diff --git a/annolid/segmentation/SAM/edge_sam_bg.py b/annolid/segmentation/SAM/edge_sam_bg.py
index 1f8830a..703bdfa 100644
--- a/annolid/segmentation/SAM/edge_sam_bg.py
+++ b/annolid/segmentation/SAM/edge_sam_bg.py
@@ -209,6 +209,9 @@ def process_video_with_cutite(self, frames_to_propagate=100,
         frame_number = int(
             Path(self.most_recent_file).stem.split('_')[-1])
         shapes = self.load_shapes(self.most_recent_file)
+        shapes = [shape for shape in shapes if len(shape["points"]) >= 3]
+        if len(shapes) < 1:
+            return f"No valid polygon found in this frame; requires a minimum of 3 points #{frame_number} "
         for shape in sorted(shapes, key=lambda x: x["label"]):
             label_name = shape["label"]
             if label_name in label_name_to_value: