How to generate multiple images/save to files .. with random noise ?
lazarus / 39-Graphics

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yahoo000 · 2021-03-05 00:00

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.

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lainz · 2021-03-05 01:04

Yes, using BGRABitmap is easy

Color noise:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
Noise(Bitmap: TBGRABitmap);var  i: integer;  p: PBGRAPixel;begin  p :=
Bitmap.Data;   for i := Bitmap.NBPixels - 1 downto 0 do  begin   
p^.red := Random(256);    p^.green := Random(256);    p^.blue :=
Random(256);    //p^.alpha := Random(256);    Inc(p);  end;end;
Black and white noise:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
NoiseBW(Bitmap: TBGRABitmap);var  i: integer;  p: PBGRAPixel;  c:
byte;begin  p := Bitmap.Data;   for i := Bitmap.NBPixels - 1 downto 0
do  begin    c := Random(2);    p^.red := c + 255;    p^.green := c +
255;    p^.blue := c + 255;    //p^.alpha := Random(256);    Inc(p); 
end;end;
Just do something like this:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i var  i:
integer;  bmp: TBGRABitmap;begin  bmp := TBGRABitmap.Create(640,480); 
for i:=1 to 300 do  begin    NoiseBW(bmp);   
bmp.SaveToFile('image1_random' + i.ToString() + '.jpg');  end; 
bmp.Free;end;
Edit: add to uses clause BGRABitmap, BGRABitmapTypes.

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lainz · 2021-03-05 01:08

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?

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yahoo000 · 2021-03-05 01:31

Quote from: lainz on March 05, 2021, 02:08:19 amBut 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" ..

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lainz · 2021-03-05 01:45

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?

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yahoo000 · 2021-03-05 02:01

Quote from: lainz on March 05, 2021, 02:45:08 amThat'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

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lainz · 2021-03-06 16:08

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
NoiseBW(Bitmap: TBGRABitmap; Alpha: byte);var  i: integer;  p:
PBGRAPixel;  c: byte;begin  p := Bitmap.Data;   for i :=
Bitmap.NBPixels - 1 downto 0 do  begin    c := Random(2);    p^.red :=
c + 255;    p^.green := c + 255;    p^.blue := c + 255;    p^.alpha :=
Alpha;    Inc(p);  end;end; {$R *.lfm} { TForm1 } procedure
TForm1.Button1Click(Sender: TObject);var  i: integer;  bmp, bmpNoise,
bmpComposite: TBGRABitmap;begin  bmp :=
TBGRABitmap.Create('image1.jpg');  bmpNoise :=
TBGRABitmap.Create(bmp.Width, bmp.Height);  bmpComposite :=
TBGRABitmap.Create(bmp.Width, bmp.Height);  for i:=1 to 10 do  begin 
 bmpNoise.FillTransparent();    NoiseBW(bmpNoise, Random(256));   
bmpComposite.PutImage(0, 0, bmp, dmSet);    bmpComposite.PutImage(0,
0, bmpNoise, dmDrawWithTransparency);   
bmpComposite.SaveToFile('image1_random' + i.ToString() + '.jpg'); 
end;  bmpComposite.Free;  bmpNoise.Free;  bmp.Free;end;

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yahoo000 · 2021-03-06 16:28

works great !!! thanks