def _process_image(image: tf.Tensor,
is_training: bool = True,
is_ssl: bool = False,
num_frames: int = 32,
stride: int = 1,
num_test_clips: int = 1,
min_resize: int = 256,
crop_size: int = 224,
num_crops: int = 1,
zero_centering_image: bool = False,
seed: Optional[int] = None) -> tf.Tensor:
"""Processes a serialized image tensor.
Args:
image: Input Tensor of shape [timesteps] and type tf.string of serialized
frames.
is_training: Whether or not in training mode. If True, random sample, crop
and left right flip is used.
is_ssl: Whether or not in self-supervised pre-training mode.
num_frames: Number of frames per subclip.
stride: Temporal stride to sample frames.
num_test_clips: Number of test clips (1 by default). If more than 1, this
will sample multiple linearly spaced clips within each video at test time.
If 1, then a single clip in the middle of the video is sampled. The clips
are aggreagated in the batch dimension.
min_resize: Frames are resized so that min(height, width) is min_resize.
crop_size: Final size of the frame after cropping the resized frames. Both
height and width are the same.
num_crops: Number of crops to perform on the resized frames.
zero_centering_image: If True, frames are normalized to values in [-1, 1].
If False, values in [0, 1].
seed: A deterministic seed to use when sampling.
Returns:
Processed frames. Tensor of shape
[num_frames * num_test_clips, crop_size, crop_size, 3].
"""
# Validate parameters.
if is_training and num_test_clips != 1:
logging.warning(
'`num_test_clips` %d is ignored since `is_training` is `True`.',
num_test_clips)
# Temporal sampler.
if is_training:
# Sampler for training.
if is_ssl:
# Sample two clips from linear decreasing distribution.
image = video_ssl_preprocess_ops.sample_ssl_sequence(
image, num_frames, True, stride)
else:
# Sample random clip.
image = preprocess_ops_3d.sample_sequence(image, num_frames, True,
stride)
else:
# Sampler for evaluation.
if num_test_clips > 1:
# Sample linspace clips.
image = preprocess_ops_3d.sample_linspace_sequence(
image, num_test_clips, num_frames, stride)
else:
# Sample middle clip.
image = preprocess_ops_3d.sample_sequence(image, num_frames, False,
stride)
# Decode JPEG string to tf.uint8.
image = preprocess_ops_3d.decode_jpeg(image, 3)
if is_training:
# Standard image data augmentation: random resized crop and random flip.
if is_ssl:
image_1, image_2 = tf.split(image, num_or_size_splits=2, axis=0)
image_1 = preprocess_ops_3d.random_crop_resize(
image_1, crop_size, crop_size, num_frames, 3, (0.5, 2),
(0.3, 1))
image_1 = preprocess_ops_3d.random_flip_left_right(image_1, seed)
image_2 = preprocess_ops_3d.random_crop_resize(
image_2, crop_size, crop_size, num_frames, 3, (0.5, 2),
(0.3, 1))
image_2 = preprocess_ops_3d.random_flip_left_right(image_2, seed)
else:
image = preprocess_ops_3d.random_crop_resize(
image, crop_size, crop_size, num_frames, 3, (0.5, 2), (0.3, 1))
image = preprocess_ops_3d.random_flip_left_right(image, seed)
else:
# Resize images (resize happens only if necessary to save compute).
image = preprocess_ops_3d.resize_smallest(image, min_resize)
# Three-crop of the frames.
image = preprocess_ops_3d.crop_image(image, crop_size, crop_size,
False, num_crops)
# Cast the frames in float32, normalizing according to zero_centering_image.
if is_training and is_ssl:
image_1 = preprocess_ops_3d.normalize_image(image_1,
zero_centering_image)
image_2 = preprocess_ops_3d.normalize_image(image_2,
zero_centering_image)
else:
image = preprocess_ops_3d.normalize_image(image, zero_centering_image)
# Self-supervised pre-training augmentations.
if is_training and is_ssl:
# Temporally consistent color jittering.
image_1 = video_ssl_preprocess_ops.random_color_jitter_3d(image_1)
image_2 = video_ssl_preprocess_ops.random_color_jitter_3d(image_2)
# Temporally consistent gaussian blurring.
image_1 = video_ssl_preprocess_ops.random_blur(image_1, crop_size,
crop_size, 1.0)
image_2 = video_ssl_preprocess_ops.random_blur(image_2, crop_size,
crop_size, 0.1)
image_2 = video_ssl_preprocess_ops.random_solarization(image_2)
image = tf.concat([image_1, image_2], axis=0)
image = tf.clip_by_value(image, 0., 1.)
return image
def test_sample_ssl_sequence(self):
sampled_seq = video_ssl_preprocess_ops.sample_ssl_sequence(
self._raw_frames, 16, True, 2)
self.assertAllEqual(sampled_seq.shape, (32, 256, 256, 3))