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 // All ellipsee with a score below this is removed.
  16 let matchingScoreThreshold2 = 1. / 100.
  17
  18 type private EllipseScoreFlaggedKd (matchingScore: float, e: Ellipse) =
  19     let mutable matchingScore = matchingScore
  20     let perimeter = e.Perimeter
  21
  22     member this.Ellipse = e
  23
  24     member this.MatchingScore = matchingScore
  25
  26     // The score is proportional to the perimeter because large ellipse will receive more votes.
  27     member this.AddMatchingScore(score: float) =
  28         matchingScore <- matchingScore + score / perimeter
  29
  30     member val Processed = false with get, set
  31     member val Removed = false with get, set
  32
  33     interface KdTree.I2DCoords with
  34         member this.X = this.Ellipse.Cx
  35         member this.Y = this.Ellipse.Cy
  36
  37
  38 type MatchingEllipses (radiusMin: float) =
  39     let ellipses = List<EllipseScoreFlaggedKd>()
  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)
  75                                 e.AddMatchingScore(matchingScore)
  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 wich have 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(0.8).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