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 let matchingScoreThreshold1 = 0.6
  14
  15 let scaleOverlapTest = 0.8
  16
  17 type private EllipseScoreFlaggedKd (matchingScore: float, e: Ellipse) =
  18     let mutable matchingScore = matchingScore
  19
  20     member this.Ellipse = e
  21
  22     member this.MatchingScore = matchingScore
  23
  24     member this.AddMatchingScore(score: float) =
  25         matchingScore <- matchingScore + score
  26
  27     member val Processed = false with get, set
  28     member val Removed = false with get, set
  29
  30     interface KdTree.I2DCoords with
  31         member this.X = this.Ellipse.Cx
  32         member this.Y = this.Ellipse.Cy
  33
  34
  35 type MatchingEllipses (radiusMin: float) =
  36     let ellipses = List<EllipseScoreFlaggedKd>()
  37
  38     // All ellipses with a score below this are removed.
  39     let matchingScoreThreshold2 = 20. * radiusMin
  40
  41     member this.Add (e: Ellipse) =
  42         ellipses.Add(EllipseScoreFlaggedKd(0.0, e))
  43
  44     member this.Ellipses : Ellipse list =
  45         List.ofSeq ellipses |> List.map (fun e -> e.Ellipse)
  46
  47     // Process all ellipses and return ellipses ordered from the best score to the worst.
  48     member this.PrunedEllipses : Ellipse list =
  49         if ellipses.Count = 0
  50         then
  51             []
  52         else
  53             // 1) Create a kd-tree from the ellipses list.
  54             let tree = KdTree.Tree.BuildTree (List.ofSeq ellipses)
  55
  56             // 2) Compute the matching score of each ellipses.
  57             let windowSize = radiusMin
  58             for e in ellipses do
  59                 e.Processed <- true
  60                 let areaE = e.Ellipse.Area
  61                 let window = { KdTree.minX = e.Ellipse.Cx - windowSize / 2.0
  62                                KdTree.maxX = e.Ellipse.Cx + windowSize / 2.0
  63                                KdTree.minY = e.Ellipse.Cy - windowSize / 2.0
  64                                KdTree.maxY = e.Ellipse.Cy + windowSize / 2.0 }
  65                 for other in tree.Search window do
  66                     if not other.Processed
  67                     then
  68                         let areaOther = other.Ellipse.Area
  69                         match EEOver.EEOverlapArea e.Ellipse other.Ellipse with
  70                         | Some (commonArea, _, _) ->
  71                             let matchingScore = 2.0 * commonArea / (areaE + areaOther)
  72                             if matchingScore >= matchingScoreThreshold1
  73                             then
  74                                 other.AddMatchingScore(matchingScore * e.Ellipse.Perimeter)
  75                                 e.AddMatchingScore(matchingScore * other.Ellipse.Perimeter)
  76                         | _ -> ()
  77
  78             // 3) Sort ellipses by their score.
  79             ellipses.Sort(fun e1 e2 -> e2.MatchingScore.CompareTo(e1.MatchingScore))
  80
  81             // 4) Remove ellipses with a low score.
  82             let i = ellipses.BinarySearch(EllipseScoreFlaggedKd(matchingScoreThreshold2, Ellipse(0.0, 0.0, 0.0, 0.0, 0.0)),
  83                                           { new IComparer<EllipseScoreFlaggedKd> with
  84                                                 member this.Compare(e1, e2) = e2.MatchingScore.CompareTo(e1.MatchingScore) }) |> abs
  85             let nbToRemove = ellipses.Count - i
  86             if nbToRemove > 0
  87             then
  88                 for j in i .. nbToRemove - 1 do
  89                     ellipses.[j].Removed <- true
  90                 ellipses.RemoveRange(i, nbToRemove)
  91
  92             // 5) Remove ellipses whose center is into an ellipse with a better score
  93             for e in ellipses do
  94                 if not e.Removed
  95                 then
  96                     let window = { KdTree.minX = e.Ellipse.Cx - e.Ellipse.A
  97                                    KdTree.maxX = e.Ellipse.Cx + e.Ellipse.A
  98                                    KdTree.minY = e.Ellipse.Cy - e.Ellipse.A
  99                                    KdTree.maxY = e.Ellipse.Cy + e.Ellipse.A }
 100                     for other in tree.Search window do
 101                         if not other.Removed && other.MatchingScore < e.MatchingScore
 102                         then
 103                             if e.Ellipse.Scale(scaleOverlapTest).Contains other.Ellipse.Cx other.Ellipse.Cy
 104                             then
 105                                 other.Removed <- true
 106             ellipses.RemoveAll(fun e -> e.Removed) |> ignore
 107
 108             List.ofSeq ellipses |> List.map (fun e -> e.Ellipse)
 109
 110
 111