function SSD(Canvas1, Canvas2: TCanvas; Pixel:integer):Single;
var
  x, y:integer;
  Gamma, Intensity1, PixelValue1, Intensity2, PixelValue2:single;
  R1, G1, B1, R2, G2, B2, Grayscale1, Grayscale2:byte;
  MyColor1, MyColor2:TColor;

  SSDvalue:Extended;
begin
  SSDvalue:=0.0;
  Gamma:=2.2;

  for x:=0 to (Pixel-1) do
  begin
    for y:=0 to (Pixel-1) do
    begin
      MyColor1:=Canvas1.Pixels[x, y];
      TColor2RGB(MyColor1, R1, G1, B1);

      MyColor2:=Canvas2.Pixels[x, y];
      TColor2RGB(MyColor2, R2, G2, B2);

      // Graustufenbild 1 (Umrechnung auf L*a*b - Farbraum)
      Intensity1:=0.2126 * Power(R1/255, Gamma) + 0.7152 * Power(G1/255, Gamma) + 0.0722 * Power(B1/255, Gamma);
      Grayscale1:=255-round(116*Power(Intensity1, 1/3)-16);
      PixelValue1:=Grayscale1/255;

      // Graustufenbild 2 (Umrechnung auf L*a*b - Farbraum)
      Intensity2:=0.2126 * Power(R2/255, Gamma) + 0.7152 * Power(G2/255, Gamma) + 0.0722 * Power(B2/255, Gamma);
      Grayscale2:=255-round(116*Power(Intensity2, 1/3)-16);
      PixelValue2:=Grayscale2/255;

      // SumOfSquaredDifferences (SSD) (wird MINIMAL (<1) bei guter Übereinstimmung)
      SSDvalue:=SSDvalue+Power((PixelValue1-PixelValue2), 2);
    end;
  end;

  result:=SSDvalue;
end;