title: Renderscript Intrinsics documentation
body: <p>I use the Renderscript ScriptIntrinsicBlur, which which works great and saves my app a lot of calculation time. However, I was looking for a kind of a user guide and documentation of these very useful Renderscript Intrinsic functions but found almost nothing, except some high level technical info on the developer site. For example:</p>
  
  <blockquote>
    <p>how is the blur radius of ScriptIntrinsicBlur defined? I assume it must some cut-off of the gaussian Sigma in relation to the kernel size (e.g. 99%), but I didn't find anything on that.
    also I would be interested in the histogram function, e.g. in order to apply them for histogram-matching of two Pictures. But I found little on that. 
    how exactly are the types U8_4, U8_3, U8_2, U8 defined? And what type would be most efficient for Gray-Value Pictures?</p>
  </blockquote>
  
  <p>Thanks for any Feedback.</p>