Parasitemia/Parasitemia/KMeans.fs

   1 module KMeans
   2
   3 open System.Collections.Generic
   4 open System.Drawing
   5
   6 open Emgu.CV
   7 open Emgu.CV.Structure
   8
   9 type Result = {
  10     fg: Image<Gray, byte>
  11     mean_bg: float
  12     mean_fg: float
  13     d_fg: Image<Gray, float32> } // Euclidean distances of the foreground to mean_fg.
  14
  15 let kmeans (img: Image<Gray, float32>) (fgFactor: float) : Result =
  16     let nbIteration = 3
  17     let w = img.Width
  18     let h = img.Height
  19
  20     let min = ref [| 0.0 |]
  21     let minLocation = ref <| [| Point() |]
  22     let max = ref [| 0.0 |]
  23     let maxLocation = ref <| [| Point() |]
  24     img.MinMax(min, max, minLocation, maxLocation)
  25
  26     let mutable mean_bg = (!max).[0] - ((!max).[0] - (!min).[0]) / 4.0
  27     let mutable mean_fg = (!min).[0] + ((!max).[0] - (!min).[0]) / 4.0
  28     use mutable d_bg = new Image<Gray, float32>(img.Size)
  29     let mutable d_fg = new Image<Gray, float32>(img.Size)
  30     let mutable fg = new Image<Gray, byte>(img.Size)
  31
  32     for i in 1 .. nbIteration do
  33         d_bg <- img.AbsDiff(Gray(mean_bg))
  34         d_fg <- img.AbsDiff(Gray(mean_fg))
  35
  36         CvInvoke.Compare(d_fg, d_bg, fg, CvEnum.CmpType.LessThan)
  37
  38         let mutable bg_total = 0.0
  39         let mutable bg_nb = 0
  40
  41         let mutable fg_total = 0.0
  42         let mutable fg_nb = 0
  43
  44         for i in 0 .. h - 1 do
  45             for j in 0 .. w - 1 do
  46                 if fg.Data.[i, j, 0] > 0uy
  47                 then
  48                     fg_total <- fg_total + float img.Data.[i, j, 0]
  49                     fg_nb <- fg_nb + 1
  50                 else
  51                     bg_total <- bg_total + float img.Data.[i, j, 0]
  52                     bg_nb <- bg_nb + 1
  53
  54         mean_bg <- bg_total / float bg_nb
  55         mean_fg <- fg_total / float fg_nb
  56
  57     { fg = fg; mean_bg = mean_bg; mean_fg = mean_fg; d_fg = d_fg }