Hough transformation for Kreise

[bernhard_LA]

Danke für die schnelle Hilfe, der Port in eine 2D Array analog zur Linienerkennung ist fertig.

Ich kann zwar den Akku vom TestBild reproduzieren bei vielen anderen Testbeispielen bekomme ich aber kein sinnvolles Ergebnis



///
/// Hough transformation for circle detection
///
///
/// AnalysisBitmap : TBitMap; -> the image for hough tranmsformation
/// aHoughResult : THoughResult -> the result of the Hough transformation array of array of integer
/// r : Integer; -> the search radius
///
///


procedure Hough_CircleDetection ( AnalysisBitmap : TBitMap; var aHoughResult : THoughResult ; r : Integer );
var x,y, x0,y0 : integer;
ImageWidth : integer;
ImageHeight : Integer;
max_d : Integer;
help : Real;
theta : Integer;
max_theta : Integer;
Box_LL : FPoint;
Box_UR : FPoint;
TestPoint : TPoint;
begin


/// size of hough array
ImageWidth := AnalysisBitmap.Width;
ImageHeight:= AnalysisBitmap.Height;

///
Box_LL.X := 0;
Box_UR.y := 0;

Box_UR.X := ImageWidth;
Box_UR.Y := ImageHeight;

max_theta := 360;
// a // b
SetLength(aHoughResult,ImageWidth, ImageHeight );

// For all rows in image:
for y:=0 to AnalysisBitmap.Height-1 do
begin

// For all pixel in one row :
for x:=0 to AnalysisBitmap.Width-1 do
begin

// Is there a point ?
if IsPixel(x,y, AnalysisBitmap, 128 ) then
begin

for theta:=0 to max_theta do
begin

TestPoint.x := round ( x - r * cos(theta*PI/max_theta) );
TestPoint.y := round ( y - r * sin(theta*PI/max_theta));

// if IsPointInBox( Box_LL , Box_UR, testPoint ) then Inc(aHoughResult[x,y]);

if ((testPoint.x < ImageWidth) and (testPoint.x > 0 ) and
(testPoint.y < ImageHeight ) and (testPoint.y > 0 ) ) then Inc(aHoughResult[TestPoint.x,TestPoint.y]);

end;
end;
end;
end;


end