Lens Distorition Calibration

[JeroenM]

Hello,

I'm am new on the LAVA forum, i'm a student form Fontys Mechatronic's in the Netherlands. We have started a project to build a robot for the fieldrobot competition (www.fieldrobot.com).

I'm am using Labview 8.6 with Vision, we have a omni-directional mirror to create a bigger view but we have alot of lens distorition. So we wanted to calibrate it with labview Vision assistant but the result isn't useful and it takes 3,6 seconds to calibrate which is way to long. (see attachments for the test photo's).

What can we do to speed up and get a better result in labview?

Greetz Jeroen

(sorry for the bad english)

[Neville D]

I'm not sure what your issue is.. you can save the calibration and reuse it later, you don't have to calibrate every time. You can also apply calibrations to images with a Region of Interest marked out. In that case, Vision is smart enough to calibrate only the ROI part of the image speeding things up.

so look for some feature of interest, mark it with a ROI rectangle and then apply whatever processing you need, and you will get results in calibrated real-world coordinates.

Neville.

[JeroenM]

I already mask everything that is not needed for the analysis, the main problem is that the calibration is not what I want the round picture must be calibrated to a square where it looks like it is a normal photo without distorition.

[Neville D]

QUOTE (JeroenM @ Mar 19 2009, 01:46 PM)

I already mask everything that is not needed for the analysis, the main problem is that the calibration is not what I want the round picture must be calibrated to a square where it looks like it is a normal photo without distorition. The dots in de the middle of de calibrated image are not round like the rest of de dots.

You mean you want the image dewarped? I don't think there are any built-in routines to dewarp an image. You will have to write your own. The calibration functions are meant to extract out measurements in real-world units, so your measurements will be correct, but the picture won't "look" flat.

We have done this in the past; dewarping is quite processor intensive, and for a machine vision app its only eye-candy.. it looks great, but serves no measurement purpose. You can use calibration routines for measurement.

Read the first few chapters of the NI Vision Concepts Manual for more info.

Neville.