Extract the type and shape checks into a common function.

scikits/image/color/colorconv.py

@@ -13,6 +13,18 @@ __docformat__ = "restructuredtext en"
 
 import numpy as np
 
+
+def _prepare_colorarray(arr, dtype="float32"):
+    """Check the shape of the array, and give it the requested type"""
+    if type(arr) != np.ndarray:
+        raise TypeError, "the input array must be a numpy.ndarray"
+
+    if arr.ndim != 3 or arr.shape[2] != 3:
+        msg = "the input array must be have a shape == (.,.,3))"
+        raise ValueError, msg
+
+    return arr.astype(dtype)
+
 def rgb2hsv(rgb):
     """RGB to HSV color space conversion.
 
@@ -49,15 +61,7 @@ def rgb2hsv(rgb):
     >>> lena = imread(os.path.join(data_dir, 'lena.png'))
     >>> lena_hsv = color.rgb2hsv(lena)
     """
-
-    if type(rgb) != np.ndarray:
-        raise TypeError, "the input array 'rgb' must be a numpy.ndarray"
-
-    if rgb.ndim != 3 or rgb.shape[2] != 3:
-        msg = "the input array 'rgb' must be have a shape == (.,.,3))"
-        raise ValueError, msg
-
-    arr = rgb.astype("float32")
+    arr = _prepare_colorarray(rgb)
     out = np.empty_like(arr)
 
     # -- V channel
@@ -130,15 +134,7 @@ def hsv2rgb(hsv):
     >>> lena_hsv = rgb2hsv(lena)
     >>> lena_rgb = hsv2rgb(lena_hsv)
     """
-
-    if type(hsv) != np.ndarray:
-        raise TypeError, "the input array 'hsv' must be a numpy.ndarray"
-
-    if hsv.ndim != 3 or hsv.shape[2] != 3:
-        msg = "the input array 'hsv' must be have a shape == (.,.,3))"
-        raise ValueError, msg
-
-    arr = hsv.astype("float32")
+    arr = _prepare_colorarray(hsv)
 
     hi = np.floor(arr[:,:,0] * 6)
     f = arr[:,:,0] * 6 - hi