最简单的一种角点检测算子，但是由于采用了非最大化抑制，效果和OpenCV相当。

  TPointInfo = record
    Info: TPoint;
    w: extended;
    Color: TLabColor;
  end;

  TSinglePointInfoArray = array of TPointInfo;

procedure CornerDetect(Width, Height: longint);
var
  i, j, fi, fj, sum: longint;
begin
  PointCount := 0;
  for i := 7 to Width - 8 do
    for j := 7 to Height - 8 do begin
      sum := 0;
      for fi := i - 7 to i + 7 do
        for fj := j - 7 to j + 7 do
          sum := sum + abs(ImageGray[i, j] - ImageGray[fi, fj]);
      ImagePoint[i, j] := sum div $100;
    end;
  {标准角点检测算子部分}
  for i := 7 to Width - 8 do
    for j := 7 to Height - 8 do begin
      sum := ImagePoint[i, j];
      if sum > $20 then begin
        WBPoint[i, j] := true;
        Inc(PointCount);
        for fi := i - 7 to i + 7 do begin
          for fj := j - 7 to j + 7 do
            if ImagePoint[fi, fj] > sum then begin
              WBPoint[i, j] := false;
              Dec(PointCount);
              break;
            end;
          if not WBPoint[i, j] then break;
        end;
      end else
        WBPoint[i, j] := false;
    end;
  {用非最大化抑制来抑制假角点}
  setlength(CornerPoint, PointCount); fi := 0;
  for i := 7 to Width - 8 do
    for j := 7 to Height - 8 do
      if WBPoint[i, j] then begin
        CornerPoint[fi].Info.X := i;
        CornerPoint[fi].Info.Y := j;
        Inc(fi);
      end;
  {输出为一个点序列}
end;

输入的ImageGray为图像的灰度描述，WBPoint为Boolean数组，ImagePoint为标准角点检测算子运行后的检测值。