yGradientData.[h - 1, c, 0] <- 0.0
use magnitudes = new Matrix<float>(xGradient.Size)
- CvInvoke.CartToPolar(xGradient, yGradient, magnitudes, new Mat()) // Compute the magnitudes (without angles).
+ use angles = new Matrix<float>(xGradient.Size)
+ CvInvoke.CartToPolar(xGradient, yGradient, magnitudes, angles) // Compute the magnitudes (without angles).
let thresholdHigh, thresholdLow =
let sensibility = 0.1
// Non-maximum suppression.
use nms = new Matrix<byte>(xGradient.Size)
- nms.SetValue(1.0)
for i in 0 .. h - 1 do
nms.Data.[i, 0] <- 0uy
for j in 1 .. w - 2 do
let vx = xGradient.Data.[i, j, 0]
let vy = yGradient.Data.[i, j, 0]
- let angle =
- let a = atan2 vy vx
- if a < 0.0 then 2. * Math.PI + a else a
-
- let mNeigbors (sign: int) : float =
- if angle < Math.PI / 8. || angle >= 15.0 * Math.PI / 8. then magnitudes.Data.[i, j + sign]
- elif angle < 3.0 * Math.PI / 8. then magnitudes.Data.[i + sign, j + sign]
- elif angle < 5.0 * Math.PI / 8. then magnitudes.Data.[i + sign, j]
- elif angle < 7.0 * Math.PI / 8. then magnitudes.Data.[i + sign, j - sign]
- elif angle < 9.0 * Math.PI / 8. then magnitudes.Data.[i, j - sign]
- elif angle < 11.0 * Math.PI / 8. then magnitudes.Data.[i - sign, j - sign]
- elif angle < 13.0 * Math.PI / 8. then magnitudes.Data.[i - sign, j]
- else magnitudes.Data.[i - sign, j + sign]
-
- let m = magnitudes.Data.[i, j]
- if m < mNeigbors 1 || m < mNeigbors -1 || m < thresholdLow
+ if vx <> 0. || vy <> 0.
then
- nms.Data.[i, j] <- 0uy
+ let angle = angles.[i, j]
+
+ let vx', vy' = abs vx, abs vy
+ let ratio2 = if vx' > vy' then vy' / vx' else vx' / vy'
+ let ratio1 = 1. - ratio2
+
+ let mNeigbors (sign: int) : float =
+ if angle < Math.PI / 4.
+ then
+ ratio1 * magnitudes.Data.[i, j + sign] + ratio2 * magnitudes.Data.[i + sign, j + sign]
+ elif angle < Math.PI / 2.
+ then
+ ratio2 * magnitudes.Data.[i + sign, j + sign] + ratio1 * magnitudes.Data.[i + sign, j]
+ elif angle < 3.0 * Math.PI / 4.
+ then
+ ratio1 * magnitudes.Data.[i + sign, j] + ratio2 * magnitudes.Data.[i + sign, j - sign]
+ elif angle < Math.PI
+ then
+ ratio2 * magnitudes.Data.[i + sign, j - sign] + ratio1 * magnitudes.Data.[i, j - sign]
+ elif angle < 5. * Math.PI / 4.
+ then
+ ratio1 * magnitudes.Data.[i, j - sign] + ratio2 * magnitudes.Data.[i - sign, j - sign]
+ elif angle < 3. * Math.PI / 2.
+ then
+ ratio2 * magnitudes.Data.[i - sign, j - sign] + ratio1 * magnitudes.Data.[i - sign, j]
+ elif angle < 7. * Math.PI / 4.
+ then
+ ratio1 * magnitudes.Data.[i - sign, j] + ratio2 * magnitudes.Data.[i - sign, j + sign]
+ else
+ ratio2 * magnitudes.Data.[i - sign, j + sign] + ratio1 * magnitudes.Data.[i, j + sign]
+
+ let m = magnitudes.Data.[i, j]
+ if m >= thresholdLow && m > mNeigbors 1 && m > mNeigbors -1
+ then
+ nms.Data.[i, j] <- 1uy
- // suppressMConnections nms // It's not usefull for the rest of the process (ellipse detection).
+ // suppressMConnections nms // It's not helpful for the rest of the process (ellipse detection).
let edges = new Matrix<byte>(xGradient.Size)
nms.Data.[ni, nj] <- 0uy
toVisit.Push(Point(nj, ni))
-
edges, xGradient, yGradient
type Points = HashSet<Point>
-let drawPoints (img: Image<Gray, byte>) (points: Points) (intensity: byte) =
+let drawPoints (img: Image<Gray, 'TDepth>) (points: Points) (intensity: 'TDepth) =
for p in points do
img.Data.[p.Y, p.X, 0] <- intensity
| Maxima = 1
| Minima = 2
-let findExtremum (img: Image<Gray,
byte>) (extremumType: ExtremumType) : IEnumerable<Points> =
+let findExtremum (img: Image<Gray,
'TDepth>) (extremumType: ExtremumType) : IEnumerable<Points> =
let w = img.Width
let h = img.Height
let se = [| -1, 0; 0, -1; 1, 0; 0, 1 |]
result.Select(fun l -> Points(l))
-let findMaxima (img: Image<Gray,
byte>) : IEnumerable<Points> =
+let findMaxima (img: Image<Gray,
'TDepth>) : IEnumerable<Points> =
findExtremum img ExtremumType.Maxima
-let findMinima (img: Image<Gray, byte>) : IEnumerable<Points> =
+
+let findMinima (img: Image<Gray, 'TDepth>) : IEnumerable<Points> =
findExtremum img ExtremumType.Minima
let areaClose (img: Image<Gray, byte>) (area: int) =
areaOperation img area AreaOperation.Closing
+[<AllowNullLiteral>]
+type Island (cmp: IComparer<float32>) =
+ member val Shore = Heap.Heap<float32, Point>(cmp) with get
+ member val Level = 0.f with get, set
+ member val Surface = 0 with get, set
+
+
+let private areaOperationF (img: Image<Gray, float32>) (area: int) (op: AreaOperation) =
+ let w = img.Width
+ let h = img.Height
+ let earth = img.Data
+ let se = [| -1, 0; 0, -1; 1, 0; 0, 1 |]
+
+ let comparer = if op = AreaOperation.Opening
+ then { new IComparer<float32> with member this.Compare(v1, v2) = v1.CompareTo(v2) }
+ else { new IComparer<float32> with member this.Compare(v1, v2) = v2.CompareTo(v1) }
+
+ let ownership: Island[,] = Array2D.create h w null
+
+ // Initialize islands with their shore.
+ let islands = List<Island>()
+ let extremum = img |> if op = AreaOperation.Opening then findMaxima else findMinima
+ for e in extremum do
+ let island =
+ let p = e.First()
+ Island(comparer, Level = earth.[p.Y, p.X, 0], Surface = e.Count)
+ islands.Add(island)
+ let shorePoints = Points()
+ for p in e do
+ ownership.[p.Y, p.X] <- island
+ for i, j in se do
+ let ni = i + p.Y
+ let nj = j + p.X
+ let neighbor = Point(nj, ni)
+ if ni >= 0 && ni < h && nj >= 0 && nj < w && ownership.[ni, nj] = null && not (shorePoints.Contains(neighbor))
+ then
+ shorePoints.Add(neighbor) |> ignore
+ island.Shore.Add earth.[ni, nj, 0] neighbor
+
+ for island in islands do
+ let mutable stop = island.Shore.IsEmpty
+
+ // 'true' if 'p' is owned or adjacent to 'island'.
+ let ownedOrAdjacent (p: Point) : bool =
+ ownership.[p.Y, p.X] = island ||
+ (p.Y > 0 && ownership.[p.Y - 1, p.X] = island) ||
+ (p.Y < h - 1 && ownership.[p.Y + 1, p.X] = island) ||
+ (p.X > 0 && ownership.[p.Y, p.X - 1] = island) ||
+ (p.X < w - 1 && ownership.[p.Y, p.X + 1] = island)
+
+ while not stop && island.Surface < area do
+ let level, next = island.Shore.Max
+ let other = ownership.[next.Y, next.X]
+ if other = island // During merging, some points on the shore may be owned by the island itself -> ignored.
+ then
+ island.Shore.RemoveNext ()
+ else
+ if other <> null
+ then // We touching another island.
+ if island.Surface + other.Surface >= area
+ then
+ stop <- true
+ else // We can merge 'other' into 'surface'.
+ island.Surface <- island.Surface + other.Surface
+ island.Level <- if comparer.Compare(island.Level, other.Level) > 0 then island.Level else other.Level
+ for l, p in other.Shore do
+ let mutable currentY = p.Y + 1
+ while currentY < h && ownership.[currentY, p.X] = other do
+ ownership.[currentY, p.X] <- island
+ currentY <- currentY + 1
+ island.Shore.Add l p
+ other.Shore.Clear()
+
+ elif comparer.Compare(level, island.Level) > 0
+ then
+ stop <- true
+ else
+ island.Shore.RemoveNext ()
+ for i, j in se do
+ let ni = i + next.Y
+ let nj = j + next.X
+ if ni < 0 || ni >= h || nj < 0 || nj >= w
+ then
+ island.Surface <- Int32.MaxValue
+ stop <- true
+ else
+ let neighbor = Point(nj, ni)
+ if not <| ownedOrAdjacent neighbor
+ then
+ island.Shore.Add earth.[ni, nj, 0] neighbor
+ if not stop
+ then
+ ownership.[next.Y, next.X] <- island
+ island.Level <- level
+ island.Surface <- island.Surface + 1
+
+ for i in 0 .. h - 1 do
+ for j in 0 .. w - 1 do
+ let island = ownership.[i, j]
+ if island <> null
+ then
+ earth.[i, j, 0] <- island.Level
+ ()
+
+
+let areaOpenF (img: Image<Gray, float32>) (area: int) =
+ areaOperationF img area AreaOperation.Opening
+
+let areaCloseF (img: Image<Gray, float32>) (area: int) =
+ areaOperationF img area AreaOperation.Closing
+
// A simpler algorithm than 'areaOpen' but slower.
let areaOpen2 (img: Image<Gray, byte>) (area: int) =
let w = img.Width
projects / master-thesis.git / blobdiff