Remove noise, dots and image strokes

Question

Remove noise, dots and image strokes

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#1 by (4 votes)

6

I'd like to know how I can process a captcha image to remove noise, traces, and dots. Here are some examples of how you are and how I would like you to stay.

Original Image:

AdjustedImage:

delphi object-pascal

asked by anonymous 23.11.2015 / 13:33

1 answer

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score 4 · Accepted Answer

Follow procedure to perform Noise Removal, Dots and some dashes!

Add 1 component TImage and 1 component TButton , in TImage1 load a BMP image (for pixel the pixel is the best format, then the procedure is all over that format )

procedure frmTeste.btnCorrigirClick(Sender: TObject);
var
  X, Y : Integer;
  vBmpTemp : TBitmap;
begin
  vBmpTemp := TBitmap.Create;
  vBmpTemp.Assign(Image.Picture.Bitmap);
  for X := 0 to Image.Width - 1 do
  begin
    for Y := 0 to Image.Height - 1 do
    begin
      if ((Image.Canvas.Pixels[X, Y] >=  $00000000)  and
          (Image.Canvas.Pixels[X, Y] <=  $00999999)) or
          (Image.Canvas.Pixels[X, Y]  =  $00FEFEFE)  or
          (Image.Canvas.Pixels[X, Y]  =  $00FAFAFA)  or
          (Image.Canvas.Pixels[X, Y]  =  clBlack)    then
      begin
        if ((Image.Canvas.Pixels[X - 1, Y] >=  $00000000)  and
            (Image.Canvas.Pixels[X + 1, Y] <=  $00999999)) then
        begin
          vBmpTemp.Canvas.Pixels[X, Y] := Image.Canvas.Pixels[X, Y];
        end;
      end;
    end;
  end;

  Image.Picture := nil;

  for X := 0 to vBmpTemp.Width - 1 do
  begin
    for Y := 0 to vBmpTemp.Height - 1 do
    begin
      if ((vBmpTemp.Canvas.Pixels[X, Y] >=  $00000000)  and
          (vBmpTemp.Canvas.Pixels[X, Y] <=  $00999999)) or
          (vBmpTemp.Canvas.Pixels[X, Y]  =  $00FEFEFE)  or
          (vBmpTemp.Canvas.Pixels[X, Y]  =  $00FAFAFA)  or
          (vBmpTemp.Canvas.Pixels[X, Y]  =  clBlack)    then
      begin
        if ((vBmpTemp.Canvas.Pixels[X - 1, Y] >=  $00000000)  and
            (vBmpTemp.Canvas.Pixels[X + 1, Y] <=  $00999999)) then
        begin
          Image.Canvas.Pixels[X, Y] := vBmpTemp.Canvas.Pixels[X, Y];
        end;
      end;
    end;
  end;
end;

What I did is very simple, I'm going through the whole image pixels to pixels, if I find a sequence of colors I move it to TImage .

Each click on the button clears the image more and more! I await feedback!