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"""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.exists(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)
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