diff --git a/skimage/filter/__init__.py b/skimage/filter/__init__.py
index 04c972cc..bdbbb531 100644
--- a/skimage/filter/__init__.py
+++ b/skimage/filter/__init__.py
@@ -1,7 +1,7 @@
 from .lpi_filter import *
 from .ctmf import median_filter
-from .canny import canny
+from ._canny import canny
 from .edges import sobel, hsobel, vsobel, hprewitt, vprewitt, prewitt
-from .tv_denoise import tv_denoise
-from .rank_order import rank_order
+from ._tv_denoise import tv_denoise
+from ._rank_order import rank_order
 from .thresholding import threshold_otsu, threshold_adaptive
diff --git a/skimage/filter/canny.py b/skimage/filter/_canny.py
similarity index 100%
rename from skimage/filter/canny.py
rename to skimage/filter/_canny.py
diff --git a/skimage/filter/rank_order.py b/skimage/filter/_rank_order.py
similarity index 100%
rename from skimage/filter/rank_order.py
rename to skimage/filter/_rank_order.py
diff --git a/skimage/filter/tv_denoise.py b/skimage/filter/_tv_denoise.py
similarity index 100%
rename from skimage/filter/tv_denoise.py
rename to skimage/filter/_tv_denoise.py