Implement green screen matting pipeline

bgfilter/deps.py

@@ -0,0 +1,16 @@
+from __future__ import annotations
+
+
+def require_module(module_name: str, install_hint: str):
+    try:
+        return __import__(module_name)
+    except ModuleNotFoundError as exc:
+        if exc.name == module_name:
+            raise RuntimeError(
+                f"Missing dependency '{module_name}'. Install it with: {install_hint}"
+            ) from exc
+        raise
+
+
+def require_cv2():
+    return require_module("cv2", "pip install opencv-python")