Parasitemia/Parasitemia/Granulometry.fs

   1 module Granulometry
   2
   3 open System
   4 open System.Drawing
   5
   6 open Emgu.CV
   7 open Emgu.CV.Structure
   8
   9 open Utils
  10
  11 // 'range': a minimum and maximum radius.
  12 // 'scale': <= 1.0, to speed up the process.
  13 let findRadius (img: Image<Gray, 'TDepth>) (range: int * int) (scale: float) : int =
  14     use scaledImg = if scale = 1.0 then img else img.Resize(scale, CvEnum.Inter.Area)
  15
  16     let r1, r2 = range
  17     let r1', r2' = roundInt (float r1 * scale), roundInt (float r2 * scale)
  18
  19     let patternSpectrum = Array.zeroCreate (r2' - r1')
  20     let intensityImg = scaledImg.GetSum().Intensity
  21
  22     let mutable previous_n = Double.NaN
  23     for r in r1' .. r2' do
  24         let se = CvInvoke.GetStructuringElement(CvEnum.ElementShape.Ellipse, Size(2 * r, 2 * r), Point(-1, -1))
  25         use closed = scaledImg.MorphologyEx(CvEnum.MorphOp.Close, se, Point(-1, -1), 1, CvEnum.BorderType.Replicate, MCvScalar(0.0))
  26
  27         let n = closed.GetSum().Intensity
  28
  29         if not (Double.IsNaN previous_n)
  30         then
  31             patternSpectrum.[r - r1' - 1] <- abs (n - previous_n)
  32         previous_n <- n
  33
  34     let max, _ = patternSpectrum |> Array.indexed |> Array.fold (fun (iMax, sMax) (i, s) -> if s > sMax then (i, s) else (iMax, sMax)) (0, Double.MinValue)
  35
  36     float (max + r1') / scale |> roundInt
  37
  38