Deepfake detection problem from R

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Introduction

Working with video datasets, notably with respect to detection of AI-based pretend objects, could be very difficult as a consequence of correct body choice and face detection. To strategy this problem from R, one could make use of capabilities supplied by OpenCV, magick, and keras.

Our strategy consists of the next consequent steps:

  • learn all of the movies
  • seize and extract photos from the movies
  • detect faces from the extracted photos
  • crop the faces
  • construct a picture classification mannequin with Keras

Let’s rapidly introduce the non-deep-learning libraries we’re utilizing. OpenCV is a pc imaginative and prescient library that features:

Then again, magick is the open-source image-processing library that can assist to learn and extract helpful options from video datasets:

  • Learn video information
  • Extract photos per second from the video
  • Crop the faces from the pictures

Earlier than we go into an in depth rationalization, readers ought to know that there isn’t a have to copy-paste code chunks. As a result of on the finish of the publish one can discover a hyperlink to Google Colab with GPU acceleration. This kernel permits everybody to run and reproduce the identical outcomes.

Information exploration

The dataset that we’re going to analyze is offered by AWS, Fb, Microsoft, the Partnership on AI’s Media Integrity Steering Committee, and numerous teachers.

It comprises each actual and AI-generated pretend movies. The overall dimension is over 470 GB. Nonetheless, the pattern 4 GB dataset is individually accessible.

The movies within the folders are within the format of mp4 and have numerous lengths. Our activity is to find out the variety of photos to seize per second of a video. We often took 1-3 fps for each video.

Word: Set fps to NULL if you wish to extract all frames.

video = magick::image_read_video("aagfhgtpmv.mp4",fps = 2)
vid_1 = video[[1]]
vid_1 = magick::image_read(vid_1) %>% image_resize('1000x1000')

We noticed simply the primary body. What about the remainder of them?

Trying on the gif one can observe that some fakes are very straightforward to distinguish, however a small fraction appears fairly lifelike. That is one other problem throughout information preparation.

Face detection

At first, face areas must be decided by way of bounding packing containers, utilizing OpenCV. Then, magick is used to routinely extract them from all photos.

# get face location and calculate bounding field
library(opencv)
unconf <- ocv_read('frame_1.jpg')
faces <- ocv_face(unconf)
facemask <- ocv_facemask(unconf)
df = attr(facemask, 'faces')
rectX = (df$x - df$radius) 
rectY = (df$y - df$radius)
x = (df$x + df$radius) 
y = (df$y + df$radius)

# draw with pink dashed line the field
imh  = image_draw(image_read('frame_1.jpg'))
rect(rectX, rectY, x, y, border = "pink", 
     lty = "dashed", lwd = 2)
dev.off()

If face areas are discovered, then it is extremely straightforward to extract all of them.

edited = image_crop(imh, "49x49+66+34")
edited = image_crop(imh, paste(x-rectX+1,'x',x-rectX+1,'+',rectX, '+',rectY,sep = ''))
edited

Deep studying mannequin

After dataset preparation, it’s time to construct a deep studying mannequin with Keras. We will rapidly place all the pictures into folders and, utilizing picture mills, feed faces to a pre-trained Keras mannequin.

train_dir = 'fakes_reals'
width = 150L
peak = 150L
epochs = 10

train_datagen = image_data_generator(
  rescale = 1/255,
  rotation_range = 40,
  width_shift_range = 0.2,
  height_shift_range = 0.2,
  shear_range = 0.2,
  zoom_range = 0.2,
  horizontal_flip = TRUE,
  fill_mode = "nearest",
  validation_split=0.2
)


train_generator <- flow_images_from_directory(
  train_dir,                  
  train_datagen,             
  target_size = c(width,peak), 
  batch_size = 10,
  class_mode = "binary"
)

# Construct the mannequin ---------------------------------------------------------

conv_base <- application_vgg16(
  weights = "imagenet",
  include_top = FALSE,
  input_shape = c(width, peak, 3)
)

mannequin <- keras_model_sequential() %>% 
  conv_base %>% 
  layer_flatten() %>% 
  layer_dense(models = 256, activation = "relu") %>% 
  layer_dense(models = 1, activation = "sigmoid")

mannequin %>% compile(
  loss = "binary_crossentropy",
  optimizer = optimizer_rmsprop(lr = 2e-5),
  metrics = c("accuracy")
)

historical past <- mannequin %>% fit_generator(
  train_generator,
  steps_per_epoch = ceiling(train_generator$samples/train_generator$batch_size),
  epochs = 10
)

Reproduce in a Pocket book

Conclusion

This publish exhibits easy methods to do video classification from R. The steps had been:

  • Learn movies and extract photos from the dataset
  • Apply OpenCV to detect faces
  • Extract faces by way of bounding packing containers
  • Construct a deep studying mannequin

Nonetheless, readers ought to know that the implementation of the next steps might drastically enhance mannequin efficiency:

  • extract the entire frames from the video information
  • load completely different pre-trained weights, or use completely different pre-trained fashions
  • use one other know-how to detect faces – e.g., “MTCNN face detector”

Be happy to strive these choices on the Deepfake detection problem and share your ends in the feedback part!

Thanks for studying!

Corrections

When you see errors or wish to counsel modifications, please create a problem on the supply repository.

Reuse

Textual content and figures are licensed below Artistic Commons Attribution CC BY 4.0. Supply code is accessible at https://github.com/henry090/Deepfake-from-R, until in any other case famous. The figures which were reused from different sources do not fall below this license and may be acknowledged by a observe of their caption: “Determine from …”.

Quotation

For attribution, please cite this work as

Abdullayev (2020, Aug. 18). RStudio AI Weblog: Deepfake detection problem from R. Retrieved from https://blogs.rstudio.com/tensorflow/posts/2020-08-18-deepfake/

BibTeX quotation

@misc{abdullayev2020deepfake,
  writer = {Abdullayev, Turgut},
  title = {RStudio AI Weblog: Deepfake detection problem from R},
  url = {https://blogs.rstudio.com/tensorflow/posts/2020-08-18-deepfake/},
  yr = {2020}
}

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