Mirror Loss Neural Networks for Invariant Triplet Embeddings

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Solution Overview

Problem

Existing neural networks struggle to generate embeddings that accurately differentiate similar observations captured by the same modality while being invariant to transformations such as viewpoint, occlusions, motion-blur, and lighting, which hinders their performance in tasks requiring precise environmental characterization.

Innovation Solution

A time-contrastive neural network is trained using a triplet loss function to generate numeric embeddings that are invariant to these transformations by minimizing the distance between anchor and positive embeddings and maximizing the distance between anchor and negative embeddings, utilizing multi-view or temporal observations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a neural network is trained to differentiate similar observations captured by the same modality, then the embedding discrimination capability is improved, but the network becomes sensitive to transformations such as viewpoint, occlusions, motion-blur, and lighting

Engineering Contradiction:
Improveembedding discrimination capabilityVSAvoidinvariance to transformations
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The training data is segmented into triplets consisting of anchor, positive, and negative observations. This segmentation allows the network to learn differentiated features by comparing specific pairs of observations while maintaining invariance through the structured triplet relationship.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mirror loss function dynamically adjusts the loss calculation based on the relative distances between anchor-positive and anchor-negative embeddings. By changing the loss parameter computation to account for transformation variations, the network learns to differentiate observations while remaining invariant to transformations.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If a neural network is trained using traditional loss functions, then the training process is simple, but the generated embeddings fail to accurately characterize environmental states under transformations

Engineering Contradiction:
Improvetraining simplicityVSAvoidembedding accuracy under transformations
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The mirror loss function introduces feedback by computing loss based on the relative positioning of anchor-positive and anchor-negative distances. This feedback mechanism allows the network to automatically adjust its learning to maintain accuracy under transformations without complex architectural changes.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The loss function combines multiple objectives into a composite calculation: it simultaneously considers anchor-positive distance minimization and anchor-negative distance maximization, creating a unified training approach that achieves both differentiation and invariance.

Inventive Principle:
Principle #40Composite materials

3Loss of information

If the network uses multiple channels to learn global and local features, then the feature representation capability is improved, but the device complexity increases

Engineering Contradiction:
Improvefeature representation capabilityVSAvoidnetwork architecture complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The mirror loss function serves multiple functions simultaneously: it differentiates similar observations, maintains invariance to transformations, and works across different observation modalities. This universal approach eliminates the need for separate processing channels for different feature types.

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

Solution Approach 2:

The invention extracts the essential learning objective from complex multi-channel architectures and encapsulates it in the mirror loss function. By taking out the core differentiation and invariance requirements and encoding them in the loss computation, the network achieves equivalent performance with simpler architecture.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3542315B1Mirror loss neural networks
Publication Date: 2025.11.05 GOOGLE LLC
  • EP3542315B1 patent drawingFigure 1
  • EP3542315B1 patent drawingFigure 2
  • EP3542315B1 patent drawingFigure 3

AI summary

This description relates to a neural network that has multiple network parameters and is configured to receive an input observation characterizing a state of an environment and to process the input observation to generate a numeric embedding of the state of the environment. The neural network can be used to control a robotic agent. The network can be trained using a method comprising: obtaining a first observation captured by a first modality; obtaining a second observation that is co-occurring with the first observation and that is captured by a second, different modality; obtaining a third observation captured by the first modality that is not co-occurring with the first observation; determining a gradient of a triplet loss that uses the first observation, the second observation, and the third observation; and updating current values of the network parameters using the gradient of the triplet loss.