feat: exposure detection (over/underexposed)

analyzer.py

@@ -1,5 +1,6 @@
 import cv2
 import numpy as np
+from PIL import Image
 
 
 def is_blurry(path: str, threshold: float = 100.0) -> bool:
@@ -9,3 +10,20 @@ def is_blurry(path: str, threshold: float = 100.0) -> bool:
         return False
     variance = cv2.Laplacian(img, cv2.CV_64F).var()
     return bool(variance < threshold)
+
+
+def _mean_brightness(path: str) -> float:
+    """Durchschnittliche Helligkeit eines Bildes (0-255)."""
+    img = Image.open(path).convert("L")
+    arr = np.array(img, dtype=np.float32)
+    return float(arr.mean())
+
+
+def is_overexposed(path: str, threshold: float = 240.0) -> bool:
+    """Gibt True zurueck, wenn das Bild ueberbelichtet ist."""
+    return _mean_brightness(path) > threshold
+
+
+def is_underexposed(path: str, threshold: float = 30.0) -> bool:
+    """Gibt True zurueck, wenn das Bild unterbelichtet ist."""
+    return _mean_brightness(path) < threshold