Local Feature Embedding for Fine-Grained Visual Pattern Recognition

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Solution Overview

Problem

Existing visual pattern recognition systems are inadequate in capturing subtle differences within object categories, particularly for fine-grained recognition tasks such as distinguishing various typefaces and fonts, due to insufficient feature extraction methods.

Innovation Solution

The proposed system employs local feature embedding (LFE) by max pooling local descriptors into a higher dimensional space, recording indices of max pooling coefficients, and using a large-scale classification algorithm based on local feature metric learning and template selection, which allows for efficient generalization to new classes and data with minimal computational cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional feature extraction methods are used, then the system is computationally efficient, but it fails to capture subtle fine-grained differences within object categories

Engineering Contradiction:
Improvefeature extraction precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the feature extraction process into multiple stages: extracting local descriptors from image regions, encoding them into local feature vectors, and then pooling these vectors to form a comprehensive feature representation. This segmentation allows the system to capture fine-grained details at the local level while maintaining overall computational efficiency through structured processing stages.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms local descriptors into local feature vectors through encoding, effectively adding a dimensional transformation layer. This dimensionality change enables the system to represent subtle variations in features more discriminatively, capturing fine-grained differences that would be lost in traditional fixed-length feature representations.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If max pooling local descriptors into higher dimensional space is employed, then fine-grained features are captured accurately, but computational overhead increases

Engineering Contradiction:
Improvefeature discrimination accuracyVSAvoidcomputational overhead
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent applies max pooling to select the most discriminative local feature vectors rather than processing all possible feature combinations. By selectively pooling only the most relevant features (excessive action on key features, partial on others), the system achieves high discrimination accuracy while avoiding the computational burden of processing every possible feature interaction in the higher dimensional space.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent performs preliminary encoding of local descriptors into local feature vectors before the pooling operation. This preliminary action organizes the data in a more efficient representation, making the subsequent max pooling operation more computationally tractable while still capturing the necessary fine-grained information in the higher dimensional space.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If local feature embedding with max pooling is used, then both coarse and fine-grained features are captured, but the system complexity increases

Engineering Contradiction:
Improvefeature representation capabilityVSAvoidprocessing pipeline complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges multiple feature representation capabilities into a unified local feature embedding framework. By combining local descriptor extraction, encoding into local feature vectors, and max pooling operations, the system achieves both coarse and fine-grained feature capture within a single integrated processing pipeline, reducing overall system complexity compared to separate specialized systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The local feature embedding approach serves multiple functions simultaneously: it extracts local patterns, encodes them into discriminative vectors, pools them for robust representation, and captures both coarse and fine-grained features. This multi-functionality reduces the need for separate specialized modules, thereby managing system complexity while enhancing adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Adaptability or versatility

If large-scale classification algorithm with template selection is applied, then generalization to new classes is improved, but training time increases

Engineering Contradiction:
Improvegeneralization capabilityVSAvoidtraining time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent performs preliminary template selection during the training phase, pre-identifying the most discriminative templates for each class. This preliminary action creates a compact set of representative templates that can be quickly applied during classification, significantly reducing the time required for both training and inference while maintaining strong generalization to new classes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts and selects only the most relevant templates from the full template set for each class. By taking out only the essential templates that provide the best discrimination and generalization, the system reduces the computational burden of processing all possible templates, thereby decreasing training time while preserving generalization capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS9141885B2Visual pattern recognition in an image
Publication Date: 2015.09.22 ADOBE INC
  • US9141885B2 patent drawing
  • US9141885B2 patent drawing
  • US9141885B2 patent drawing

AI summary

A system may be configured as an image recognition machine that utilizes an image feature representation called local feature embedding (LFE). LFE enables generation of a feature vector that captures salient visual properties of an image to address both the fine-grained aspects and the coarse-grained aspects of recognizing a visual pattern depicted in the image. Configured to utilize image feature vectors with LFE, the system may implement a nearest class mean (NCM) classifier, as well as a scalable recognition algorithm with metric learning and max margin template selection. Accordingly, the system may be updated to accommodate new classes with very little added computational cost. This may have the effect of enabling the system to readily handle open-ended image classification problems.