# Lazarus

## Programming => Graphics and Multimedia => Graphics => Topic started by: yahoo000 on March 05, 2021, 01:00:44 am

Title: How to generate multiple images/save to files .. with random noise ?
Post by: yahoo000 on March 05, 2021, 01:00:44 am
How to generate multiple images/save to files .. with random noise ?

Is there any free component with some examples how to do it ?

so I got one original image "image1.jpg" and I would like to generate 300 images with random noise "image1_random1.jpg" "image1_random2.jpg"

thanks for help.
Title: Re: How to generate multiple images/save to files .. with random noise ?
Post by: lainz on March 05, 2021, 02:04:40 am
Yes, using BGRABitmap is easy

Color noise:

Code: Pascal  [Select][+][-]
1. procedure Noise(Bitmap: TBGRABitmap);
2. var
3.   i: integer;
4.   p: PBGRAPixel;
5. begin
6.   p := Bitmap.Data;
7.
8.   for i := Bitmap.NBPixels - 1 downto 0 do
9.   begin
10.     p^.red := Random(256);
11.     p^.green := Random(256);
12.     p^.blue := Random(256);
13.     //p^.alpha := Random(256);
14.     Inc(p);
15.   end;
16. end;

Black and white noise:

Code: Pascal  [Select][+][-]
1. procedure NoiseBW(Bitmap: TBGRABitmap);
2. var
3.   i: integer;
4.   p: PBGRAPixel;
5.   c: byte;
6. begin
7.   p := Bitmap.Data;
8.
9.   for i := Bitmap.NBPixels - 1 downto 0 do
10.   begin
11.     c := Random(2);
12.     p^.red := c + 255;
13.     p^.green := c + 255;
14.     p^.blue := c + 255;
15.     //p^.alpha := Random(256);
16.     Inc(p);
17.   end;
18. end;

Just do something like this:

Code: Pascal  [Select][+][-]
1. var
2.   i: integer;
3.   bmp: TBGRABitmap;
4. begin
5.   bmp := TBGRABitmap.Create(640,480);
6.   for i:=1 to 300 do
7.   begin
8.     NoiseBW(bmp);
9.     bmp.SaveToFile('image1_random' + i.ToString() + '.jpg');
10.   end;
11.   bmp.Free;
12. end;

Edit: add to uses clause BGRABitmap, BGRABitmapTypes.
Title: Re: How to generate multiple images/save to files .. with random noise ?
Post by: lainz on March 05, 2021, 02:08:19 am
But I don't get if you want to generate random noise over the image with alpha perhaps?
- If this is the case, you can use alpha channel, load the image, and put noise over it.

Or generate noise with the pixels of the bitmap itelf?
- Maybe you can shuffle the array pixels somehow?
Title: Re: How to generate multiple images/save to files .. with random noise ?
Post by: yahoo000 on March 05, 2021, 02:31:04 am
But I don't get if you want to generate random noise over the image with alpha perhaps?
- If this is the case, you can use alpha channel, load the image, and put noise over it.

Or generate noise with the pixels of the bitmap itelf?
- Maybe you can shuffle the array pixels somehow?

But I don't get if you want to generate random noise over the image with alpha perhaps?
- If this is the case, you can use alpha channel, load the image, and put noise over it.

"yes exactly , over  the image" like in the below example

https://i.imgur.com/qgkUHtl.png

on the right you got noised original image but noised "strength=95"

I would like to generate let's say 300 images ... but with random noise strength "0.1 - 100" ..
Title: Re: How to generate multiple images/save to files .. with random noise ?
Post by: lainz on March 05, 2021, 02:45:08 am
That's easy too.

With the same noise function just provide the alpha channel in a parameter. Then blend your image with the noise and save it.

I'm not at the pc right now to write it. But you can do looking at the wiki examples maybe?
Title: Re: How to generate multiple images/save to files .. with random noise ?
Post by: yahoo000 on March 05, 2021, 03:01:54 am
That's easy too.

With the same noise function just provide the alpha channel in a parameter. Then blend your image with the noise and save it.

I'm not at the pc right now to write it. But you can do looking at the wiki examples maybe?

I cannot find it in wiki
can you show some example ?

thank you
Title: Re: How to generate multiple images/save to files .. with random noise ?
Post by: lainz on March 06, 2021, 05:08:01 pm
Code: Pascal  [Select][+][-]
1. procedure NoiseBW(Bitmap: TBGRABitmap; Alpha: byte);
2. var
3.   i: integer;
4.   p: PBGRAPixel;
5.   c: byte;
6. begin
7.   p := Bitmap.Data;
8.
9.   for i := Bitmap.NBPixels - 1 downto 0 do
10.   begin
11.     c := Random(2);
12.     p^.red := c + 255;
13.     p^.green := c + 255;
14.     p^.blue := c + 255;
15.     p^.alpha := Alpha;
16.     Inc(p);
17.   end;
18. end;
19.
20. {\$R *.lfm}
21.
22. { TForm1 }
23.
24. procedure TForm1.Button1Click(Sender: TObject);
25. var
26.   i: integer;
27.   bmp, bmpNoise, bmpComposite: TBGRABitmap;
28. begin
29.   bmp := TBGRABitmap.Create('image1.jpg');
30.   bmpNoise := TBGRABitmap.Create(bmp.Width, bmp.Height);
31.   bmpComposite := TBGRABitmap.Create(bmp.Width, bmp.Height);
32.   for i:=1 to 10 do
33.   begin
34.     bmpNoise.FillTransparent();
35.     NoiseBW(bmpNoise, Random(256));
36.     bmpComposite.PutImage(0, 0, bmp, dmSet);
37.     bmpComposite.PutImage(0, 0, bmpNoise, dmDrawWithTransparency);
38.     bmpComposite.SaveToFile('image1_random' + i.ToString() + '.jpg');
39.   end;
40.   bmpComposite.Free;
41.   bmpNoise.Free;
42.   bmp.Free;
43. end;
Title: Re: How to generate multiple images/save to files .. with random noise ?
Post by: yahoo000 on March 06, 2021, 05:28:20 pm
works great !!! thanks