diff --git a/skimage/measure/_regionprops.py b/skimage/measure/_regionprops.py
index 0156a6bc..e89d33e0 100644
--- a/skimage/measure/_regionprops.py
+++ b/skimage/measure/_regionprops.py
@@ -13,8 +13,8 @@ __all__ = ['regionprops']
 
 STREL_4 = np.array([[0, 1, 0],
                     [1, 1, 1],
-                    [0, 1, 0]])
-STREL_8 = np.ones((3, 3), 'int8')
+                    [0, 1, 0]], dtype=np.uint8)
+STREL_8 = np.ones((3, 3), dtype=np.uint8)
 PROPS = {
     'Area': 'area',
     'BoundingBox': 'bbox',
@@ -498,14 +498,14 @@ def perimeter(image, neighbourhood=4):
     Parameters
     ----------
     image : array
-        binary image
+        Binary image.
     neighbourhood : 4 or 8, optional
-        neighbourhood connectivity for border pixel determination, default 4
+        Neighborhood connectivity for border pixel determination.
 
     Returns
     -------
     perimeter : float
-        total perimeter of all objects in binary image
+        Total perimeter of all objects in binary image.
 
     References
     ----------
@@ -521,7 +521,7 @@ def perimeter(image, neighbourhood=4):
     eroded_image = ndimage.binary_erosion(image, strel, border_value=0)
     border_image = image - eroded_image
 
-    perimeter_weights = np.zeros(50, float)
+    perimeter_weights = np.zeros(50, dtype=np.float32)
     perimeter_weights[[5, 7, 15, 17, 25, 27]] = 1
     perimeter_weights[[21, 33]] = sqrt(2)
     perimeter_weights[[13, 23]] = (1 + sqrt(2)) / 2