From 487f16562257778b4aced56de126f7fddffc9159 Mon Sep 17 00:00:00 2001
From: Andreas Mueller <amueller@ais.uni-bonn.de>
Date: Thu, 29 Sep 2011 13:30:53 +0200
Subject: [PATCH 1/2] slightly faster image conversion by creating less
 temporaries.

---
 scikits/image/util/dtype.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/scikits/image/util/dtype.py b/scikits/image/util/dtype.py
index b859f044..b1b5600d 100644
--- a/scikits/image/util/dtype.py
+++ b/scikits/image/util/dtype.py
@@ -75,7 +75,10 @@ def _convert(image, dtype, prec_loss):
 
     # Do scaling/shifting calculations in floating point
     image = image.astype(np.float64)
-    out = round_fn((image - imin) * scale + shift).astype(dtype)
+    out = image - imin
+    out *= scale
+    out += shift
+    out = round_fn(out).astype(dtype)
 
     return out
 

From d7761bae546355e3b84d8ea48f3acd86c5efb743 Mon Sep 17 00:00:00 2001
From: Andreas Mueller <amueller@ais.uni-bonn.de>
Date: Thu, 29 Sep 2011 13:31:07 +0200
Subject: [PATCH 2/2] pep8 whitespace

---
 scikits/image/util/dtype.py | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/scikits/image/util/dtype.py b/scikits/image/util/dtype.py
index b1b5600d..7a03fd5a 100644
--- a/scikits/image/util/dtype.py
+++ b/scikits/image/util/dtype.py
@@ -15,6 +15,7 @@ dtype_range = {np.uint8: (0, 255),
 
 integer_types = (np.uint8, np.uint16, np.int8, np.int16)
 
+
 def _convert(image, dtype, prec_loss):
     """
     Convert an image to the requested data-type.
@@ -38,7 +39,7 @@ def _convert(image, dtype, prec_loss):
 
     if dtype_in == dtype:
         return image
-    
+
     if dtype_in in prec_loss:
         log.warn('Possible precision loss, converting from '
                  '%s to %s' % (np.dtype(dtype_in), np.dtype(dtype)))
@@ -82,6 +83,7 @@ def _convert(image, dtype, prec_loss):
 
     return out
 
+
 def img_as_float(image):
     """Convert an image to double-precision floating point format.
 
@@ -104,6 +106,7 @@ def img_as_float(image):
     prec_loss = ()
     return _convert(image, np.float64, prec_loss)
 
+
 def img_as_uint(image):
     """Convert an image to 16-bit unsigned integer format.
 
@@ -126,6 +129,7 @@ def img_as_uint(image):
     prec_loss = (np.float32, np.float64)
     return _convert(image, np.uint16, prec_loss)
 
+
 def img_as_int(image):
     """Convert an image to 16-bit signed integer format.
 
@@ -148,6 +152,7 @@ def img_as_int(image):
     prec_loss = (np.float32, np.float64, np.uint16)
     return _convert(image, np.int16, prec_loss)
 
+
 def img_as_ubyte(image):
     """Convert an image to 8-bit unsigned integer format.