add crop and pad util

docs/en/reference/utils/__init__.md

@@ -177,4 +177,8 @@ keywords: Ultralytics, utils, TQDM, Python, ML, Machine Learning utilities, YOLO
 
 ## ::: ultralytics.utils.vscode_msg
 
+<br><br><hr><br>
+
+## ::: ultralytics.utils.crop_and_pad
+
 <br><br>

ultralytics/utils/__init__.py

@@ -1258,6 +1258,29 @@ def vscode_msg(ext="ultralytics.ultralytics-snippets") -> str:
     return "" if installed else f"{colorstr('VS Code:')} view Ultralytics VS Code Extension ⚡ at {url}"
 
 
+def crop_and_pad(frame, box, margin_percent):
+    """Crop box with margin and take square crop from frame."""
+    x1, y1, x2, y2 = map(int, box)
+    w, h = x2 - x1, y2 - y1
+
+    # Add margin
+    margin_x, margin_y = int(w * margin_percent / 100), int(h * margin_percent / 100)
+    x1, y1 = max(0, x1 - margin_x), max(0, y1 - margin_y)
+    x2, y2 = min(frame.shape[1], x2 + margin_x), min(frame.shape[0], y2 + margin_y)
+
+    # Take square crop from frame
+    size = max(y2 - y1, x2 - x1)
+    center_y, center_x = (y1 + y2) // 2, (x1 + x2) // 2
+    half_size = size // 2
+    square_crop = frame[
+        max(0, center_y - half_size) : min(frame.shape[0], center_y + half_size),
+        max(0, center_x - half_size) : min(frame.shape[1], center_x + half_size),
+    ]
+
+    return cv2.resize(square_crop, (224, 224), interpolation=cv2.INTER_LINEAR)
+
+
+
 # Run below code on utils init ------------------------------------------------------------------------------------
 
 # Check first-install steps