diff --git a/PythonAPI/pycocotools/coco.py b/PythonAPI/pycocotools/coco.py
index 58bc7eaa..b4abba81 100644
--- a/PythonAPI/pycocotools/coco.py
+++ b/PythonAPI/pycocotools/coco.py
@@ -198,6 +198,29 @@ def getImgIds(self, imgIds=[], catIds=[]):
                     ids &= set(self.catToImgs[catId])
         return list(ids)
 
+    #get IDs of images which contain one or more of each category
+    def getImgIdsUnion(self, imgIds=[], catIds=[]):
+        '''
+        Get img ids that satisfy given filter conditions.
+        :param imgIds (int array) : get imgs for given ids
+        :param catIds (int array) : get imgs with all given cats
+        :return: ids (int array)  : integer array of img ids
+        '''
+        imgIds = imgIds if _isArrayLike(imgIds) else [imgIds]
+        catIds = catIds if _isArrayLike(catIds) else [catIds]
+
+        if len(imgIds) == len(catIds) == 0:
+            ids = self.imgs.keys()
+        else:
+            ids = set(imgIds)
+            for i, catId in enumerate(catIds):
+                if i == 0 and len(ids) == 0:
+                    ids = set(self.catToImgs[catId])
+                else:
+                    ids |= set(self.catToImgs[catId])
+        return list(ids)
+
+
     def loadAnns(self, ids=[]):
         """
         Load anns with the specified ids.