Complex-Valued SAR Object Detection With Phase-Aware Convolution

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Solution Overview

Problem

Existing SAR object detection algorithms primarily utilize real-valued neural networks, neglecting the phase component of SAR data, which contains crucial environmental information, and do not employ complex-valued neural networks effectively.

Innovation Solution

A complex-valued convolutional neural network is used to process SAR data, incorporating both amplitude and phase components, with specific weight applications and loss function terms tailored for SAR image analysis, including batch normalization and dropout layers for improved training efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If real-valued neural networks are used for SAR object detection, then the system is simpler to implement, but the phase component information is lost and detection accuracy deteriorates

Engineering Contradiction:
Improveneural network implementation complexityVSAvoidobject detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transforms the neural network from real-valued to complex-valued, changing the mathematical parameter domain. This allows the network to process both amplitude and phase components of SAR data simultaneously, resolving the contradiction by maintaining implementation simplicity while improving detection accuracy through parameter domain transformation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent adds an imaginary dimension to the neural network processing by introducing complex-valued weights and activations. This dimensional extension allows the network to utilize both real (amplitude) and imaginary (phase) components of SAR data, thereby improving detection accuracy without significantly increasing implementation complexity

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

2Device complexity

If only amplitude data is used for object detection, then the processing is simpler, but crucial environmental information is lost

Engineering Contradiction:
Improvedata processing complexityVSAvoidphase component information
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The complex-valued neural network serves multiple functions simultaneously: it processes amplitude information through the real component and phase information through the imaginary component. This multi-functionality resolves the contradiction by enabling the system to utilize both data types without requiring separate processing pipelines, thus avoiding information loss while maintaining processing efficiency

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

3Measurement precision

If complex-valued neural networks are implemented, then phase information is utilized improving accuracy, but computational complexity increases

Engineering Contradiction:
Improveobject detection accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces traditional real-valued mathematical operations with complex-valued operations in the neural network. This substitution allows the system to process both amplitude and phase information unifiedly, improving detection accuracy while the modular complex convolution operations keep computational complexity manageable through efficient mathematical formulation

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

Data Source

PatentUS12578459B2Object detection from synthetic aperture radar using a complex-valued convolutional neural network
Publication Date: 2026.03.17 NORTHROP GRUMMAN SYSTEMS CORP
  • US12578459B2 patent drawing
  • US12578459B2 patent drawing
  • US12578459B2 patent drawing

AI summary

Systems and methods are provided for object detection. A radar interface receives complex-valued data representing a region of interest from a synthetic aperture radar system. A complex-valued convolutional neural network includes a plurality of convolutional layers and provides an output indicating if objects are present in the region of interest. Each convolutional layer includes a complex-valued kernel that is applied to an input. The kernel includes a first set of weights that is applied to each of real and imaginary components of the input to provide respective first and second convolution products and a second set of weights applied to each of real and imaginary components of the input to provide respective third and fourth convolution products. A difference between the first and fourth convolution products provides a real output component and a sum of the second and third convolution products provides an imaginary output component.