Parasitemia/Parasitemia/MatchingEllipses.fs

   1 module MatchingEllipses
   2
   3 open System
   4 open System.Linq
   5 open System.Collections
   6 open System.Collections.Generic
   7
   8 open Types
   9 open Utils
  10
  11
  12 let matchingScoreThreshold1 = 0.6
  13 let matchingScoreThreshold2 = 1.0
  14
  15 type private EllipseScoreFlaggedKd (matchingScore: float, e: Ellipse) =
  16     let mutable matchingScore = matchingScore
  17
  18     member this.Ellipse = e
  19
  20     member this.MatchingScore = matchingScore
  21     member this.AddMatchingScore(score: float) =
  22         matchingScore <- matchingScore + score
  23
  24     member val Processed = false with get, set
  25     member val Removed = false with get, set
  26
  27     interface KdTree.I2DCoords with
  28         member this.X = this.Ellipse.Cx
  29         member this.Y = this.Ellipse.Cy
  30
  31
  32 type MatchingEllipses (radiusMin: float) =
  33     let ellipses = List<EllipseScoreFlaggedKd>()
  34
  35     member this.Add (e: Ellipse) =
  36         ellipses.Add(EllipseScoreFlaggedKd(0.0, e))
  37
  38     member this.Ellipses : Ellipse list =
  39         if ellipses.Count = 0
  40         then
  41             []
  42         else
  43             // 1) Create a kd-tree from the ellipses list.
  44             let tree = KdTree.Tree.BuildTree (List.ofSeq ellipses)
  45
  46             // 2) Compute the matching score of each ellipses.
  47             let windowSize = radiusMin
  48             for e in ellipses do
  49                 e.Processed <- true
  50                 let areaE = e.Ellipse.Area
  51                 let window = { KdTree.minX = e.Ellipse.Cx - windowSize / 2.0
  52                                KdTree.maxX = e.Ellipse.Cx + windowSize / 2.0
  53                                KdTree.minY = e.Ellipse.Cy - windowSize / 2.0
  54                                KdTree.maxY = e.Ellipse.Cy + windowSize / 2.0 }
  55                 for other in tree.Search window do
  56                     if not other.Processed
  57                     then
  58                         let areaOther = other.Ellipse.Area
  59                         match EEOver.EEOverlapArea e.Ellipse other.Ellipse with
  60                         | Some (commonArea, _, _) ->
  61                             let matchingScore = 2.0 * commonArea / (areaE + areaOther)
  62                             if matchingScore >= matchingScoreThreshold1
  63                             then
  64                                 other.AddMatchingScore(matchingScore)
  65                                 e.AddMatchingScore(matchingScore)
  66                         | _ -> ()
  67
  68             // 3) Sort ellipses by their score.
  69             ellipses.Sort(fun e1 e2 -> e2.MatchingScore.CompareTo(e1.MatchingScore))
  70
  71             // 4) Remove ellipses wich have a low score.
  72             let i = ellipses.BinarySearch(EllipseScoreFlaggedKd(matchingScoreThreshold2, Ellipse(0.0, 0.0, 0.0, 0.0, 0.0)),
  73                                           { new IComparer<EllipseScoreFlaggedKd> with
  74                                                 member this.Compare(e1, e2) = e2.MatchingScore.CompareTo(e1.MatchingScore) }) |> abs
  75             let nbToRemove = ellipses.Count - i
  76             if nbToRemove > 0
  77             then
  78                 for j in i .. nbToRemove - 1 do
  79                     ellipses.[j].Removed <- true
  80                 ellipses.RemoveRange(i, nbToRemove)
  81
  82             // 5) Remove ellipses whose center is into an ellipse with a better score
  83             for e in ellipses do
  84                 if not e.Removed
  85                 then
  86                     let window = { KdTree.minX = e.Ellipse.Cx - e.Ellipse.A
  87                                    KdTree.maxX = e.Ellipse.Cx + e.Ellipse.A
  88                                    KdTree.minY = e.Ellipse.Cy - e.Ellipse.A
  89                                    KdTree.maxY = e.Ellipse.Cy + e.Ellipse.A }
  90                     for other in tree.Search window do
  91                         if not other.Removed && other.MatchingScore < e.MatchingScore
  92                         then
  93                             if e.Ellipse.Contains other.Ellipse.Cx other.Ellipse.Cy
  94                             then
  95                                 other.Removed <- true
  96             ellipses.RemoveAll(fun e -> e.Removed) |> ignore
  97
  98             List.ofSeq ellipses |> List.map (fun e -> e.Ellipse)
  99
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