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Author Topic: Strange Calibration Parameters, or okay?  (Read 2967 times)

anvi

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Strange Calibration Parameters, or okay?
« on: May 12, 2014, 11:28:29 PM »
Hey,

in the attached screenshots you can see our calibtration parameters.
It's a Panasonic GH3 with 12mm lense - I used a very big TV flat screen.

Why does the graph go down on after the top (Radial distortion)?
All graphs i've seen in tutorials/videos are going up like the right one...

Is this calibration okay?

Thank you!
Andreas

anvi

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Re: Strange Calibration Parameters, or okay?
« Reply #1 on: May 14, 2014, 11:23:10 AM »
I found the problem - The Focus must be on infinity, but not till the block of the lense!

gEEvEE

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Re: Strange Calibration Parameters, or okay?
« Reply #2 on: May 27, 2014, 06:03:14 PM »
Seems OK to me.

Radial distortion can have both positive (outward, away from the principal point) and negative (inward) values. Negative radial distortion is denoted as pincushion distortion (since an imaged square will appear to have its sides bow inward), while positive distortion is termed barrel distortion (because straight lines bow outward). Either positive or negative radial distortion may change with image height, and its amount is also affected by the magnification at which the lens is used. It can also occur that one lens system suffers from both negative and positive distortion, like your example.

Cheers, Geert

heema

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Re: Strange Calibration Parameters, or okay?
« Reply #3 on: September 09, 2014, 10:34:05 AM »
Hello,
thank you again for your effort. I now got the information that the values were computed with a program called "Bingo". Can that help me?
heema