SAR Image Clutter Segmentation for False Alarm Reduction

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Solution Overview

Problem

Existing radar systems face challenges in accurately identifying targets in SAR images due to high false alarm rates and clutter, particularly in terrains with tree forest coverage, where CFAR techniques often confuse trees for targets, leading to reduced detection and identification effectiveness.

Innovation Solution

A classification and segmentation system that processes SAR image pixels by calculating log-magnitudes, standard deviations, and integrating these values to differentiate between terrain types like forest, grass, and desert, allowing for the suppression of forest clutter and focusing downstream algorithms on grass pixels, thereby reducing false alarms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If CFAR is used for target detection in SAR images, then target detection capability is improved, but false alarm rate increases due to clutter from tree lines

Engineering Contradiction:
Improvetarget detection capabilityVSAvoidfalse alarm rate
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the SAR image into different terrain types (forest, grass, desert) using classification algorithms. By dividing the image into homogeneous regions, the system can apply different processing strategies to each segment, preventing forest clutter from being misclassified as targets while maintaining target detection capability in grass and desert regions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by using terrain-specific detection thresholds and parameters for different segmented regions. Forest regions receive different processing treatment compared to grass or desert regions, optimizing detection performance for each local terrain type while reducing false alarms in forested areas where tree lines create clutter.

Inventive Principle:
Principle #3Local quality

2Device complexity

If CFAR processes all pixels uniformly, then processing simplicity is maintained, but target identification accuracy decreases in mixed terrain

Engineering Contradiction:
Improveprocessing simplicityVSAvoidtarget identification accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces segmentation that divides the image into distinct terrain regions based on pixel classification. This allows the system to maintain relatively simple processing within each homogeneous segment while achieving high overall accuracy through the combination of segmentation and terrain-specific processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes processing parameters based on terrain type. Different threshold values, detection criteria, and algorithmic approaches are applied to different terrain segments (forest vs. grass vs. desert), allowing optimal detection performance for each terrain type without requiring a completely complex unified approach.

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If multiscale segmentation algorithms are used to reduce false alarms, then false alarm rate decreases, but computational complexity increases

Engineering Contradiction:
Improvefalse alarm rateVSAvoidcomputational complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent uses segmentation to group pixels into terrain types, which reduces false alarms by preventing forest clutter from being misidentified as targets. The segmentation approach is designed to be computationally efficient by using straightforward classification criteria and avoiding overly complex multiscale analysis.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by focusing computational resources on specific terrain regions that benefit most from detailed analysis. Rather than applying complex multiscale algorithms uniformly across the entire image, the system applies enhanced processing only where needed based on terrain classification, reducing overall computational complexity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS8977062B2Reduction of CFAR false alarms via classification and segmentation of SAR image clutter
Publication Date: 2015.03.10 RAYTHEON CO
  • US8977062B2 patent drawing
  • US8977062B2 patent drawing
  • US8977062B2 patent drawing

AI summary

The classification and segmentation system of the current invention makes use of information from pixels of an image, namely the magnitude of the pixels, to run specific analytics to classify and segment the image pixels into different groups. This invention includes a system for processing an image, the system including an input device, a processor, a memory and a monitor. The input device is configured to receive image data, where the image data includes pixels and each pixel has a magnitude. The memory has instructions stored in it that, when executed by the processor, cause the processor to run calculations. The calculations include: calculating the log-magnitudes from the magnitudes of at least a plurality of the pixels, calculating standard deviations of the log-magnitudes for subsets of the plurality of pixels and compute an integral of the standard deviations over a desired range. The pixels are classified into different groups based on a value of the integral relative to one or more integral values. In one embodiment, a monitor is configured to display a threshold image, wherein the threshold image includes the different groups of pixels.