Source code for bob.bio.gmm.algorithm.IVector

#!/usr/bin/env python
# vim: set fileencoding=utf-8 :
# Laurent El Shafey <Laurent.El-Shafey@idiap.ch>

import bob.core
import bob.io.base
import bob.learn.linear
import bob.learn.em

import numpy

from .GMM import GMM
from bob.bio.base.algorithm import Algorithm

import logging
logger = logging.getLogger("bob.bio.gmm")

class IVector (GMM):
  """Tool for extracting I-Vectors"""

  def __init__(
      self,
      # IVector training
      subspace_dimension_of_t,       # T subspace dimension
      tv_training_iterations = 25,   # Number of EM iterations for the JFA training
      update_sigma = True,
      use_whitening = True,
      use_lda = False,
      use_wccn = False,
      use_plda = False,
      lda_dim = 50,
      plda_dim_F  = 50,
      plda_dim_G = 50,
      plda_training_iterations = 50,
      # parameters of the GMM
      **kwargs
  ):
    """Initializes the local GMM tool with the given file selector object"""
    # call base class constructor with its set of parameters
    GMM.__init__(self, **kwargs)

    # call tool constructor to overwrite what was set before
    Algorithm.__init__(
        self,
        performs_projection = True,
        use_projected_features_for_enrollment = True,
        requires_enroller_training = False, # not needed anymore because it's done while training the projector
        split_training_features_by_client = True,

        subspace_dimension_of_t = subspace_dimension_of_t,
        tv_training_iterations = tv_training_iterations,
        update_sigma = update_sigma,
        use_whitening = use_whitening,
        use_lda = use_lda,
        use_wccn = use_wccn,
        use_plda = use_plda,
        lda_dim = lda_dim,
        plda_dim_F  = plda_dim_F,
        plda_dim_G = plda_dim_G,
        plda_training_iterations = plda_training_iterations,

        multiple_model_scoring = None,
        multiple_probe_scoring = None,
        **kwargs
    )

    self.update_sigma = update_sigma
    self.use_whitening = use_whitening
    self.use_lda = use_lda
    self.use_wccn = use_wccn
    self.use_plda = use_plda
    self.subspace_dimension_of_t = subspace_dimension_of_t
    self.tv_training_iterations = tv_training_iterations
    
    self.ivector_trainer = bob.learn.em.IVectorTrainer(update_sigma=update_sigma)
    self.whitening_trainer = bob.learn.linear.WhiteningTrainer()
    
    self.lda_dim = lda_dim
    self.lda_trainer = bob.learn.linear.FisherLDATrainer(strip_to_rank=False)
    self.wccn_trainer = bob.learn.linear.WCCNTrainer()
    self.plda_trainer = bob.learn.em.PLDATrainer()
    self.plda_dim_F  = plda_dim_F
    self.plda_dim_G = plda_dim_G
    self.plda_training_iterations = plda_training_iterations
      


  def _check_ivector(self, feature):
    """Checks that the features are appropriate"""
    if not isinstance(feature, numpy.ndarray) or feature.ndim != 1 or feature.dtype != numpy.float64:
      raise ValueError("The given feature is not appropriate")

[docs] def train_ivector(self, training_stats): logger.info(" -> Training IVector enroller") self.tv = bob.learn.em.IVectorMachine(self.ubm, self.subspace_dimension_of_t, self.variance_threshold) # train IVector model bob.learn.em.train(self.ivector_trainer, self.tv, training_stats, self.tv_training_iterations, rng=self.rng)
[docs] def train_whitener(self, training_features): logger.info(" -> Training Whitening") ivectors_matrix = numpy.vstack(training_features) # create a Linear Machine self.whitener = bob.learn.linear.Machine(ivectors_matrix.shape[1],ivectors_matrix.shape[1]) # create the whitening trainer self.whitening_trainer.train(ivectors_matrix, self.whitener)
[docs] def train_lda(self, training_features): logger.info(" -> Training LDA projector") self.lda, __eig_vals = self.lda_trainer.train(training_features) # resize the machine if desired if self.lda_dim: self.lda.resize(self.lda.shape[0], self.lda_dim)
[docs] def train_wccn(self, training_features): logger.info(" -> Training WCCN projector") self.wccn = self.wccn_trainer.train(training_features)
[docs] def train_plda(self, training_features): logger.info(" -> Training PLDA projector") self.plda_trainer.init_f_method = 'BETWEEN_SCATTER' self.plda_trainer.init_g_method = 'WITHIN_SCATTER' self.plda_trainer.init_sigma_method = 'VARIANCE_DATA' variance_flooring = 1e-5 training_features = [numpy.vstack(client) for client in training_features] input_dim = training_features[0].shape[1] self.plda_base = bob.learn.em.PLDABase(input_dim, self.plda_dim_F, self.plda_dim_G, variance_flooring) bob.learn.em.train(self.plda_trainer, self.plda_base, training_features, self.plda_training_iterations, rng=self.rng)
[docs] def train_projector(self, train_features, projector_file): """Train Projector and Enroller at the same time""" [self._check_feature(feature) for client in train_features for feature in client] train_features_flatten = [feature for client in train_features for feature in client] # train UBM data = numpy.vstack(train_features_flatten) self.train_ubm(data) del data # project training data logger.info(" -> Projecting training data") train_gmm_stats = [[self.project_ubm(feature) for feature in client] for client in train_features] train_gmm_stats_flatten = [stats for client in train_gmm_stats for stats in client] # train IVector logger.info(" -> Projecting training data") self.train_ivector(train_gmm_stats_flatten) # project training i-vectors train_ivectors = [[self.project_ivector(stats) for stats in client] for client in train_gmm_stats] train_ivectors_flatten = [stats for client in train_ivectors for stats in client] if self.use_whitening: # Train Whitening self.train_whitener(train_ivectors_flatten) # whitening and length-normalizing i-vectors train_ivectors = [[self.project_whitening(ivec) for ivec in client] for client in train_ivectors] if self.use_lda: self.train_lda(train_ivectors) train_ivectors = [[self.project_lda(ivec) for ivec in client] for client in train_ivectors] if self.use_wccn: self.train_wccn(train_ivectors) train_ivectors = [[self.project_wccn(ivec) for ivec in client] for client in train_ivectors] if self.use_plda: self.train_plda(train_ivectors) # save self.save_projector(projector_file)
[docs] def save_projector(self, projector_file): # Save the IVector base AND the UBM AND the whitening into the same file hdf5file = bob.io.base.HDF5File(projector_file, "w") hdf5file.create_group('Projector') hdf5file.cd('Projector') self.save_ubm(hdf5file) hdf5file.cd('/') hdf5file.create_group('Enroller') hdf5file.cd('Enroller') self.tv.save(hdf5file) if self.use_whitening: hdf5file.cd('/') hdf5file.create_group('Whitener') hdf5file.cd('Whitener') self.whitener.save(hdf5file) if self.use_lda: hdf5file.cd('/') hdf5file.create_group('LDA') hdf5file.cd('LDA') self.lda.save(hdf5file) if self.use_wccn: hdf5file.cd('/') hdf5file.create_group('WCCN') hdf5file.cd('WCCN') self.wccn.save(hdf5file) if self.use_plda: hdf5file.cd('/') hdf5file.create_group('PLDA') hdf5file.cd('PLDA') self.plda_base.save(hdf5file)
[docs] def load_tv(self, tv_file): hdf5file = bob.io.base.HDF5File(tv_file) self.tv = bob.learn.em.IVectorMachine(hdf5file) # add UBM model from base class self.tv.ubm = self.ubm
[docs] def load_whitener(self, whitening_file): hdf5file = bob.io.base.HDF5File(whitening_file) self.whitener = bob.learn.linear.Machine(hdf5file)
[docs] def load_lda(self, lda_file): hdf5file = bob.io.base.HDF5File(lda_file) self.lda = bob.learn.linear.Machine(hdf5file)
[docs] def load_wccn(self, wccn_file): hdf5file = bob.io.base.HDF5File(wccn_file) self.wccn = bob.learn.linear.Machine(hdf5file)
[docs] def load_plda(self, plda_file): hdf5file = bob.io.base.HDF5File(plda_file) self.plda_base = bob.learn.em.PLDABase(hdf5file) self.plda_machine = bob.learn.em.PLDAMachine(self.plda_base)
[docs] def load_projector(self, projector_file): """Load the GMM and the ISV model from the same HDF5 file""" hdf5file = bob.io.base.HDF5File(projector_file) # Load Projector hdf5file.cd('/Projector') self.load_ubm(hdf5file) # Load Enroller hdf5file.cd('/Enroller') self.load_tv(hdf5file) if self.use_whitening: # Load Whitening hdf5file.cd('/Whitener') self.load_whitener(hdf5file) if self.use_lda: # Load LDA hdf5file.cd('/LDA') self.load_lda(hdf5file) if self.use_wccn: # Load WCCN hdf5file.cd('/WCCN') self.load_wccn(hdf5file) if self.use_plda: # Load PLDA hdf5file.cd('/PLDA') self.load_plda(hdf5file)
[docs] def project_ivector(self, gmm_stats): return self.tv.project(gmm_stats)
[docs] def project_whitening(self, ivector): whitened = self.whitener.forward(ivector) return whitened / numpy.linalg.norm(whitened)
[docs] def project_lda(self, ivector): out_ivector = numpy.ndarray(self.lda.shape[1], numpy.float64) self.lda(ivector, out_ivector) return out_ivector
[docs] def project_wccn(self, ivector): out_ivector = numpy.ndarray(self.wccn.shape[1], numpy.float64) self.wccn(ivector, out_ivector) return out_ivector
####################################################### ############## IVector projection #####################
[docs] def project(self, feature_array): """Computes GMM statistics against a UBM, then corresponding Ux vector""" self._check_feature(feature_array) # project UBM projected_ubm = self.project_ubm(feature_array) # project I-Vector ivector = self.project_ivector(projected_ubm) # whiten I-Vector if self.use_whitening: ivector = self.project_whitening(ivector) # LDA projection if self.use_lda: ivector = self.project_lda(ivector) # WCCN projection if self.use_wccn: ivector = self.project_wccn(ivector) return ivector
####################################################### ################## Read / Write I-Vectors ####################
[docs] def write_feature(self, data, feature_file): """Saves the feature, which is the (whitened) I-Vector.""" bob.bio.base.save(data, feature_file)
[docs] def read_feature(self, feature_file): """Read the type of features that we require, namely i-vectors (stored as simple numpy arrays)""" return bob.bio.base.load(feature_file)
####################################################### ################## Model Enrollment ###################
[docs] def enroll(self, enroll_features): """Performs IVector enrollment""" [self._check_ivector(feature) for feature in enroll_features] average_ivector = numpy.mean(numpy.vstack(enroll_features), axis=0) if self.use_plda: average_ivector = average_ivector.reshape(1,-1) self.plda_trainer.enroll(self.plda_machine, average_ivector) return self.plda_machine else: return average_ivector
###################################################### ################ Feature comparison ##################
[docs] def read_model(self, model_file): """Reads the whitened i-vector that holds the model""" if self.use_plda: return bob.learn.em.PLDAMachine(bob.io.base.HDF5File(str(model_file)), self.plda_base) else: return bob.bio.base.load(model_file)
[docs] def read_probe(self, probe_file): """read probe file which is an i-vector""" return bob.bio.base.load(probe_file)
[docs] def score(self, model, probe): """Computes the score for the given model and the given probe.""" self._check_ivector(probe) if self.use_plda: return model.log_likelihood_ratio(probe) else: self._check_ivector(model) return numpy.dot(model/numpy.linalg.norm(model), probe/numpy.linalg.norm(probe))
[docs] def score_for_multiple_probes(self, model, probes): """This function computes the score between the given model and several given probe files.""" probe = numpy.mean(numpy.vstack(probes), axis=0) return self.score(model, probe)