// Search the image for consecutive rows of mostly white
function FindConsecutiveWhiteRows(MinWhiteValue: Integer; MinConsecutiveWhiteRows: Integer; out WhiteRowsStart: Integer; out WhiteRowsEnd: Integer): Boolean; 
var
  x, y: Integer;
  pPix: PRGB;
  Gray: Byte;
  rowIsWhite: Boolean;
  consecutiveWhiteRows: Integer;
begin
  Result := False;
  WhiteRowsStart := 0;
  WhiteRowsEnd   := 0;

  consecutiveWhiteRows := 0;
  for y := 0 to ImageEnView1.IEBitmap.Height - 1 do
  begin
    pPix := ImageEnView1.IEBitmap.ScanLine[ y ];
    rowIsWhite := True;
    for x := 0 to ImageEnView1.IEBitmap.Width - 1 do
    begin
      if (pPix^.R < White_MinWhiteValue ) or (pPix^.G < MinWhiteValue ) or (pPix^.B < MinWhiteValue ) then
      begin    
        rowIsWhite := False;
        Break;
      end;
      inc( pPix );
    end;
    if rowIsWhite then 
      inc( consecutiveWhiteRows )
    else
      consecutiveWhiteRows := 0;

    if consecutiveWhiteRows >= MinConsecutiveWhiteRows then
    begin
      Result := True;
      WhiteRowsStart := y - consecutiveWhiteRows + 1;
      WhiteRowsEnd   := y;
      exit;
    end;
  end;
end;