def evaluation(self, loader: Loader, epochs: int, imshow=False):
# for debugging purposes
val_accuracy = []
loss = []
for i, (image_batch, seg_batch) in enumerate(loader.get_minibatch(train=False, Aug=False)):
pred = self.call(image_batch.astype(np.float32), training=False)
loss.append(self.loss(seg=seg_batch.astype(np.float32), predictions=pred))
val_accuracy.append(Jaccard_Index(output_batch=pred, gt_batch=seg_batch, visual=imshow))
if i == epochs:
return np.mean(val_accuracy), np.mean(loss)
def evaluation_with_assaf(self, loader: Loader, epochs:int, imshow=True):
# for debugging purposes
seg_measure = SegMeasure()
val_accuracy = []
loss = []
for i, (image_batch, seg_batch) in enumerate(loader.get_minibatch(train=False)):
pred = self.call(image_batch.astype(np.float32), training=False)
loss.append(self.loss(seg=seg_batch.astype(np.float32), predictions=pred))
val_accuracy.append(seg_measure(seg_batch, pred).numpy())
if i == epochs:
return np.mean(val_accuracy), np.mean(loss)
def _train_on_batch(self, image_batch, seg_batch, visual):
sub_image = crop(image_batch=image_batch) # crop function is used to divide the image to tiles
sub_seg = crop(image_batch=seg_batch)
train_acc = []
train_lost = []
for i in range(self.divide_by): # height
for j in range(self.divide_by): # width
train_acc_val, train_loss_val = super(TilesUnet, self).\
_train_on_batch(image_batch=sub_image[:, j + 2 * i, :, :],
seg_batch=sub_seg[:, j + 2 * i, :, :], visual=visual)
train_acc.append(train_acc_val)
train_lost.append(train_loss_val)
return np.mean(train_acc), np.mean(train_lost)
def validation(self, loader: Loader):
"""
validation function that computes the Jaccard Index accuracy on the val data set
:param loader: generator of data
:return: mean of accuracy and loss
"""
seg_measure = SegMeasure()
val_accuracy = []
loss = []
for i, (image_batch, seg_batch) in enumerate(loader.get_minibatch(train=False, Aug=config.Augment)):
pred = self.call(image_batch.astype(np.float32), training=False)
loss.append(self.loss(seg=seg_batch.astype(np.float32), predictions=pred))
if config.use_assaf:
val_accuracy.append(seg_measure(gt=seg_batch, net_output=pred))
else:
val_accuracy.append(Jaccard_Index(output_batch=pred, gt_batch=seg_batch))
if i == config.validation_steps:
return np.mean(val_accuracy), np.mean(loss)
def _train_on_batch(self, image_batch, seg_batch, visual):
mirror = False
if random.random() < config.mirror_threshold:
# we randomly insert mirrored cropped images to the dataset
mirrored_and_cropped_images, mirrored_and_cropped_seg = mirror_image(image_batch=image_batch,
seg_batch=seg_batch,
divide_by=self.divide_by)
mirror = True
train_acc = []
train_lost = []
for i in range(self.divide_by): # height
for j in range(self.divide_by): # width
if mirror:
train_acc_val, train_loss_val = super(TilesUnetMirrored, self). \
_train_on_batch(image_batch=mirrored_and_cropped_images[:, j + 2 * i, :, :],
seg_batch=mirrored_and_cropped_seg[:, j + 2 * i, :, :], visual=visual)
else:
train_acc_val, train_loss_val = super(TilesUnetMirrored, self). \
_train_on_batch(image_batch=image_batch.astype(np.float32),
seg_batch=seg_batch.astype(np.float32), visual=visual)
train_acc.append(train_acc_val)
train_lost.append(train_loss_val)
return np.mean(train_acc), np.mean(train_lost)
def fit(self, logger, loader: Loader, callbacks, epochs:int, steps_per_epoch: int,
val_freq=2, val_steps=4):
"""
training loop that trains the model and controls the augmentation, learning rate and the mirroring capability.
the training loops stops on two conditions:
A. the val accuracy converges over N consecutive trials
B. ran for "epochs" number of epochs
:param logger: logger to log information
:param loader: generator of data
:param callbacks: a dict of tensorboard callbacks and checkpoint callbacks
:param epochs: number of epochs to run
:param steps_per_epoch: number of iterations per epoch
:param val_freq: frequency of epochs to preform validation
:param val_steps: number of steps to preform in validation
"""
Tensorcallback = callbacks['tensorboard']
Checkpoint = callbacks['checkpoint']
info("----- Start Train -----", logger)
best_val_acc = 0
consecutive_trials_val_acc_unchanged = 0
for epoch in range(epochs):
if config.Augment:
if best_val_acc > 0.7: # a threshold for Curriculum learning
config.elastic_threshold = min(0.5, 1 * epoch / epochs) # for the use of elastic threshold
if best_val_acc > 0.65:
config.mirror_threshold = min(0.5, 1 * epoch / epochs) # for the use of mirroring
elif epoch <= 1: # insert randomly augmented images
config.mirror_threshold = 0.5 # for the use of mirroring
config.elastic_threshold = 0.5 # for the use of elastic threshold
train_accuracy = []
train_loss = []
self.optimizer.learning_rate = config.learning_rate_scheduler(epoch) # learning rate scheduler
for iteration, (image_batch, seg_batch) in enumerate(loader.get_minibatch(Aug=config.Augment)):
acc_val, loss_val = self._train_on_batch(image_batch=image_batch, seg_batch=seg_batch,
visual=epoch % 5 == 0 and config.visual)
train_accuracy.append(acc_val)
train_loss.append(loss_val)
if iteration == steps_per_epoch:
break
train_loss_mean = np.mean(train_loss)
train_accuracy_mean = np.mean(train_accuracy)
if epoch % val_freq == 0: # output validation accuracy
val_accuracy, val_loss = self.validation(loader=loader)
info("--- Epoch {}/{}: train accuracy"
" {}, val accuracy {} and loss {} with learning rate {}--- "
.format(epoch, epochs, train_accuracy_mean, val_accuracy, train_loss_mean,
self.optimizer.learning_rate.numpy()), logger)
logs = {'acc': train_accuracy_mean, 'loss': train_loss_mean, 'val_acc': val_accuracy,
'val_loss': val_loss}
Tensorcallback.on_epoch_end(epoch=epoch, logs=logs)
Checkpoint.on_epoch_end(epoch=epoch, logs=logs)
if best_val_acc < val_accuracy:
best_val_acc = val_accuracy
consecutive_trials_val_acc_unchanged = 0
info("-- Epoch {}/{} : best val so far is {} ---".format(epoch, epochs, best_val_acc),
logger)
else:
consecutive_trials_val_acc_unchanged += 1
if consecutive_trials_val_acc_unchanged >= config.converged_threshold: # check if val converged
info("--- Epoch {}/{} : val acc converged for {} consecutive trials, terminating training... ---"
.format(epoch, epochs, config.converged_threshold), logger)
break
Tensorcallback.on_train_end('_')