diff --git a/skimage/filter/rank/README.rst b/skimage/filter/rank/README.rst
index 29a68edb..cdf8205c 100644
--- a/skimage/filter/rank/README.rst
+++ b/skimage/filter/rank/README.rst
@@ -8,25 +8,25 @@ To do
 General remarks
 ---------------
 
-Basically these filters compute local histogram for each pixel. Histogram is
-build using a moving window in order to limit redundant computation. The path
+Basically these filters compute local histogram for each pixel. A histogram is
+built using a moving window in order to limit redundant computation. The path
 followed by the moving window is given hereunder
 
  ...-----------------------\
 /--------------------------/
 \-------------------------- ...
 
-A comparison is proposed with cmorph.dilate algorithm to show how computation
-costs evolve with respect to image size or structuring element size. This
-implementation gives better results for large structuring elements.
+We compare cmorph.dilate to this histogram based method to show how
+computational costs increase with respect to image size or structuring element
+size. This implementation gives better results for large structuring elements.
 
-A local histogram is update at each pixel by introducing pixel entering the
-structuring element border and by removing those leaving it. The histogram size
-is 8bit (256 bins) for 8 bit images and 2 to 12 bit (up to 4096 bins) for 16bit
-image depending on the image maximum value. Image with pixels higher than 4095
-raise a ValueError.
+The local histogram is updated at each pixel as the structuring element window
+moves by, i.e. only those pixels entering and leaving the structuring element
+update the local histogram. The histogram size is 8-bit (256 bins) for 8-bit
+images and 2 to 12-bit (up to 4096 bins) for 16-bit images depending on the
+maximum value of the image. Pixel values higher than 4095 raise a ValueError.
 
 The filter is applied up to the image border, the neighboorhood used is adjusted
 accordingly. The user may provide a mask image (same size as input image) where
-non zero value are the part of the image participating the the histogram
-computation. By default all the image is filtered.
+non zero values are the part of the image participating in the histogram
+computation. By default the entire image is filtered.