Density-Based Sample Selection for Few-Shot Classification

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Solution Overview

Problem

Existing few-shot learning methods face challenges in effectively utilizing limited labeled data for classification tasks, especially in cold-start settings where labeling budgets are restricted, and traditional active learning techniques are unsuited for such scenarios due to reliance on unstable models.

Innovation Solution

A method that involves extracting features from samples, statistically inferring their probability distributions, and actively selecting samples for labeling using log-probability ratios to achieve high accuracy in classification tasks with limited labeling budgets, employing preprocessing techniques like normalization and graph smoothing to enhance feature quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional active learning techniques are used in cold-start settings, then model selection is based on uncertainty or variance reduction, but the model is unstable with zero labeled examples making the approach inapplicable

Engineering Contradiction:
Improveclassification accuracyVSAvoidmodel stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent performs preliminary actions by extracting features from all available unlabeled data and computing density estimates before any labeling occurs. This preliminary feature extraction and density computation enables sample selection to proceed without relying on an initially unstable trained model, resolving the cold-start problem where traditional active learning fails due to model instability with zero labeled examples.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces density estimation as an intermediary mechanism between the available unlabeled data and the sample selection decision. Instead of directly using an unstable model to guide selection, the density estimator serves as a mediator that provides stable probability distributions over classes for each sample, enabling reliable sample selection even when no labeled data is available to train a model.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If a large number of total samples are used with Self-Supervised Learning, then high accuracy is achieved with very limited labeled samples, but the requirement for large total samples cannot be met when data samples are reduced

Engineering Contradiction:
Improveclassification accuracyVSAvoidnumber of total samples
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts and utilizes the underlying probability distribution structure from the available limited samples through density estimation. By extracting the density information that describes how samples are distributed across classes, the method achieves accurate sample selection even with reduced total samples, removing the requirement for large datasets that plagues SSL approaches.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the approach from relying on large sample quantities to relying on accurate density parameter estimation. By computing density parameters (mean and covariance) from the available samples and using these parameters for sample selection, the method achieves high accuracy with limited samples rather than requiring large quantities of data.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If samples are selected uniformly at random in TFSC benchmarks, then the selection process is simple, but the classification accuracy does not reach the high levels achievable with strategic sample selection

Engineering Contradiction:
Improveselection process simplicityVSAvoidclassification accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical random sampling process with a density-based selection mechanism. Instead of relying on random chance to select samples, the system uses computed density estimates to strategically identify and select samples that are most informative for their respective classes, achieving high classification accuracy while maintaining computational efficiency.

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

4Reliability

If traditional machine learning is used requiring large amounts of data, then model training is robust, but the approach is inapplicable when only a few examples are available for training

Engineering Contradiction:
Improvemodel training robustnessVSAvoidamount of training data
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent enables the system to serve itself by computing density estimates from the available unlabeled samples and using these self-computed densities to guide sample selection. This self-service approach eliminates the need for external labeled data or pre-trained models, allowing robust performance with only a few examples available for training.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4475043A1A method for selecting samples in a dataset to be labelled in a classification task, wherein the dataset comprises n samples belonging to k classes and a method for classifying a dataset
Publication Date: 2024.12.11 SCHNEIDER ELECTRIC IND SAS
  • EP4475043A1 patent drawingFigure 1
  • EP4475043A1 patent drawing
  • EP4475043A1 patent drawing

AI summary

A method for selecting samples in a dataset to be labelled in a classification task, wherein the dataset comprises N samples belonging to K classes, comprising the step of: S10: extracting features of the N samples using a feature extractor; S20: statistically inferring a probability distribution of the extracted features in the K classes, to obtain the density of each sample with respect to the K classes distributions; and S30: selecting samples to be labelled using the density.