I did it.... Fish Eye... Call Me Kinlan The Chuffed!!!

Paul Kinlan

It wasn’t too hard…. I did take a peak at the code behind the that Jason Waltman describes. I did this purely because the code I implemented seemed to match the pseduo code that was written but my results were not quite correct. I looked at the code, converted it to c# implemented it as a filter in the Tiger Image Processing Library (Tiger Imaging) for C# here and it worked pretty much the first time it was tan.

I understand a bit more about polar co-ordinates now as well :)

Basically we have are our normal Cartesian Co-ordinates (x,y) which are used on our screens as pixel locations ((0,0) is the top left, (10,10) is 10 pixels in from the top left etc). Polar co-ordinates are co-ordinates that are specified in Angles and units from the center of a Circle …. I think!

So a Polar Co-ordinate (angle = 45, radius = 20) would mean that the point we want is 45 degrees from North and 20 units out from the centre.

This is useful in the Fish Eye Effect which needs to work out what pixels will be in the fish eye region.

The Fish eye effect has two basic stages

  • Work out which pixel should be fish eyed
  • If a pixel needs to be fish eyed, work out where the pixel should be placed based on where it is in the fish eye’s view.
Hmm…. Don’t know if I made too much sense there, but I will comment the code a bit more and then post it as a link.

Paul Kinlan

Trying to make the web and developers better.

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