stdiff

Name

stdiff - local statistical differencing

Syntax

stdiff <inimage> <outimage> <deltax> <deltay> <alpha> <beta> <m0> <s0>

Description

Local Pixel Value Mapping.

 r(x,y) = u(x,y) + s(x,y)
 u(x,y) = alpha * m0 + (1-alpha) * bm(x,y)
 s(x,y) = (b(x,y)-bm(x,y)) * (beta*s0 / (s0+bs(x,y)))

 r(x,y)  = output image
 u(x,y)  = mean component
 s(x,y)  = st. dev component
 m0      = The mean to force locally
 alpha   = fraction m0 <--> local mean
 b(b,y)  = pixel value in (x,y)
 bm(x,y) = local mean
 bs(x,y) = local st. dev
 s0      = new st. dev
 beta    = parameter to control s0 <--> local st.dev

deltax is local area width, deltay is local area height.

Se also

Wayne Niblack: An introduction to Digital Image Processing

Restrictions

inimage must have bands with pixel type unsigned byte.

Author

Otto Milvang

Id

$Id: stdiff.c,v 1.31 1997/01/30 18:27:02 svein Exp $