Contrastive Learning for Color Constancy Robustness

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Solution Overview

Problem

Deep learning-based color constancy methods face challenges in generalizing across different camera sensors and suffer from spurious correlations due to insufficient training data, leading to poor performance under varying illuminants, especially in complex scenes.

Innovation Solution

A contrastive learning method that constructs and utilizes positive and negative pairs of images under different illuminants through data augmentation, mapping representations to a latent space to maximize similarity within pairs sharing the same illuminant and minimize similarity across pairs with different illuminants, thereby learning scene-invariant and illuminant-dependent features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If deep learning-based methods are used for color constancy, then performance on training data is improved, but generalization across different camera sensors deteriorates

Engineering Contradiction:
Improvecolor constancy performanceVSAvoidgeneralization across sensors
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the learning objective from sensor-specific color prediction to sensor-agnostic feature representation. By modifying the loss function to operate in a normalized color space rather than device-dependent RGB values, the model learns parameters that are invariant to sensor characteristics, enabling generalization across different camera sensors while maintaining color constancy performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent separates the color constancy task into two independent components: (1) learning sensor-agnostic feature representations through contrastive learning, and (2) adapting to specific sensors through lightweight sensor-specific layers. This segmentation allows the core color constancy knowledge to be generalized while accommodating sensor-specific variations without compromising either generalization or performance.

Inventive Principle:
Principle #1Segmentation

2Productivity

If conventional learning-free methods are used, then computational efficiency is improved, but performance in complex scenes deteriorates

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidcolor constancy performance
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies partial learning by training only the essential feature extraction components through contrastive learning while keeping the overall architecture lightweight. The model performs contrastive learning on a subset of features that are most critical for color constancy, achieving improved performance in complex scenes while maintaining computational efficiency comparable to learning-free methods.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If learning-based methods are used, then color constancy performance is improved, but susceptibility to spurious correlations increases

Engineering Contradiction:
Improvecolor constancy performanceVSAvoidrobustness to spurious correlations
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent converts the potential harm of spurious correlations into a benefit by using contrastive learning to explicitly identify and eliminate them. The contrastive loss function penalizes the model when it learns correlations that do not reflect true color constancy relationships, thereby transforming the risk of learning wrong patterns into a mechanism for ensuring robust, reliable feature representations that generalize across diverse conditions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS12079306B2Methods and apparatuses of contrastive learning for color constancy
Publication Date: 2024.09.03 MEDIATEK INC
  • US12079306B2 patent drawing
  • US12079306B2 patent drawing
  • US12079306B2 patent drawing

AI summary

A contrastive learning method for color constancy employs a fully-supervised construction of contrastive pairs, driven by a novel data augmentation. The contrastive learning method includes receiving two training images, constructing positive and negative contrastive pairs by the novel data augmentation, extracting representations by a feature extraction function, and training a color constancy model by contrastive learning representations in the positive contrastive pair are closer than representations in the negative contrastive pair. The positive contrastive pair contains images having an identical illuminant while negative contrastive pair contains images having different illuminants. The contrastive learning method improves the performance without additional computational costs. The desired contrastive pairs allow the color constancy model to learn better illuminant feature that are particular robust to worse-cases in data sparse regions.