diff --git a/skimage/feature/orb_cy.pyx b/skimage/feature/orb_cy.pyx
index b1af3af2..82c6e6ad 100644
--- a/skimage/feature/orb_cy.pyx
+++ b/skimage/feature/orb_cy.pyx
@@ -5,6 +5,7 @@
 
 cimport numpy as cnp
 import numpy as np
+import os
 
 from libc.math cimport sin, cos, round