Add util.convert_image_to_format_of

giatools/__init__.py

@@ -1,5 +1,5 @@
 VERSION_MAJOR = 0
 VERSION_MINOR = 1
-VERSION_PATCH = 1
+VERSION_PATCH = 2
 
 VERSION = '%d.%d%s' % (VERSION_MAJOR, VERSION_MINOR, '.%d' % VERSION_PATCH if VERSION_PATCH > 0 else '')

giatools/util.py

@@ -0,0 +1,43 @@
+"""
+Copyright 2017-2024 Leonid Kostrykin, Biomedical Computer Vision Group, Heidelberg University.
+
+Distributed under the MIT license.
+See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
+"""
+
+import numpy as np
+import skimage.util
+
+
+def convert_image_to_format_of(image, format_image):
+    """
+    Convert the first image to the format of the second image.
+    """
+
+    # There is nothing to do with the image if the formats match.
+    if format_image.dtype == image.dtype:
+        return image
+
+    # Convert the image to uint8 if this is the format of the second image.
+    elif format_image.dtype == np.uint8:
+        return skimage.util.img_as_ubyte(image)
+
+    # Convert the image to uint16 if this is the format of the second image.
+    elif format_image.dtype == np.uint16:
+        return skimage.util.img_as_uint(image)
+
+    # Convert the image to int16 if this is the format of the second image.
+    elif format_image.dtype == np.int16:
+        return skimage.util.img_as_int(image)
+
+    # Convert the image to float32 if this is the format of the second image.
+    elif format_image.dtype == np.float32:
+        return skimage.util.img_as_float32(image)
+
+    # Convert the image to float64 if this is the format of the second image.
+    elif format_image.dtype == np.float64:
+        return skimage.util.img_as_float64(image)
+
+    # Other formats are not supported yet (e.g., float16).
+    else:
+        raise ValueError(f'Unsupported image data type: {format_image.dtype}')

tests/test_io.py

@@ -1,4 +1,5 @@
 import unittest
+
 import giatools.io
 
 

tests/test_util.py

@@ -0,0 +1,38 @@
+import itertools
+import unittest
+
+import numpy as np
+import skimage.util
+
+import giatools.util
+
+
+class convert_image_to_format_of(unittest.TestCase):
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        np.random.seed(0)
+        img_uint8 = (np.random.rand(16, 16) * 255).round().astype(np.uint8)
+        self.testdata = [
+            skimage.util.img_as_ubyte(img_uint8),    # uint8
+            skimage.util.img_as_uint(img_uint8),     # uint16
+            skimage.util.img_as_int(img_uint8),      # int16
+            skimage.util.img_as_float32(img_uint8),  # float32
+            skimage.util.img_as_float64(img_uint8),  # float64
+        ]
+
+    def test_self_conversion(self):
+        for img in self.testdata:
+            actual = giatools.util.convert_image_to_format_of(img, img)
+            self.assertIs(actual, img)
+
+    def test_cross_conversion(self):
+        for src_img, dst_img in itertools.product(self.testdata, self.testdata):
+            with self.subTest(f'{src_img.dtype} -> {dst_img.dtype}'):
+                actual = giatools.util.convert_image_to_format_of(src_img, dst_img)
+                self.assertEqual(actual.dtype, dst_img.dtype)
+                self.assertTrue(np.allclose(actual, dst_img, rtol=1e-2))
+
+
+if __name__ == '__main__':
+    unittest.main()