data/data_utils_test.py

# coding=utf-8
# Copyright 2021 The Deeplab2 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.

"""Tests for data_utils."""

import io
import numpy as np
from PIL import Image
import tensorflow as tf

from deeplab2.data import data_utils


def _encode_png_image(image):
  """Helper method to encode input image in PNG format."""
  buffer = io.BytesIO()
  Image.fromarray(image).save(buffer, format='png')
  return buffer.getvalue()


class DataUtilsTest(tf.test.TestCase):

  def _create_test_image(self, height, width):
    rng = np.random.RandomState(319281498)
    return rng.randint(0, 255, size=(height, width, 3), dtype=np.uint8)

  def test_encode_and_decode(self):
    """Checks decode created tf.Example for semantic segmentation."""
    test_image_height = 20
    test_image_width = 15
    filename = 'dummy'

    image = self._create_test_image(test_image_height, test_image_width)
    # Take the last channel as dummy label.
    label = image[..., 0]

    example = data_utils.create_tfexample(
        image_data=_encode_png_image(image),
        image_format='png', filename=filename,
        label_data=_encode_png_image(label), label_format='png')

    # Parse created example, expect getting identical results.
    parser = data_utils.SegmentationDecoder(is_panoptic_dataset=False)
    parsed_tensors = parser(example.SerializeToString())

    self.assertIn('image', parsed_tensors)
    self.assertIn('image_name', parsed_tensors)
    self.assertIn('label', parsed_tensors)
    self.assertEqual(filename, parsed_tensors['image_name'])
    np.testing.assert_array_equal(image, parsed_tensors['image'].numpy())
    # Decoded label is a 3-D array with last dimension of 1.
    decoded_label = parsed_tensors['label'].numpy()
    np.testing.assert_array_equal(label, decoded_label[..., 0])

  def test_encode_and_decode_panoptic(self):
    test_image_height = 31
    test_image_width = 17
    filename = 'dummy'

    image = self._create_test_image(test_image_height, test_image_width)
    # Create dummy panoptic label in np.int32 dtype.
    label = np.dot(image.astype(np.int32), [1, 256, 256 * 256]).astype(np.int32)
    example = data_utils.create_tfexample(
        image_data=_encode_png_image(image),
        image_format='png', filename=filename,
        label_data=label.tostring(), label_format='raw')

    parser = data_utils.SegmentationDecoder(is_panoptic_dataset=True)
    parsed_tensors = parser(example.SerializeToString())

    self.assertIn('image', parsed_tensors)
    self.assertIn('image_name', parsed_tensors)
    self.assertIn('label', parsed_tensors)
    self.assertEqual(filename, parsed_tensors['image_name'])
    np.testing.assert_array_equal(image, parsed_tensors['image'].numpy())
    # Decoded label is a 3-D array with last dimension of 1.
    decoded_label = parsed_tensors['label'].numpy()
    np.testing.assert_array_equal(label, decoded_label[..., 0])


if __name__ == '__main__':
  tf.test.main()