diff --git a/imgaug/imgaug.py b/imgaug/imgaug.py
index 924608c22..68149feac 100644
--- a/imgaug/imgaug.py
+++ b/imgaug/imgaug.py
@@ -36,9 +36,9 @@
 # to check if a dtype instance is among these dtypes, use e.g.
 # `dtype.type in  NP_FLOAT_TYPES` do not just use `dtype in NP_FLOAT_TYPES` as
 # that would fail
-NP_FLOAT_TYPES = set(np.sctypes["float"])
-NP_INT_TYPES = set(np.sctypes["int"])
-NP_UINT_TYPES = set(np.sctypes["uint"])
+NP_FLOAT_TYPES = set([np.float16, np.float32, np.float64, np.float128],)
+NP_INT_TYPES = set([np.int8, np.int16, np.int32, np.int64])
+NP_UINT_TYPES = set([np.uint8, np.uint16, np.uint32, np.uint64],)
 
 IMSHOW_BACKEND_DEFAULT = "matplotlib"