use existing functionality for fix

skimage/filter/_tv_denoise.py

@@ -1,4 +1,5 @@
 import numpy as np
+from skimage.util import dtype
 
 
 def _tv_denoise_3d(im, weight=100, eps=2.e-4, n_iter_max=200):
@@ -169,30 +170,6 @@ def _tv_denoise_2d(im, weight=50, eps=2.e-4, n_iter_max=200):
                 E_previous = E
         i += 1
     return out
-
-def _renormalize_image(image, data_type):
-    """
-    inplace renormalize image date to obey the float range [0.0:1.0]
-
-    Parameters
-    ----------
-    immage: ndarray
-        input data to be renormalized
-
-    data_type: type,
-        image data type before running tv_denoise
-
-    Notes
-    -------
-    the minimum and maximum values of the image data type define the range
-    which is mapped to the interval [0.0:1.0] 
-
-    """
-    type_info = np.iinfo(data_type)
-    start = type_info.min
-    width = type_info.max - type_info.min
-    np.subtract(image, start, image)
-    np.divide(image, width, image)  
     
 def tv_denoise(im, weight=50, eps=2.e-4, keep_type=False, n_iter_max=200):
     """
@@ -281,5 +258,5 @@ def tv_denoise(im, weight=50, eps=2.e-4, keep_type=False, n_iter_max=200):
         return out.astype(im_type)
     else:
         if not im_type.kind == 'f':
-            _renormalize_image(out, im_type)
+            out = dtype.convert(out.astype(im_type), np.float)
         return out