Bacterial Image Classification with Sparse Holographic Features

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Solution Overview

Problem

Existing methods for analyzing the susceptibility of bacteria to antibiotics are lengthy, complex, and require chemical markers that can be cytotoxic, while digital holographic microscopy techniques face challenges in efficient image interpretation and require significant computing resources.

Innovation Solution

A method using digital holographic microscopy to acquire and process images of bacteria, followed by sparse coding and classification using a support vector machine, k-nearest neighbors algorithm, or convolutional neural network, with t-SNE algorithm for dimensionality reduction, to classify bacterial images efficiently and accurately.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If digital holographic microscopy is used to acquire images of bacteria, then non-destructive measurement and rapid analysis are achieved, but efficient image interpretation and classification remain challenging

Engineering Contradiction:
Improveanalysis timeVSAvoidimage processing complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent segments the complex image processing task into distinct stages: hologram acquisition, digital reconstruction to obtain amplitude and phase images, feature extraction from these images, and classification. This segmentation allows each stage to be optimized independently, reducing overall processing complexity while maintaining rapid analysis capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates digital copies (holograms) of the bacterial samples that can be processed computationally without affecting the physical samples. These digital representations allow for repeated analysis and classification without time loss, as the same holographic data can be reconstructed and re-analyzed multiple times.

Inventive Principle:
Principle #26Copying

2Productivity

If sparse coding with dictionary learning is used for feature extraction, then computing time is reduced, but classification accuracy must be maintained

Engineering Contradiction:
Improveprocessing speedVSAvoidclassification accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary action by learning an overcomplete dictionary from training images before the actual classification task. This pre-learned dictionary captures the essential features of bacterial structures, allowing rapid sparse coding during inference without sacrificing accuracy. The dictionary learning phase is performed once, enabling fast processing in subsequent analyses.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the parameter representation by transforming images into sparse codes in a learned dictionary basis rather than using raw pixel values. This parameter transformation reduces the dimensionality and redundancy of the data, enabling faster processing while the classification algorithm operates on the essential features captured in the sparse representation.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If support vector machine or k-nearest neighbors classification is used, then computing resources are reduced, but classification performance must remain high

Engineering Contradiction:
Improvecomputing resource consumptionVSAvoidclassification reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent extracts the most discriminative features through sparse coding with the learned dictionary, separating the essential classification information from redundant data. This extraction allows simpler classification algorithms like SVM and k-NN to operate effectively on the reduced feature set, consuming fewer computing resources while maintaining high classification reliability for bacterial division states.

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables rapid, non-destructive analysis of bacterial responses to antibiotics with reduced computing requirements, providing accurate classification of bacterial division states without the need for lengthy cultures or chemical markers.

Implementation Method 1

It consists of recording a hologram formed by the interference between light waves diffracted by the object under observation and a spatially coherent reference wave

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 2

light waves diffracted by the object under observation

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP4233018B1Method for classifying an input image containing a particle in a sample
Publication Date: 2025.09.03 BIOMERIEUX SA
  • EP4233018B1 patent drawingFigure 1
  • EP4233018B1 patent drawingFigure 2
  • EP4233018B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a method for classifying at least one input image containing a target particle (11a-11f) in a sample (12), the method being characterized in that it involves implementing, via data-processing means (20) of a client (2), steps of: (b) extracting a vector of characteristics of said target particle (11a-11f), said characteristics being numerical coefficients each associated with one elementary image of a set of elementary images each representing a reference particle, such that a linear combination of said elementary images weighted by said coefficients approximates the representation of said target particle (11a-11f) in the input image; (c) classifying said input image depending on said extracted vector of characteristics.