dev(narugo): add laplacian score

imgutils/metrics/__init__.py

@@ -5,5 +5,6 @@
 from .aesthetic import *
 from .ccip import *
 from .dbaesthetic import *
+from .laplacian import *
 from .lpips import *
 from .psnr_ import *

imgutils/metrics/laplacian.py

@@ -0,0 +1,35 @@
+import cv2
+import numpy as np
+
+from ..data import load_image, ImageTyping
+
+__all__ = [
+    'laplacian_score'
+]
+
+
+def _variance_of_laplacian(d_image: np.ndarray):
+    """
+    Calculate the variance of Laplacian for a given image.
+
+    :param d_image: The input image as a numpy array.
+    :type d_image: np.ndarray
+    :return: The variance of Laplacian.
+    :rtype: float
+    """
+    return cv2.Laplacian(d_image, cv2.CV_64F).var()
+
+
+def laplacian_score(image: ImageTyping) -> float:
+    """
+    Calculate the Laplacian score for the given image.
+
+    The Laplacian score is a measure of image bluriness.
+
+    :param image: The input image.
+    :type image: ImageTyping
+    :return: The Laplacian score.
+    :rtype: float
+    """
+    v = np.array(load_image(image, force_background='white', mode='L'))
+    return _variance_of_laplacian(v).item()