diff --git a/core/misc/voxel2vector.h b/core/misc/voxel2vector.h
index d7798a3371..1b61503784 100644
--- a/core/misc/voxel2vector.h
+++ b/core/misc/voxel2vector.h
@@ -72,8 +72,8 @@ class Voxel2Vector {
   Image<index_t> forward;
   std::vector<std::vector<index_t>> reverse;
 
-  vector<index_t> pos() const {
-    vector<index_t> result;
+  std::vector<index_t> pos() const {
+    std::vector<index_t> result;
     for (size_t index = 0; index != forward.ndim(); ++index)
       result.push_back(forward.index(index));
     return result;