used, then recognition accuracy is improved, but computational complexity and processing time increase

Engineering Contradiction:
Improverecognition accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the essential information from the full CNN feature vectors by projecting them onto a lower-dimensional subspace spanned by representative feature vectors. This extraction process retains the most discriminative features while discarding redundant information, thereby reducing computational complexity while maintaining recognition accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the high-dimensional feature space into a manageable subspace by selecting a subset of representative feature vectors that span the essential variation in the data. This segmentation allows the system to perform recognition operations in a reduced-dimensional space, reducing the computational burden on portable devices.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If CNN-based facial recognition is used, then recognition accuracy is improved, but memory requirements and power consumption increase

Engineering Contradiction:
Improverecognition accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts and stores only the essential subspace information represented by a compact set of representative feature vectors, rather than storing and processing complete high-dimensional CNN feature vectors. This extraction significantly reduces memory requirements and subsequent power consumption during recognition operations on portable devices.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary action by pre-computing and storing the subspace basis (representative feature vectors) before actual recognition occurs. This preliminary processing allows the recognition system to operate with reduced computational complexity during real-time operations, thereby reducing power consumption on portable devices.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If full CNN feature vectors are processed, then recognition robustness is improved, but processing time increases

Engineering Contradiction:
Improverecognition robustnessVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the feature representation into a compressed form by projecting full CNN feature vectors onto a lower-dimensional subspace. This segmentation maintains the essential robustness needed for accurate recognition while significantly reducing the number of computations required during processing, thereby reducing processing time.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary subspace representation that mediates between the full CNN feature vectors and the final recognition decision. This intermediary subspace projection acts as a computational bridge that preserves recognition robustness while reducing the time required for processing operations on portable devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS10643063B2Feature matching with a subspace spanned by multiple representative feature vectors
Publication Date: 2020.05.05 QUALCOMM INC
  • US10643063B2 patent drawing
  • US10643063B2 patent drawing
  • US10643063B2 patent drawing

AI summary

Methods, systems, and devices for object recognition are described. A device may generate a subspace based at least in part on a set of representative feature vectors for an object. The device may obtain an array of pixels representing an image. The device may determine a probe feature vector for the image by applying a convolutional operation to the array of pixels. The device may create a reconstructed feature vector in the subspace based at least in part on the set of representative feature vectors and the probe feature vector. The device may compare the reconstructed feature vector and the probe feature vector and recognize the object in the image based at least in part on the comparison. For example, the described techniques may support pose invariant facial recognition or other such object recognition applications.