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Author Topic: question about using the chessboard from the Agisoft lens software.  (Read 957 times)

Jumboo

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Hi,
I am new to calibration.
Now I have a question about using the chessboard from Agisoft lens.
I'm using Photoscan to make a 3D model for a object (such as a statue). And I want to use Agisoft lens for a percalibration.

I choose "Show Chessboard" and there is a big chessboard in the whole screen.
According to the manual I should take photos of the chessboard like the picture below.
But there is a problem. I use a prime Lens for taking photos. For the Photoscan process, all the parameters of camera should not be changed while taking photos. And I should use the same parameters to take photos of the chessboard. In this situation, the photos are badly out of focus because of the near distance between screen and camera.

My question is, can I play the focus to get the clear photo of chessboard? I'm using prime lens, I'm not sure it means the focal length also be fixed in this situation.

Can sombody help me?




The link of picture is:
https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=imgres&cd=&cad=rja&uact=8&ved=2ahUKEwi_78rKrYPdAhUKblAKHaeDBGQQjRx6BAgBEAU&url=https%3A%2F%2Fwww.researchgate.net%2Ffigure%2FThe-Chessboard-for-camera-calibration-in-laboratory-environment-Fig-5-The-sequence-of_fig3_322370374&psig=AOvVaw1ZvdPtEn4WbQLpQZnHUidQ&ust=1535119947141905
« Last Edit: August 23, 2018, 05:38:33 PM by Jumboo »

pbourke

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Re: question about using the chessboard from the Agisoft lens software.
« Reply #1 on: March 14, 2019, 03:53:02 AM »
This is an old question, but I'm interested in the answer also.
My feeling is no, the focus does not change the derived parameters. It would be kind of pointless if it did because typically one is going to focus differently for each shot of the actual subject anyway.
Certainly I focus on the chess board when doing a lens calibration.
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