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 // Do not take in account matching score below this when two ellipses are matched.
  13 [<Literal>]
  14 let matchingScoreThreshold1 = 0.6f
  15
  16 [<Literal>]
  17 let scaleOverlapTest = 0.8f
  18
  19 type private EllipseScoreFlaggedKd (matchingScore: float32, e: Ellipse) =
  20     let mutable matchingScore = matchingScore
  21
  22     member this.Ellipse = e
  23
  24     member this.MatchingScore = matchingScore
  25
  26     member this.AddMatchingScore(score: float32) =
  27         matchingScore <- matchingScore + score
  28
  29     member val Processed = false with get, set
  30     member val Removed = false with get, set
  31
  32     interface KdTree.I2DCoords with
  33         member this.X = this.Ellipse.Cx
  34         member this.Y = this.Ellipse.Cy
  35
  36
  37 type MatchingEllipses (radiusMin: float32) =
  38     let ellipses = List<EllipseScoreFlaggedKd>()
  39
  40     // All ellipses with a score below this are removed.
  41     let matchingScoreThreshold2 = 20.f * radiusMin
  42
  43     member this.Add (e: Ellipse) =
  44         ellipses.Add(EllipseScoreFlaggedKd(0.f, e))
  45
  46     member this.Ellipses : Ellipse list =
  47         List.ofSeq ellipses |> List.map (fun e -> e.Ellipse)
  48
  49     // Process all ellipses and return ellipses ordered from the best score to the worst.
  50     member this.PrunedEllipses : Ellipse list =
  51         if ellipses.Count = 0
  52         then
  53             []
  54         else
  55             // 1) Create a kd-tree from the ellipses list.
  56             let tree = KdTree.Tree.BuildTree (List.ofSeq ellipses)
  57
  58             // 2) Compute the matching score of each ellipses.
  59             let windowSize = radiusMin
  60             for e in ellipses do
  61                 e.Processed <- true
  62                 let areaE = e.Ellipse.Area
  63                 let window = { KdTree.minX = e.Ellipse.Cx - windowSize / 2.f
  64                                KdTree.maxX = e.Ellipse.Cx + windowSize / 2.f
  65                                KdTree.minY = e.Ellipse.Cy - windowSize / 2.f
  66                                KdTree.maxY = e.Ellipse.Cy + windowSize / 2.f }
  67                 for other in tree.Search window do
  68                     if not other.Processed
  69                     then
  70                         let areaOther = other.Ellipse.Area
  71                         match EEOver.EEOverlapArea e.Ellipse other.Ellipse with
  72                         | Some (commonArea, _, _) ->
  73                             let matchingScore = 2.f * commonArea / (areaE + areaOther)
  74                             if matchingScore >= matchingScoreThreshold1
  75                             then
  76                                 other.AddMatchingScore(matchingScore * e.Ellipse.Perimeter)
  77                                 e.AddMatchingScore(matchingScore * other.Ellipse.Perimeter)
  78                         | _ -> ()
  79
  80             // 3) Sort ellipses by their score.
  81             ellipses.Sort(fun e1 e2 -> e2.MatchingScore.CompareTo(e1.MatchingScore))
  82
  83             // 4) Remove ellipses with a low score.
  84             let i = ellipses.BinarySearch(EllipseScoreFlaggedKd(matchingScoreThreshold2, Ellipse(0.f, 0.f, 0.f, 0.f, 0.f)),
  85                                           { new IComparer<EllipseScoreFlaggedKd> with
  86                                                 member this.Compare(e1, e2) = e2.MatchingScore.CompareTo(e1.MatchingScore) }) |> abs
  87             let nbToRemove = ellipses.Count - i
  88             if nbToRemove > 0
  89             then
  90                 for j in i .. nbToRemove - 1 do
  91                     ellipses.[j].Removed <- true
  92                 ellipses.RemoveRange(i, nbToRemove)
  93
  94             // 5) Remove ellipses whose center is into an ellipse with a better score
  95             for e in ellipses do
  96                 if not e.Removed
  97                 then
  98                     let window = { KdTree.minX = e.Ellipse.Cx - e.Ellipse.A
  99                                    KdTree.maxX = e.Ellipse.Cx + e.Ellipse.A
 100                                    KdTree.minY = e.Ellipse.Cy - e.Ellipse.A
 101                                    KdTree.maxY = e.Ellipse.Cy + e.Ellipse.A }
 102                     for other in tree.Search window do
 103                         if not other.Removed && other.MatchingScore < e.MatchingScore
 104                         then
 105                             if e.Ellipse.Scale(scaleOverlapTest).Contains other.Ellipse.Cx other.Ellipse.Cy
 106                             then
 107                                 other.Removed <- true
 108             ellipses.RemoveAll(fun e -> e.Removed) |> ignore
 109
 110             List.ofSeq ellipses |> List.map (fun e -> e.Ellipse)
 111
 112
 113