1 files changed, 51 insertions, 0 deletions
diff --git a/src/text_recognizer/util.py b/src/text_recognizer/util.py
new file mode 100644
index 0000000..52fa1e4
--- /dev/null
+++ b/src/text_recognizer/util.py
@@ -0,0 +1,51 @@
+"""Utility functions for text_recognizer module."""
+import os
+from pathlib import Path
+from typing import Union
+from urllib.request import urlopen
+
+import cv2
+import numpy as np
+
+
+def read_image(image_uri: Union[Path, str], grayscale: bool = False) -> np.ndarray:
+    """Read image_uri."""
+
+    def read_image_from_filename(image_filename: str, imread_flag: int) -> np.ndarray:
+        return cv2.imread(str(image_filename), imread_flag)
+
+    def read_image_from_url(image_url: str, imread_flag: int) -> np.ndarray:
+        if image_url.lower().startswith("http"):
+            url_response = urlopen(str(image_url))
+            image_array = np.array(bytearray(url_response.read()), dtype=np.uint8)
+            return cv2.imdecode(image_array, imread_flag)
+        else:
+            raise ValueError(
+                "Url does not start with http, therfore not safe to open..."
+            ) from None
+
+    imread_flag = cv2.IMREAD_GRAYSCALE if grayscale else cv2.IMREAD_COLOR
+    local_file = os.path.exsits(image_uri)
+    try:
+        image = None
+        if local_file:
+            image = read_image_from_filename(image_uri, imread_flag)
+        else:
+            image = read_image_from_url(image_uri, imread_flag)
+        assert image is not None
+    except Exception as e:
+        raise ValueError(f"Could not load image at {image_uri}: {e}")
+    return image
+
+
+def rescale_image(image: np.ndarray) -> np.ndarray:
+    """Rescale image from [0, 1] to [0, 255]."""
+    if image.max() <= 1.0:
+        image = 255 * (image - image.min()) / (image.max() - image.min())
+    return image
+
+
+def write_image(image: np.ndarray, filename: Union[Path, str]) -> None:
+    """Write image to file."""
+    image = rescale_image(image)
+    cv2.imwrite(str(filename), image)