let mutable mean_fg = minf + (maxf - minf) / 4.f
use mutable d_bg : Image<Gray, float32> = null
let mutable d_fg : Image<Gray, float32> = null
let mutable mean_fg = minf + (maxf - minf) / 4.f
use mutable d_bg : Image<Gray, float32> = null
let mutable d_fg : Image<Gray, float32> = null