2d (image) (array) smoothing algorithm

[DonRoth]

Hello:

I am attaching images prior to and after applying a proprietary smoothing algorithm (not in LabVIEW).  I have tried to duplicate this smoothing using a variety of algorithms including up to10x spline interpolation as well as smoothing options available in Vision (low-pass filtering, local average, guassian, median filtering [after converting to 8-bit grayscale image]) but cannot come up with nearly as good of smoothing effect as that shown here as I always still see some pixelation.  Any ideas for high quality smoothing algorithms for 2d arrays (images) using LabVIEW?

Thanks,

Don

[altenbach]

please standby

Message Edited by altenbach on 07-09-2008 02:35 PM

[altenbach]

Don

Do you have the raw data?

The pixels are highly rectangular, so it would be important to have the raw data without the repeated pixels in the x direction. (sure, I could probly add some code to extract it, but why?)

Each image column is already quite smooth, so what you need to do is reduce the x dimensions to a set of unique slices and then interpolate to generate the new, smooth, rows at the present scale to end up with to square pixels again.

Here's a quick attempt using 2D circular comvolution with a Gaussian of 0.1% width in y and 3% width in x. I am sure once you can post the raw data, things will fall into place just fine.

Message Edited by altenbach on 07-09-2008 02:55 PM

[DonRoth]

Hello:

The third party program did have an option to export the file to .txt.  I then brought the file into excel and removed header information.  Subsequently, I attempted smoothing again in my LabVIEW program and am satisfied with 10x spline interpolation result.  It appears that there is a problem attempting the interpolation on the original .png file.  I don't know why.  When you did your smoothing that you posted, were you able to display the original .png file I had posted (test.png) in an intensity graph with proper color table?




Message Edited by DonRoth on 07-10-2008 08:56 AM

[ShotSimon]

altenbach,

Can I please see your code for doing this?  -SS

[DonRoth]

ps. I would also be interested to see that code from Christian.  Here is the implementation of 2d spline interpolation I am using. Can't guarantee it is the best but generally works well....Don



Message Edited by DonRoth on 07-10-2008 09:55 AM

[ShotSimon]

DonRoth,

Thanks for sharing.  Something in your code caught my interest, What is the Request Deallocation block doing?

I guess I just always assumed Labview was doing this behind the scene:)  Does this improve performance for you?  -SS 

[DonRoth]

Most likely, it is not needed for this code and can be removed.  I tend to put it in when large multi-dimensional array information has to be manipulated in memory just in case.

Sincerely,

Don

[DonRoth]

....Same subVI as above but cleaner front panel and with connections made....Don