Draw Flattened Pixmap Issue

[kevindid]

I recently upgraded to LabView 8.20.  The VI I have takes an array of 8 bit data creates a pixmap (picture) and replaces any value between 2 values with a color.  It keeps the original values if criteria is not met and shows the original pixels as grayscale, R=G=B.  I read an array of values from a file.  This VI worked perfectly in version 7.1 now it only works if the thresholds I set are between certain values, meaning it will look OK for some settings and then after changing them it will blur on new settings.

Is there an issue with taking array data and creating a pixmap in version 8.20?

It is late, I hope this makes sense.

I have attached a VI that shows problem.  Read Data2.  It is a 20 x 320 array of values less than 255.

[Rudi_N]

kevin:

I was not able to find the array "data2" you referred in your last post. Please provide me with more information.

Regards,

Rudi N.

[altenbach]

Sorry, Your attached VI does not make much sense with respect to the problem you are describing. I cannot see any code that checks for range.

In any case, you should leave out the interleave operation entirely and display the image as paletted U8 image. All you need to do is give it a grescale color table. To color a certain range of values, simply operate on the color table directly, not on the image data.

Can you instead attach the LabVIEW 7.1 version that you claim works correctly? 🙂 Thanks!

Message Edited by altenbach on 01-12-2007 11:00 PM

[kevindid]

I originally tried to attach the VI and the data file that it reads and neither were uploaded.  Then I converted array read to an array constant with the values already embedded.  This VI I have attach has the threshold sliders on it.  I took them out in previous submittal since I found that even with out the thresholding piece the pictures were blurred.

Anyway, what I find is if you leave the top slider at 100 and slide the low one up above around 80 the picture is blurred, not the square pixel look that you get if the lower slider is at 50 or so.  This used to work OK on LV7.1.

Thank you for your suggestions,  I will investigate them today.

[altenbach]

OK, here's a quick draft how I would do it, operating exclusively on the color ramp. Basically, draw the greyscale image as U8, create a color ramp from 0..max (black..white), then replace elements of the color ramp according to the selected range. Seems much simpler than doing math on the big image array.

[altenbach]

Hoever, I DO see what you mean. LabVIEW 8.20 seems to add some bilinear interpolation (?) to zoomed images under certain (but not all) conditions. Here's a comparison.

I am not sure how to disable this "feature". 😉

Message Edited by altenbach on 01-15-2007 10:44 AM

Message Edited by altenbach on 01-15-2007 10:45 AM

[Justin D]

I'm going to look into this and see if I can determine what changed between LabVIEW versions.  I will let you know what I find.

-Justin

[Justin D]

Hi kevindid,

Could you please email support@ni.com and create a service request for this issue?  Mention my name and it should come to me.  This will help us track this issue a little better.  I can also communicate directly with you this way.

Regards,
Justin D

[Justin D]

This was reported to R&D (# CAR 4658JVCR) for further investigation.