Correcting fish eye lens distortion

[Ghost]

I have a number of highly distorted images that I need to correct. The problem is that I can not get the LabVIEW image calibration VI’s to give me a satisfactory result. I was wondering if anyone could provide some assistance. I have enclosed the VI I am using (part of a larger program) as well as my calibration image and a result from a 3^rd party program that achieves a much larger field of view than I can get from LabVIEW, but needs further calibration once it is ‘unwrapped’.

I would really like to get LabVIEW to do this so it can be part of one large project rather than having to use another program in the middle of my calculations.

[Aaron B.]

Hello,

You may want to take a look at some of the example programs that ship with Vision. They can be found in the example finder (Help » Find Examples...) under Vision » 2.Functions » Calibration. Another very useful tool is the Vision Assistant. Using property pages, you can manually set up and tweak your processing sequence. Then, when you are satisfied with the results, you can convert the VA script into a LabVIEW VI by selecting "Tools » Create LabVIEW VI"

Regards

Aaron B.
National Instruments

[Ghost]

Hi,

Thanks for the post. Unfortunately I am in the evaluation phase of IMAQ and do not have access to Vision Assistant.

I did look at the examples and copied parts of the nonlinear calibration example to do the lens correction. The problem is that in the example the calibration just works, there is no setting of extra parameters, or even an indication as to whether such settings exist. I have experimented with different shaped ROI’s but to no avail, the results that I get are far inferior to those of the other software.

Does anyone know if there are additional settings for the lens calibration VI’s?

Thanks.

[BruceAmmons]

I have done a lot of work with correcting image distortion.  If you are willing to spend a little money, I could put together some nice tools for calibrating your image and correcting other images.  It would include an interactive grid calibration procedure where you can manually correct the grid positions.  It wouldn't be quite as fast as the NI versions, but it would provide a lot more interaction and adjustment capabilities.  I think the final result would be better than the 3rd party correction you posted.

If you are interested, contact me.

Thanks,

Bruce

[Ghost]

I will consider your offer however what I really want is a complete solution for my entire application, of which this is only a small part, and any time I need to switch programs decreases the ability to automate the procedure. If it cannot be done as a single package then it is not likely to be worth getting the IMAQ toolkit.

Since it appears that the built-in functions in IMAQ are not adequate I will invest in a better camera/lens combination (one with less distortion) and just use other, more flexible, software that I already have access to.

[Ben]

"I will consider your offer..."

For what it is worth I would like to confirm that Bruce is the most active contributor to the NI Vision forums as well as Info-LabVIEW. I have concidered him one of the worlds top LV developers and vision experts. He was also one of the first 9 LabVIEW Champions (see link below)

http://www.ni.com/devzone/lvzone/member_directory.htm

Feel fre to contact me at

bar@dsautomation.com

If you would further like to confirm anything that I have said.

Ben

[Ben]

And one more thing...

The only reason I have been watching this question was I wanted to hear what Bruce had to say!

And NO, I do not work for Bruce and technically speaking he is one of my competitors !

Ben

[RManion]

Agreed!

I know that those of us who work with Vision on a daily basis have always appreciated Bruce's input!

Robert Manion

Applications Engineering

National Instruments

[BruceAmmons]

It is always nice to see support from the LV community!

Perhaps I forgot to mention that all my image correction tools are 100% LabVIEW.  Technically, IMAQ isn't even required, but it can make the job a lot easier.

Bruce

[Ghost]

I will see what sort of distortions I get from my new camera (provided I get my grant) and I will contact you if my solution is not sufficient.

Thanks again for your offer.