added DeepPixBiS extactor and corresponding test

bob/learn/pytorch/extractor/image/DeepPixBiS.py

+import numpy as np 
+import torch
+from torch.autograd import Variable
+
+import torchvision.transforms as transforms
+
+from bob.learn.pytorch.architectures import DeepPixBiS
+from bob.bio.base.extractor import Extractor
+
+import logging
+logger = logging.getLogger("bob.learn.pytorch")
+
+class DeepPixBiSExtractor(Extractor):
+  """ The class implementing the DeepPixBiS score computation.
+
+  Attributes
+  ----------
+  network: :py:class:`torch.nn.Module`
+      The network architecture
+  transforms: :py:mod:`torchvision.transforms`
+      The transform from numpy.array to torch.Tensor
+
+  """
+  
+  def __init__(self, transforms = transforms.Compose([transforms.ToTensor(),transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])]), model_file=None, scoring_method='pixel_mean'):
+    """ Init method
+
+    Parameters
+    ----------
+    model_file: str
+      The path of the trained PAD network to load
+    transforms: :py:mod:`torchvision.transforms` 
+      Tranform to be applied on the image
+    scoring_method: str
+      The scoring method to be used to get the final score, 
+      available methods are ['pixel_mean','binary','combined']. 
+    
+    """
+
+    Extractor.__init__(self, skip_extractor_training=True)
+    
+    # model
+    self.transforms = transforms 
+    self.network = DeepPixBiS(pretrained=True)
+    self.scoring_method = scoring_method
+    self.available_scoring_methods=['pixel_mean','binary','combined']
+
+    logger.debug('Scoring method is : {}'.format(self.scoring_method.upper())) 
+
+    if model_file is None:
+      # do nothing (used mainly for unit testing) 
+      logger.debug("No pretrained file provided")
+      pass
+    else:
+
+
+      # With the new training
+      logger.debug('Starting to load the pretrained PAD model')
+
+      try:
+        cp = torch.load(model_file)
+      except:
+        try:
+          cp= torch.load(model_file,map_location=lambda storage,loc:storage) 
+        except:
+          raise ValueError('Could not load the model')
+
+      if 'state_dict' in cp:
+        self.network.load_state_dict(cp['state_dict'])
+      else: ## check this part
+        self.network.load_state_dict(cp)
+
+      logger.debug('Loaded the pretrained PAD model')    
+ 
+    self.network.eval()
+
+  def __call__(self, image):
+    """ Extract features from an image
+
+    Parameters
+    ----------
+    image : 3D :py:class:`numpy.ndarray`
+      The image to extract the score from. Its size must be 3x224x224;
+      
+    Returns
+    -------
+    output : float
+      The extracted feature is a scalar values ~1 for bonafide and ~0 for PAs
+    
+    """
+   
+    input_image = np.rollaxis(np.rollaxis(image, 2),2) # changes from CxHxW to HxWxC
+    input_image = self.transforms(input_image)
+    input_image = input_image.unsqueeze(0)
+    
+    output = self.network.forward(Variable(input_image))
+    output_pixel = output[0].data.numpy().flatten()
+    output_binary = output[1].data.numpy().flatten()
+
+    if self.scoring_method=='pixel_mean':
+      score=np.mean(output_pixel)
+    elif self.scoring_method=='binary':
+      score=np.mean(output_binary)
+    elif self.scoring_method=='combined':
+      score= (np.mean(output_pixel)+np.mean(output_binary))/2.0
+    else:
+      raise ValueError('Scoring method {} is not implemented.'.format(self.scoring_method))
+
+    # output is a scalar score
+
+    return score

bob/learn/pytorch/test/test.py

@@ -535,6 +535,14 @@ def test_extractors():
     output = extractor(data)
     assert output.shape[0] == 1
 
+    # DeepPixBiS
+    from ..extractor.image import DeepPixBiSExtractor
+    extractor = DeepPixBiSExtractor(scoring_method='pixel_mean')
+    # this architecture expects color images of size 3x224x224
+    data = numpy.random.rand(3, 224, 224).astype("uint8")
+    output = extractor(data)
+    assert output.shape[0] == 1
+    
     # MCDeepPixBiS
     from ..extractor.image import MCDeepPixBiSExtractor
     extractor = MCDeepPixBiSExtractor(