Upload bubble_detect.py

utils/bubble_detect.py

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+import cv2
+import numpy as np
+from shapely.geometry import Polygon
+
+def detect_speech_bubbles(img_pil):
+    img = cv2.cvtColor(np.array(img_pil), cv2.COLOR_RGB2BGR)
+    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
+
+    # Adaptive threshold handles dark scenes + uneven lighting
+    th = cv2.adaptiveThreshold(
+        gray, 255,
+        cv2.ADAPTIVE_THRESH_GAUSSIAN_C,
+        cv2.THRESH_BINARY,
+        35, 10
+    )
+
+    inv = 255 - th   # bubbles become white
+
+    # Close small gaps in bubble borders
+    kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE, (7, 7))
+    cleaned = cv2.morphologyEx(inv, cv2.MORPH_CLOSE, kernel, iterations=2)
+
+    contours, _ = cv2.findContours(cleaned, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
+
+    bubbles = []
+
+    for cnt in contours:
+        area = cv2.contourArea(cnt)
+        if area < 500:
+            continue
+
+        approx = cv2.approxPolyDP(cnt, 0.01 * cv2.arcLength(cnt, True), True)
+
+        poly = [(int(p[0][0]), int(p[0][1])) for p in approx]
+
+        # verify shape is bubble-like (optional)
+        bubbles.append(poly)
+
+    return bubbles