Deep fake detector is a plugin for Autopsy that aims to detect deep fakes or even other types of image manipulations. There are two versions of this plugin, one to detect maipulations on photos and another to detect manipulations on videos.

• Sara Ferreira - Department of Computer Science; Faculty of Sciences; University of Porto, Porto, Portugal; [email protected]
• Mário Antunes - Computer Science and Communication Research Centre (CIIC), School of Technology and Management, Polytechnic of Leiria; Leiria; Portugal; [email protected]
  INESC TEC, CRACS; Porto; Portugal
• Manuel E. Correira - Department of Computer Science; Faculty of Sciences; University of Porto, Porto, Portugal; [email protected]
  INESC TEC, CRACS; Porto; Portugal

• Written in Python 3.9
• Can detect both faces and objects
• Features extraction with Discrete Fourier Transform implementation
• Images and videos classification with SVM-based model

To obtain a functional deepfake detection system using Discrete Fourier Transform and Machine Learning, it is necessary a initial step in order to obtain the input data to feed the classification model, which will be used to classify each image as manipulated or legitimate.

Preprocessing consists initially in extracting three to four frames per second from input videos. This was achieved by creating a python script and all the frames extracted are added to the final input dataset. The next step is the features extraction that are made by applying DFT method. This feature extraction phase reads the photos (and frames) through the OpenCV library and further extracts their features. Using this method, exactly fifty features were obtained for each photo, that were then loaded into a new file with the corresponding label (0 for fake photos and 1 for the genuine ones). At the end of preprocessing phase, a fully labeled dataset is available and ready to feed the SVM model.

The processing phase corresponds to the SVM processing. In a first step, the following parameters were chosen: The RBF (Radial basis function) kernel and a regularization parameter of 6.37. This choice took into account the best practices adopted for similar experiments and the comparison with other parameters. The implementation of SVM processing was made through scikit-learn library for Python 3.9.

The model created by SVM at the processing phase is then used to get a prediction for each photo in the testing dataset. The tests were carried on with a 10-fold cross-validation, by splitting the dataset into ten equal parts and using nine for training and one for testing. The dataset is balanced, regarding the number of fake and genuine photos and videos.

For each SVM model evaluation, the results obtained includes confusion matrix, precision and recall; and the calculated prediction that allows us to deduce the probability of an image have been manipulated.

The standalone application architecture matches the Autopsy data source ingest module. The standalone application was developed before the Autopsy module, which gave the possibility to develop and test the method while disregarding the needed compatibility with the Python libraries and with the strict format that is required by Autopsy to the development of new modules.

For more info about datasets click here.

• Install Autopsy
  

• Download the folder for each module

  • DeepFake photo detector
    
  • DeepFake video detector
    

• Unzip the rar and place the folder in the python plugin folder of Autopsy. In order do find that you can go to Autopsy > Tools > Python Plugins.

If you did everything well, now when you can see our plugin in the Autopsy when you do a ingest.

• Ferreira, S., Antunes, M., & Correia, M. E. "Forensic analysis of tampered digital photos"; 25th Iberoamerican Congress on Pattern Recognition (CIARP); May 2021; Porto; Portugal; to be published in Springer Lecture Notes on Computer Science.
  • Paper is available in the proceedings of the conference, at https://ciarp25.org/wp-content/uploads/sites/10/2021/05/CIARP25-Papers.pdf (accessed on 16 June 2021), pp.402-411.
• Ferreira, S., Antunes, M., & Correia, M. E. (2021). Exposing Manipulated Photos and Videos in Digital Forensics Analysis. Journal of Imaging, 7(7), 102. doi:10.3390/jimaging7070102
• Ferreira, S.; Antunes, M.; Correia, M.E. A Dataset of Photos and Videos for Digital Forensics Analysis Using Machine Learning Processing. Data 2021, 6, 87. https://doi.org/10.3390/data6080087