From d5626bbba9cda975901ef0f8ff6111f3c8de4755 Mon Sep 17 00:00:00 2001
From: timonpalm <timon.palm@gmx.de>
Date: Mon, 11 Nov 2024 23:17:14 +0100
Subject: [PATCH] empty segmentation fix

---
 sahi/postprocess/utils.py | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/sahi/postprocess/utils.py b/sahi/postprocess/utils.py
index 193cb684..6fcae37c 100644
--- a/sahi/postprocess/utils.py
+++ b/sahi/postprocess/utils.py
@@ -167,7 +167,14 @@ def get_merged_mask(pred1: ObjectPrediction, pred2: ObjectPrediction) -> Mask:
     # buffer(0) is a quickhack to fix invalid polygons most of the time
     poly1 = get_shapely_multipolygon(mask1.segmentation).buffer(0)
     poly2 = get_shapely_multipolygon(mask2.segmentation).buffer(0)
-    union_poly = poly1.union(poly2)
+
+    if poly1.is_empty:
+        union_poly = poly2
+    elif poly2.is_empty:
+        union_poly = poly1
+    else:
+        union_poly = poly1.union(poly2)
+
     if not hasattr(union_poly, "geoms"):
         union_poly = MultiPolygon([union_poly])
     else: