FL-Net Fringe Line Detection and Phase Unwrapping in InSAR

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Solution Overview

Problem

Traditional fringe line detection algorithms in interferometric synthetic aperture radar (InSAR) data processing are sensitive to noise, leading to incorrect phase unwrapping results due to destruction or creation of fringe lines.

Innovation Solution

A fringe line detection and phase unwrapping method based on a flow net (FL-Net) convolutional neural network, which includes constructing the FL-Net network, detecting fringe lines, performing circulation and path integrals to repair and unwrap the lines, and identifying error points to eliminate noise-induced errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional fringe line detection algorithms are used, then the processing method is simple, but noise destroys fringe lines or produces new fringe lines leading to wrong phase unwrapping results

Engineering Contradiction:
Improvephase unwrapping accuracyVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical/mathematical fringe line detection algorithms with a deep learning-based convolutional neural network system. The neural network automatically learns fringe line patterns from training data and performs detection without relying on hand-crafted algorithms, thereby improving robustness against noise while maintaining detection capability.

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

Solution Approach 2:

The patent implements preliminary training of the convolutional neural network using labeled fringe line data before actual detection. This preliminary action allows the system to learn optimal detection features and patterns in advance, enabling it to handle noisy conditions effectively during the actual phase unwrapping process.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If deep learning-based fringe line detection is used, then noise robustness is improved, but computational complexity and processing time increase

Engineering Contradiction:
Improvenoise robustnessVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The computationally intensive training phase is performed in advance during system setup, allowing the model to learn optimal detection parameters. During actual runtime, the trained model performs rapid inference on new data, separating the heavy computational burden from the time-critical detection process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses a trained neural network model that can be copied and deployed multiple times. Once trained on comprehensive data, the model serves as a reusable component that provides consistent, noise-robust detection without requiring retraining for each new dataset, significantly reducing processing time for subsequent operations.

Inventive Principle:
Principle #26Copying

Data Source

PatentUS20250022107A1Fringe line detection and phase unwrapping method and system based on FL-net convolutional neural network
Publication Date: 2025.01.16 UNIV OF ELECTRONICS SCI & TECH OF CHINA
  • US20250022107A1 patent drawing
  • US20250022107A1 patent drawing
  • US20250022107A1 patent drawing

AI summary

Provided is a fringe line detection and phase unwrapping method and system based on an FL-Net convolutional neural network. The method includes: constructing the FL-Net convolutional neural network; detecting fringe lines of an input image by using the FL-Net convolutional neural network to obtain an image with detected fringe lines; performing circulation integral on the detected fringe lines to repair the detected fringe lines to thereby obtain an image with repaired fringe lines; performing path integral on the repaired fringe lines to unwrap the repaired fringe lines to thereby obtain an image with unwrapped fringe lines; and identifying error points of the unwrapped fringe lines by using the FL-Net convolutional neural network; and processing the error points. Specifically, an HDC method is used to replace a down-sampling method to avoid the loss of resolution, and residual connection is used to prevent the network from being too deep.