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Unsupervised reconstruction based anomaly detection using a Variational Auto Encoder
Soumick Chatterjee1,2,3, Alessandro Sciarra1,4, Max Dünnwald3,4, Shubham Kumar Agrawal3, Pavan Tummala3, Disha Setlur3, Aman Kalra3, Aishwarya Jauhari3, Steffen Oeltze-Jafra4,5,6, Oliver Speck1,5,6,7, and Andreas Nürnberger2,3,6
1Department of Biomedical Magnetic Resonance, Otto von Guericke University, Magdeburg, Germany, 2Data and Knowledge Engineering Group, Otto von Guericke University, Magdeburg, Germany, 3Faculty of Computer Science, Otto von Guericke University, Magdeburg, Germany, 4MedDigit, Department of Neurology, Medical Faculty, University Hopspital, Magdeburg, Germany, 5German Centre for Neurodegenerative Diseases, Magdeburg, Germany, 6Center for Behavioral Brain Sciences, Magdeburg, Germany, 7Leibniz Institute for Neurobiology, Magdeburg, Germany
The preliminary results indicate that the approach was able to segment candidate anomalous regions while it tends to generate false positives. However, it might be a beneficial tool which can be used to support interactive decision making.
Fig 3. (a) Anomalous MOOD validation data (b) Model does not reconstruct the anomaly in the output (c) Mask representing the difference between the input image and the reconstructed image, indicating the presence of an anomaly or out of distribution sample in the input image. By morphological closing along with binary thresholding, the edges of the anomaly are detected and hence localized
Fig 2. (a) Non-anomalous MOOD data which is the input to our model (b) Reconstructed image obtained as the output of our model (c) Mask representing the difference between the input image and the reconstructed image, with 0 value indicating no anomaly or out of distribution sample in the input image.