Real-Time Face Clustering via Dynamic Representative Selection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing face recognition systems in video surveillance struggle with scalability and accuracy in real-time face clustering across multiple video streams, particularly due to unknown feature vectors, transitivity issues in similarity measures, and high memory usage, which can lead to inefficient face image matching and clustering.

Innovation Solution

A method for face clustering that uses a hardware processor and memory to compare new images to representative images of clusters, determining similarity scores, merging clusters if multiple matches are found, and dynamically selecting cluster representatives based on utility and time limits, while employing parallel processing and caching to enhance efficiency and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If all face images are stored in memory for comparison, then matching accuracy is improved, but memory usage increases significantly

Engineering Contradiction:
Improvematching accuracyVSAvoidmemory usage
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential representative features of each cluster (representative face images and similarity thresholds) from the complete set of face images, storing only these extracted features in memory rather than all original images. This allows accurate matching by comparing new images against compact cluster representations while dramatically reducing memory consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of storing all face images and searching through them, the patent inverts the approach by pre-processing images into cluster representatives and storing only those. The matching process then works backwards from the new image to find matches against these compressed representations, achieving both accuracy and efficiency.

Inventive Principle:
Principle #13The other way round (Inversion)

2Speed

If face images from multiple video streams are processed in real-time, then responsiveness is improved, but computational complexity increases

Engineering Contradiction:
ImproveresponsivenessVSAvoidcomputational complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent segments the video stream processing into independent parallel operations: face detection, feature extraction, cluster matching, and cluster management. Each segment can be processed independently and in parallel across multiple video streams, reducing overall computational complexity while maintaining real-time responsiveness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary clustering and representative selection on previously processed images before new images arrive. This pre-computation of cluster structures and representatives reduces the computational burden during real-time matching, enabling faster processing of incoming images from multiple streams.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If cluster representatives are updated frequently to maintain accuracy, then matching precision is improved, but processing time increases

Engineering Contradiction:
Improvematching precisionVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements dynamic cluster representative selection where representatives are updated adaptively based on incoming image quality and cluster coherence metrics. High-quality images that better represent the cluster are selected as new representatives, while low-quality updates are deferred. This dynamic approach maintains matching precision without requiring frequent updates, reducing processing time overhead.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS11250244B2Online face clustering
Publication Date: 2022.02.15 NEC CORP
  • US11250244B2 patent drawing
  • US11250244B2 patent drawing
  • US11250244B2 patent drawing

AI summary

Methods and systems for image clustering include matching a new image to a representative image of a cluster. The new image is set as a representative of the cluster with a first time limit. The new image is set as a representative of the cluster with a second time limit, responsive to a determination that the new image has matched at least one incoming image during the first time limit.