1. Explainability of Deep SAR ATR Through Feature Analysis
- Author
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Alessio Balleri, Carole Belloni, Thomas Merlet, Nabil Aouf, Jean-Marc Le Caillec, Centre for Electronic Warfare, Cranfield University, Defence Academy of the United Kingdom, Shrivenham, SN6 8LA, UK, Département lmage et Traitement Information (IMT Atlantique - ITI), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), City University of London, Equipe Marine Mapping & Metrology (Lab-STICC_M3), Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT), and THALES
- Subjects
Synthetic aperture radar ,Computer science ,Feature extraction ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Aerospace Engineering ,02 engineering and technology ,Convolutional neural network ,law.invention ,Deep Learning ,Automatic target recognition ,0203 mechanical engineering ,[STAT.ML]Statistics [stat]/Machine Learning [stat.ML] ,law ,Electrical and Electronic Engineering ,Radar ,[STAT.CO]Statistics [stat]/Computation [stat.CO] ,Physics::Atmospheric and Oceanic Physics ,Features ,ComputingMilieux_MISCELLANEOUS ,020301 aerospace & aeronautics ,Orientation (computer vision) ,business.industry ,Deep learning ,Pattern recognition ,Explainability ,[SPI.ELEC]Engineering Sciences [physics]/Electromagnetism ,ComputingMethodologies_PATTERNRECOGNITION ,Computer Science::Graphics ,ATR ,Clutter ,Artificial intelligence ,business ,[SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing ,[MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA] ,SAR - Abstract
Understanding the decision-making process of deep learning networks is a key challenge that has rarely been investigated for synthetic aperture radar (SAR) images. In this article, a set of new analytical tools is proposed and applied to a convolutional neural network (CNN) handling automatic target recognition on two SAR datasets containing military targets. First, an analysis of the respective influence of target, shadow, and background areas on classification performance is carried out. The shadow appears to be the least used portion of the image affecting the decision process, compared to the target and clutter, respectively. Second, the location of the most influential features is determined with classification maps obtained by systematically hiding specific target parts and registering the associated classification rate relative to the images to be classified. The location of the image areas without which classification fails is target type and orientation specific. Nonetheless, a strong contribution of specific parts of the target, such as the target top and the areas facing the radar, is noticed. Finally, results show that features are increasingly activated along the CNN depth according to the target type and its orientation, even though target orientation is absent from the loss function.
- Published
- 2021
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