unit filterMedian;
(* ***** BEGIN LICENSE BLOCK *****
 * Copyright (C) 2004 Durand Emmanuel
 * Copyright (C) 2004 Burgel Eric
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Contact :
 *   filters@edurand.com
 *   filters@burgel.com
 * Site :
 *   http://filters.sourceforge.net/
 *
 * ***** END LICENSE BLOCK ***** *)

{
 edurand (filters@edurand.com)
}

interface
uses
  filter, fparameters, image, SysUtils;

type
  TFilterMedian = class(TFilter)
  public
    constructor Create; override;
    destructor Destroy; override;
    procedure Run(); override;
  private
    parameterPrecision : TParameterInteger;
    parameterImageIn, parameterImageOut : TParameterImage;
    procedure _run();
  end;

implementation
uses
  imageIO, Math;

constructor TFilterMedian.Create;
begin
  inherited;
  parameterImageIn:=addParameterImage('inImage','image to process');
  parameterImageOut:=addParameterImage('outImage','output image');
  parameterPrecision:=addParameterInteger('precision','',0,10,2);
end;

destructor TFilterMedian.Destroy;
begin
end;

procedure TFilterMedian.Run();
begin
  if (parameterImageIn.Image<>nil) and (parameterImageOut.Image<>nil) then begin
    _run();
  end;
end;

procedure TFilterMedian._run();
var
  pSrc, PDest : PColor32Array;
  w,h :Integer;
  value : Integer;
  tIntensity : Integer;
  neighbor :Integer;
  imageSrcRow, imageSrcCol : Integer;
  imageSrcRowmax, imageSrcColmax : Integer;
  imageSrcNeighborRow, imageSrcNeighborCol : Integer;
  imageSrcNeighborRowmin, imageSrcNeighborColmin : Integer;
  imageSrcNeighborRowmax, imageSrcNeighborColmax : Integer;
  table : array [0..255] of Integer;
  tableColor : array [0..255] of TColor32;
  indexOfMedian : Integer;
  counter, counterMax : Integer;
  indexMin, indexMax : Integer;
begin
  h:=parameterImageIn.Image.Height;
  w:=parameterImageIn.Image.Width;
  neighbor:=parameterPrecision.Value;
  pSrc:=parameterImageIn.Image.Bits;
  imageSrcRowmax:=h-1;
  imageSrcColmax:=w-1;
  for imageSrcRow:=0 to imageSrcRowmax do begin
    pDest:=parameterImageOut.Image.Bits;
    Inc(pDest,imageSrcRow*w);
    for imageSrcCol:=0 to imageSrcColmax do begin
      FillChar(table,256*SizeOf(Integer),0);
      //FillChar(table,256*SizeOf(Integer),0);
      //FillChar(tableColor,256*SizeOf(TColor32),0);
      counterMax:=0;
      indexMin:=256;
      indexMax:=-1;
      //
      imageSrcNeighborRowmin:=imageSrcRow-neighbor; if imageSrcNeighborRowmin<0 then imageSrcNeighborRowmin:=0;
      imageSrcNeighborColmin:=imageSrcCol-neighbor; if imageSrcNeighborColmin<0 then imageSrcNeighborColmin:=0;
      imageSrcNeighborRowmax:=imageSrcRow+neighbor; if imageSrcNeighborRowmax>imageSrcRowmax then imageSrcNeighborRowmax:=imageSrcRowmax;
      imageSrcNeighborColmax:=imageSrcCol+neighbor; if imageSrcNeighborColmax>imageSrcColmax then imageSrcNeighborColmax:=imageSrcColmax;
      for imageSrcNeighborRow:=imageSrcNeighborRowmin to imageSrcNeighborRowmax do begin
        for imageSrcNeighborCol:=imageSrcNeighborColmin to imageSrcNeighborColmax do begin
          value:=pSrc[imageSrcNeighborRow*w+imageSrcNeighborCol];
          tIntensity:=Intensity(value);
          Inc(table[tIntensity]);
          tableColor[tIntensity]:=value;// ok, eraze last one if exist, but not inportant
          Inc(counterMax);
          if tIntensity<indexMin then indexMin:=tIntensity;
          if tIntensity>indexMax then indexMax:=tIntensity;
        end;
      end;
      // search the median
      counterMax:=Trunc(counterMax/2)+1;
      counter:=0;
      indexOfMedian:=indexMin;
      while (indexOfMedian<=indexMax) and (counter<=counterMax) do begin
        Inc(counter,table[indexOfMedian]);
        Inc(indexOfMedian);
      end;
      Dec(indexOfMedian);
      // set the color of the nucleus to the color of the median
      pDest^[0]:=tableColor[indexOfMedian];
      Inc(pDest);
    end;
  end;
end;

{ method by ordering
procedure TFilterMedian._run();
var
  pSrc, PDest : PColor32Array;
  w,h :Integer;
  value : Integer;
  tIntensity : Integer;
  neighbor :Integer;
  imageSrcRow, imageSrcCol : Integer;
  imageSrcRowmax, imageSrcColmax : Integer;
  imageSrcNeighborRow, imageSrcNeighborCol : Integer;
  imageSrcNeighborRowmin, imageSrcNeighborColmin : Integer;
  imageSrcNeighborRowmax, imageSrcNeighborColmax : Integer;
  indexOfMedian : Integer;
  counter, counterMax : Integer;
  table, tableOrdered : array of Integer;
  tableColor : array of TColor32;
  i, j : Integer;
  max, indexMax : Integer;
  c : TColor32;
begin
  h:=parameterImageIn.Image.Height;
  w:=parameterImageIn.Image.Width;
  neighbor:=parameterPrecision.Value;
  counterMax:=sqr(neighbor*2+1);
  SetLength(table,counterMax);
  SetLength(tableColor,counterMax);
  SetLength(tableOrdered,counterMax);
  pSrc:=parameterImageIn.Image.Bits;
  imageSrcRowmax:=h-1;
  imageSrcColmax:=w-1;
  for imageSrcRow:=0 to imageSrcRowmax do begin
    pDest:=parameterImageOut.Image.Bits;
    Inc(pDest,imageSrcRow*w);
    for imageSrcCol:=0 to imageSrcColmax do begin
      counter:=0;
      //
      imageSrcNeighborRowmin:=imageSrcRow-neighbor; if imageSrcNeighborRowmin<0 then imageSrcNeighborRowmin:=0;
      imageSrcNeighborColmin:=imageSrcCol-neighbor; if imageSrcNeighborColmin<0 then imageSrcNeighborColmin:=0;
      imageSrcNeighborRowmax:=imageSrcRow+neighbor; if imageSrcNeighborRowmax>imageSrcRowmax then imageSrcNeighborRowmax:=imageSrcRowmax;
      imageSrcNeighborColmax:=imageSrcCol+neighbor; if imageSrcNeighborColmax>imageSrcColmax then imageSrcNeighborColmax:=imageSrcColmax;
      for imageSrcNeighborRow:=imageSrcNeighborRowmin to imageSrcNeighborRowmax do begin
        for imageSrcNeighborCol:=imageSrcNeighborColmin to imageSrcNeighborColmax do begin
          value:=pSrc[imageSrcNeighborRow*w+imageSrcNeighborCol];
          tIntensity:=Intensity(value);
          table[counter]:=tIntensity;
          tableColor[counter]:=value;
          Inc(counter);
        end;
      end;
      indexOfMedian:=Trunc((counter-1)/2)+1;
      for i:=0 to indexOfMedian do begin
        max:=-1;
        j:=0;
        while j<counterMax do begin
          if table[j]>max then begin
            max:=table[j];
            indexMax:=j;
          end;
          Inc(j);
        end;
        table[indexMax]:=-1;
      end;
      // search the median
      // set the color of the nucleus to the color of the median
      pDest^[0]:=tableColor[indexMax];
      Inc(pDest);
    end;
  end;
end;
}
end.