diff --git a/tools/data/dota/split/img_split.py b/tools/data/dota/split/img_split.py
index 63279d3c4..a873b2458 100644
--- a/tools/data/dota/split/img_split.py
+++ b/tools/data/dota/split/img_split.py
@@ -199,7 +199,7 @@ def poly2hbb(polys):
     return np.concatenate([lt_point, rb_point], axis=-1)
 
 
-def bbox_overlaps_iof(bboxes1, bboxes2, eps=1e-6):
+def bbox_overlaps_iof(bboxes1, bboxes2, eps=1e-3):
     """Compute bbox overlaps (iof).
 
     Args:
@@ -229,8 +229,12 @@ def bbox_overlaps_iof(bboxes1, bboxes2, eps=1e-6):
     if shgeo is None:
         raise ImportError('Please run "pip install shapely" '
                           'to install shapely first.')
-    sg_polys1 = [shgeo.Polygon(p) for p in bboxes1.reshape(rows, -1, 2)]
-    sg_polys2 = [shgeo.Polygon(p) for p in polys2.reshape(cols, -1, 2)]
+    sg_polys1 = [
+        shgeo.Polygon(p).buffer(eps) for p in bboxes1.reshape(rows, -1, 2)
+    ]
+    sg_polys2 = [
+        shgeo.Polygon(p).buffer(eps) for p in polys2.reshape(cols, -1, 2)
+    ]
     overlaps = np.zeros(h_overlaps.shape)
     for p in zip(*np.nonzero(h_overlaps)):
         overlaps[p] = sg_polys1[p[0]].intersection(sg_polys2[p[-1]]).area