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mediapipe/mediapipe/model_maker/python/vision/image_classifier/dataset.py
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# Copyright 2022 The MediaPipe Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Image classifier dataset library."""
import os
import random
import tensorflow as tf
from mediapipe.model_maker.python.core.data import classification_dataset
from mediapipe.model_maker.python.vision.core import image_utils
class Dataset(classification_dataset.ClassificationDataset):
"""Dataset library for image classifier."""
@classmethod
def from_folder(
cls,
dirname: str,
shuffle: bool = True) -> classification_dataset.ClassificationDataset:
"""Loads images and labels from the given directory.
Assume the image data of the same label are in the same subdirectory.
Args:
dirname: Name of the directory containing the data files.
shuffle: boolean, if true, random shuffle data.
Returns:
Dataset containing images and labels and other related info.
Raises:
ValueError: if the input data directory is empty.
"""
data_root = os.path.abspath(dirname)
# Assumes the image data of the same label are in the same subdirectory,
# gets image path and label names.
all_image_paths = list(tf.io.gfile.glob(data_root + r'/*/*'))
all_image_size = len(all_image_paths)
if all_image_size == 0:
raise ValueError('Image size is zero')
if shuffle:
# Random shuffle data.
random.shuffle(all_image_paths)
label_names = sorted(
name for name in os.listdir(data_root)
if os.path.isdir(os.path.join(data_root, name)))
all_label_size = len(label_names)
index_by_label = dict(
(name, index) for index, name in enumerate(label_names))
all_image_labels = [
index_by_label[os.path.basename(os.path.dirname(path))]
for path in all_image_paths
]
path_ds = tf.data.Dataset.from_tensor_slices(all_image_paths)
image_ds = path_ds.map(
image_utils.load_image, num_parallel_calls=tf.data.AUTOTUNE
)
# Load label
label_ds = tf.data.Dataset.from_tensor_slices(
tf.cast(all_image_labels, tf.int64))
# Create a dataset if (image, label) pairs
image_label_ds = tf.data.Dataset.zip((image_ds, label_ds))
tf.compat.v1.logging.info(
'Load image with size: %d, num_label: %d, labels: %s.', all_image_size,
all_label_size, ', '.join(label_names))
return Dataset(
dataset=image_label_ds, label_names=label_names, size=all_image_size
)