--- /dev/null
+module ParasitemiaCore.KMeans
+
+open System.Collections.Generic
+open System.Drawing
+
+open Emgu.CV
+open Emgu.CV.Structure
+
+type Result = {
+ fg: Image<Gray, byte>
+ mean_bg: float32
+ mean_fg: float32
+ d_fg: Image<Gray, float32> } // Euclidean distances of the foreground to mean_fg.
+
+let kmeans (img: Image<Gray, float32>) : Result =
+ let nbIteration = 4
+ let w = img.Width
+ let h = img.Height
+
+ let min = ref [| 0.0 |]
+ let minLocation = ref <| [| Point() |]
+ let max = ref [| 0.0 |]
+ let maxLocation = ref <| [| Point() |]
+ img.MinMax(min, max, minLocation, maxLocation)
+
+ let minf = float32 (!min).[0]
+ let maxf = float32 (!max).[0]
+
+ let mutable mean_bg = maxf - (maxf - minf) / 4.f
+ 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 fg = new Image<Gray, byte>(img.Size)
+
+ let imgData = img.Data
+ let fgData = fg.Data
+
+ for i in 1 .. nbIteration do
+ match d_bg with
+ | null -> ()
+ | _ ->
+ d_bg.Dispose()
+ d_fg.Dispose()
+
+ // EmGu doesn't import the in-place version of 'AbsDiff' so we have to create two images for each iteration.
+ d_bg <- img.AbsDiff(Gray(float mean_bg))
+ d_fg <- img.AbsDiff(Gray(float mean_fg))
+
+ CvInvoke.Compare(d_fg, d_bg, fg, CvEnum.CmpType.LessThan)
+
+ let mutable bg_total = 0.f
+ let mutable bg_nb = 0
+
+ let mutable fg_total = 0.f
+ let mutable fg_nb = 0
+
+ for i in 0 .. h - 1 do
+ for j in 0 .. w - 1 do
+ if fgData.[i, j, 0] > 0uy
+ then
+ fg_total <- fg_total + imgData.[i, j, 0]
+ fg_nb <- fg_nb + 1
+ else
+ bg_total <- bg_total + imgData.[i, j, 0]
+ bg_nb <- bg_nb + 1
+
+ mean_bg <- bg_total / float32 bg_nb
+ mean_fg <- fg_total / float32 fg_nb
+
+ { fg = fg; mean_bg = mean_bg; mean_fg = mean_fg; d_fg = d_fg }
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