public int ComputeValue(Point WinTopLeft, float SizeRatio, IntegralImage Image)
{
/*
* a ------- b ------- c
* - - -
* - R1 - R2 -
* - - -
* d ------- e ------- f
* - - -
* - R3 - R4 -
* - - -
* g ------- h ------- i
* S(R1) = e - (b + d) + a
* S(R2) = f - (c + e) + b
* S(R3) = h - (e + g) + d
* S(R4) = i - (f + h) + e
*/
var scaledFrame = this.Frame.Scale(SizeRatio);
var topLeft = scaledFrame.TopLeft.NestedPoint(WinTopLeft);
var rectsWidth = scaledFrame.Width / 2;
var rectsHeight = scaledFrame.Height / 2;
var aCoords = topLeft;
var bCoords = aCoords.Translate(rectsWidth, 0);
var cCoords = bCoords.Translate(rectsWidth, 0);
var dCoords = aCoords.Translate(0, rectsHeight);
var eCoords = dCoords.Translate(rectsWidth, 0);
var fCoords = eCoords.Translate(rectsWidth, 0);
var gCoords = dCoords.Translate(0, rectsHeight);
var hCoords = gCoords.Translate(rectsWidth, 0);
var iCoords = hCoords.Translate(rectsWidth, 0);
var a = Image.GetValue(aCoords);
var b = Image.GetValue(bCoords);
var c = Image.GetValue(cCoords);
var d = Image.GetValue(dCoords);
var e = Image.GetValue(eCoords);
var f = Image.GetValue(fCoords);
var g = Image.GetValue(gCoords);
var h = Image.GetValue(hCoords);
var i = Image.GetValue(iCoords);
var sumR1 = e - (b + d) + a;
var sumR2 = f - (c + e) + b;
var sumR3 = h - (e + g) + d;
var sumR4 = i - (f + h) + e;
return (int) (sumR1 - sumR2 - sumR3 + sumR4);
}
public int ComputeValue(Point WinTopLeft, float SizeRatio, IntegralImage Image)
{
/*
* a ------- b
* - -
* - R1 -
* - -
* c ------- d
* - -
* - R2 -
* - -
* e ------- f
* S(R1) = d - (b + c) + a
* S(R2) = f - (d + e) + c
*/
var scaledFrame = this.Frame.Scale(SizeRatio);
var topLeft = scaledFrame.TopLeft.NestedPoint(WinTopLeft);
var rectsWidth = scaledFrame.Width;
var rectsHeight = scaledFrame.Height / 2;
var aCoords = topLeft;
var bCoords = aCoords.Translate(rectsWidth, 0);
var cCoords = aCoords.Translate(0, rectsHeight);
var dCoords = cCoords.Translate(rectsWidth, 0);
var eCoords = cCoords.Translate(0, rectsHeight);
var fCoords = eCoords.Translate(rectsWidth, 0);
var a = Image.GetValue(aCoords);
var b = Image.GetValue(bCoords);
var c = Image.GetValue(cCoords);
var d = Image.GetValue(dCoords);
var e = Image.GetValue(eCoords);
var f = Image.GetValue(fCoords);
var sumR1 = d - (b + c) + a;
var sumR2 = f - (d + e) + c;
return (int) (sumR2 - sumR1);
}
/// <summary>
/// Retourne la dispertion de la valeur des pixels
/// contenus dans la fenêtre/
/// </summary>
private int GetDeviation(IntegralImage Image, IntegralImage SquaredImage)
{
/*
* a -------- b
* - -
* - Window -
* - -
* c -------- d
*
* sum = d - (b + c) + a
* avg = sum / nPixs
* deriv = sqrt(sum(pixs²) / nPixs - avg(pixs))
*/
var nPixs = this.Width * this.Height;
var aCoords = this.TopLeft;
var bCoords = aCoords.Translate(this.Width, 0);
var cCoords = aCoords.Translate(0, this.Height);
var dCoords = cCoords.Translate(this.Width, 0);
var a = Image.GetValue(aCoords);
var b = Image.GetValue(bCoords);
var c = Image.GetValue(cCoords);
var d = Image.GetValue(dCoords);
var squaredA = SquaredImage.GetValue(aCoords);
var squaredB = SquaredImage.GetValue(bCoords);
var squaredC = SquaredImage.GetValue(cCoords);
var squaredD = SquaredImage.GetValue(dCoords);
var sum = d - (b + c) + a;
var squaredSum = squaredD - (squaredB + squaredC) + squaredA;
var avg = sum / nPixs;
var variance = squaredSum / nPixs - avg*avg;
// Min 1 to remove division by zero
if (variance > 0)
return (int) Math.Sqrt(variance);
else
return 1;
}