Camera lens distortion correction

kbarni · December 11, 2007

Hello,

Here is a simple plugin to correct the barrel or pincushion distortions in digital photos.

(More information about these distortions in wikipedia article)

You can download the plugin here:

To use it simply unzip it to c:/Program Files/Paint.NET/Effects/, the plugin is in Filters->Photo->Distortion

Here is an example of the plugin usage. On the first photo you can see the effect of the lens distortion (I traced it with dotted red line), which was eliminated in the second image using the plugin:

This effect is even stronger with macro shots, cheaper lenses on compact cameras and ultra-wide (fisheye) lenses.

I wrote the plugin using Codelabs, if there is someone who would like to implement it in C# (in order to give a nice interface or to optimize it), i can post the source code.

Edited June 20, 2020 by toe_head2001
Fixed attachment

Fisherman's Friend · December 11, 2007

1.) You should consider to add example pics. They make it easier to speak about it. And people want to see what they will get.

2.) You have done it with codelab? How about providing the source code? I would be interested.

MadJik · December 11, 2007

Yes, sure I may help you (if you want me to)...

I already think about the IndirectUI features:

...Choose the center X,Y Offset,

...Keep background (yes/no, instead transparent)

...X,Y separated factors

...Limits +/- 500 (instead 50) : ok perhaps it's crazy, but just for the fun of distortion!

Like I did here:

viewtopic.php?f=5&t=21525

(you could use this source as a template by your own...)

Let me(us) know...

Rick Brewster · December 12, 2007

Screenshots please!

pyrochild · December 12, 2007

Is there any reason why the left and right edges of the image are left intact?

Fisherman's Friend · December 12, 2007

Screenshots please!

I made some. @Pyro: This issue is occuring when I use it, too.

Edit: Please note: I forgot to change the language to English. To prevent confusion, "Abbrechen" is not a weird plugin-related button, but means just "Cancel". :wink:

And please forgive me the bad quality of the pictures, but I want them to be suitable for all bandwiths.

kbarni · December 13, 2007

Good people, here's the code for CodeLabs! Have fun playing with it, I hope you'll make it even cooler!

int Amount1=-20;   //[-50,50] Amount per thousand(°/oo)

float [] rd = null;
int Achange=0;	//To verify if there is a slider change

void Render(Surface dst, Surface src, Rectangle rect)
{ 
   float Percent= (float)(Amount1 / 500.0f);  // Distortion percent

   PdnRegion selectionRegion = EnvironmentParameters.GetSelection(src.Bounds);

   Rectangle selection = this.EnvironmentParameters.GetSelection(src.Bounds).GetBoundsInt();

   int w,h,x0,y0,w2,h2,raymax;
   float xd,yd,rdcur,ru;
   w = selection.Right - selection.Left;
   h = selection.Bottom - selection.Top;
   x0=selection.Bottom;y0=selection.Right;
   h2=h/2;w2=w/2;
   raymax=(int)Math.Sqrt(h2*h2+w2*w2)+1;
   if(rd == null){ //first run->alloc and init
       rd = new float[raymax];
       Init(raymax,Percent,w,h);
   }else if(Achange!=Amount1){  //slider change->reinit
       Achange=Amount1;
       Init(raymax,Percent,w,h);
   }
   for(int y = rect.Top; y < rect.Bottom; y++){
       for (int x = rect.Left+1; x < rect.Right/2+1; x++){	//BUG: if it goes from rect.Left it gives an exception
           ru=(float)Math.Sqrt((float)((w2-x)*(w2-x)+(h2-y)*(h2-y)));
           rdcur=rd[(int)ru]*(1-ru+(float)Math.Floor(ru)) +  rd[(int)ru+1]*(ru-(float)Math.Floor(ru));
           rdcur/=ru;
           xd=(w2-x)*rdcur;yd=(h2-y)*rdcur;
    dst[x,y] = src.GetBilinearSample(w2-xd,h2-yd);
    dst[w-x,y] = src.GetBilinearSample(w2+xd,h2-yd);
       }	//idea of optimisation: the function is symmetrical horizontally and vertically,
       	//so at the same moment (x,y),(w-x,y),(x,h-y),(w-x,h-y) can be calculated
   } 
}
void Init(int raymax, float percent, int w, int h)
{		//We precalculate the distortion function in rd
   	double k,r,inc,ru1,ru0,m;
int l;
// *** Calculate K *** (k is the distortion constant based on the distortion %)
double yd1,yd2,rd2,alfa;
yd1=h/2;
yd2=yd1*(1-percent);
alfa=Math.Atan2(h,w);
rd2=yd2/Math.Sin(alfa);
k=(yd1-yd2)/(rd2*rd2*yd2-yd1*yd1*yd1);


   	r=0;
inc=0.1;
l=1;rd[0]=0;
while(l		ru0=r+r*r*r*k;
	r+=0.1;
	ru1=r+r*r*r*k;
	if(Math.Floor(ru0)!=Math.Floor(ru1)){
		m=(ru1-ru0)/inc;
		rd[l]=(float)(r-(ru1-Math.Floor(ru1))/m);
		l++;
	}
}
}

kbarni · December 13, 2007

And sorry I didn't post any screenshots, here's mine, a real example with lens distortion:

On the original I marked the distorted edgees with red dotted line. There are lenses with even stronger distortions (especially the wide angle zoom lenses). I hope you find this plugin usefull.

Fisherman's Friend · December 13, 2007

Thanks!

MadJik · December 13, 2007

Ok...
This is the code with the new IndirectUI

Added:
X,Y offset (strange effect)
Quality level

Changed:
Bug left/right seams solved
Range -/+ 500

Source : CameraLens.zip

Updated dll:CameraLens.zip

kbarni · December 13, 2007

I updated the original plugin, still using my codelabs version. You can download it in the original post!

This fixes just the nasty edge bug, there is no other change.

Thanks for the quick modification, MadJik, I think I'll modify your version too (when i'll have time)!

Rick Brewster · December 14, 2007

There are some major rendering goof-ups if you move the center/offset around. It looks like the effect is not writing to every pixel in DstArgs, and so they just retain their old values.

R3VENGE · January 1, 2008

this will help making tv screens for my ut2k4 maps. im new to plugins but i have loads within one night lol.

Red ochre · February 27, 2016

I doubt kbarni is still visiting the forum, so not too much point in posting this?. (I was using it within a selection).

Shame, as it is a useful effect. Thanks for posting the code, I may try to squash some bugs :bug: at some point.

File: C:\Program Files\NEWpdn\Effects\kb_lens.dll
Effect Name: PaintDotNet.Effects.UserScript
Full error message: PaintDotNet.WorkerThreadException: Worker thread threw an exception ---> System.IndexOutOfRangeException: Index was outside the bounds of the array.

Herbii · June 20, 2020

Hi there! Trying to download this plugin but nothing works. It doesn't even download as a .zip?

toe_head2001 · June 20, 2020

The file is a ZIP file, but was simply missing the .ZIP extension. I've fixed the attachment to resolve that.

Haoto · August 12

The plugin is not showing up. I can't find it in the Distortion section.

I'm still on version 4.3.12; this could be the reason.

Pixey · August 12

26 minutes ago, Haoto said:

I'm still on version 4.3.12; this could be the reason.

Absolutely! You must update the latest version in order for the Plugins to work correctly.

Haoto · August 12

22 minutes ago, Pixey said:

Absolutely! You must update the latest version in order for the Plugins to work correctly.

Is there a way for me to download the older version of this plugin?

The reason I'm not using the latest version of Paint.NET is because there are other plugins that won't work on the newer version. Also, some of BoltBait's plugins had changes I didn't like, so I stuck with the older version.

Edited August 12 by Haoto

Pixey · August 12

6 minutes ago, Haoto said:

Is there a way for me to download the older version of this plugin?

No, one can't, sorry. The best way is to update to the latest version of paint.net. I'm afraid we can't give solutions, or help, with older versions.

If you are having problems with newer Plugins, one has to 'bite the bullet' and learn how to use the newer Plugins

If you have a particular problem with one of the newer ones, you can post an image of what you ae trying to accomplish and people on here, as well as the Plugin author, should be able to help you to get to your desired result.

toe_head2001 · August 12

This plugin is absolutely ancient, and does not require the latest version of Paint.NET.

Your problem lies elsewhere.

You should use the latest version of Paint.NET anyways though.

Haoto · August 12

@toe_head2001 Is there another plugin that's up-to-date but does the same thing as this one?

I'm still hesitant on using the new version of Paint.NET because the changes made to the plugins will ruin my consistency...

All I wanted was text alignment, especially when there's multiple paragraphs.

Edited August 12 by Haoto

Red ochre · August 12

1 hour ago, Haoto said:

I can't find it in the Distortion section.

It's under Effects/Photo not Distortion.
Still working in 5.08 🙂

Pixey · August 12

@Haoto I tested it in both 4.3.12 and 5.0.9 an it is still working in both.

Camera lens distortion correction

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