Stacked Hourglass Defogging for Local-Global Feature Recovery

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing deep learning-based image defogging methods suffer from low efficiency and poor quality due to the need to estimate a large number of parameters and insufficient richness of features, failing to effectively capture both local and global features.

Innovation Solution

A multi-scale fusion defogging method using a stacked hourglass network with a multi-scale jump connection module and hierarchical attention distillation module to extract and fuse features at different scales, optimizing network structure for improved feature representation and quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If deep learning-based defogging methods are used to directly output defogged images, then the processing speed is improved, but the defogging quality deteriorates due to insufficient feature richness and large number of parameters to estimate

Engineering Contradiction:
Improvedefogging processing speedVSAvoiddefogging image quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent segments the defogging process into multiple parallel convolutional streams operating at different scales (1/2, 1/4, 1/8, 1/16 of original scale). Each stream extracts features independently at its specific scale, avoiding the need to estimate all parameters in a single large network, thus maintaining processing speed while improving feature richness and image quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent adds a scale dimension by processing features at multiple resolutions (different spatial dimensions). The multi-scale feature fusion combines information from 1/2, 1/4, 1/8, and 1/16 scale streams, enriching the feature representation without proportionally increasing parameter count, thereby improving defogging quality while maintaining efficiency.

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

2Device complexity

If a single network is used for defogging, then the device complexity is reduced, but the generalization performance deteriorates due to insufficient feature richness

Engineering Contradiction:
Improvenetwork structure complexityVSAvoiddefogging generalization performance
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent merges multiple convolutional streams at different scales into a unified feature fusion module. The multi-scale features from streams at 1/2, 1/4, 1/8, and 1/16 scales are combined through addition operations, achieving rich feature representation and good generalization performance while keeping the overall network structure relatively simple and manageable.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If multiple parameters are estimated in defogging models, then the image quality is improved, but the computational efficiency deteriorates due to the large number of parameters

Engineering Contradiction:
Improvedefogged image qualityVSAvoiddefogging computational efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies local quality by having different convolutional streams process different spatial scales with appropriate feature extraction. Each stream operates locally at its specific scale with a manageable number of parameters, avoiding the need to estimate all parameters globally at once, thus maintaining computational efficiency while achieving high image quality through multi-scale feature fusion.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS12423786B2Multi-scale fusion defogging method based on stacked hourglass network
Publication Date: 2025.09.23 NANJING UNIV OF POSTS & TELECOMM
  • US12423786B2 patent drawing
  • US12423786B2 patent drawing
  • US12423786B2 patent drawing

AI summary

Disclosed is a multi-scale fusion defogging method based on a stacked hourglass network, including inputting a foggy image into a preset image defogging network; and outputting a fogless image after the foggy image is processed by the image defogging network. The image defogging network includes a 7×7 convolutional layer, a stacked hourglass module, a feature fusion, a multi-scale jump connection module, a 1×1 convolutional layer, a 3×3 convolutional layer, a hierarchical attention distillation module, the 3×3 convolutional layer and the 1×1 convolutional layer connected sequentially.