rotate image

[willem]

Hi

I have a narrow but very long image (2047 x 16,000) which I wish to rotate by 90 deg so I make better use of the display screen. Using 'IMAQ rotate' this takes on average 2.5 sec. I then tried 'image_to_array, transpose_array, array_to_image, but this took even longer 3.2 sec. As this is only a transpose operation and and no re-calculation of pixels is required why does it take this long ?

Is there some other way to speed it up.

Willem

PS (Using LabView 7.1 and Vision 7.1)

[TiTou]

Hi Willem,

Could you try with this vi...
I don't remember exactly where I found it, but it was on labVIEW Zone, maybe it can be of interest for you..

If so, get inspired !

[Ben]

Hi TiTou,

This looks a lot like an example posted by Christian in the "Picture Control" thread.

http://forums.ni.com/ni/board/message?board.id=BreakPoint&message.id=14&jump=true

Does this look familiar?

Ben

[TiTou]

Yep Ben, this is certainly correct... I used it as a source of inspiration a couple of month ago and couldn't remember the thread it was coming from ; so many thanks to Christian.

I hope nobody minds if I use it... 'cause I like it !

[Ben]

I suggest you throw a couple of extra stars on Christian's original post just to be safe.

And thank YOU for giving me another excuse to plug the "Picture Control" thread.

Ben

Message Edited by Ben on 01-11-2006 08:21 AM

[TiTou]

I wish I could... but I already did give him a 5, when I first saw the vi...

[Ben]

"I wish I could... but I already did give him a 5, when I first saw the vi...  "

Pay in advance?

Great idea!

Ben

[TiTou]

Am I missing the point ?
I meant I gave him stars because I liked his VI the first time I saw it a couple of months ago.

There's no pay in advance, is there ? Or do you you mean I should pay in advance for the next time I'll use one of his VI ?
Well, great idea.. how can proceed to do so ?

have fun and a good day

[willem]

TiTou/Ben

Never mind the stars, you seem to rather have missed the point of this question. I have a very large image (2047 X16,000), which I want to rotate by 90 deg. When I try to make the image larger in your vi, it just grinds to a halt well before it reaches the size I want to rotate.

Any other ideas?

Thanks

Willem

[Ben]

Hi willem,

If you use that example "out of the box" for an image that large, it looks like you will need as much as a Gig or more to handle an image that is 16K X 16K.

Even if you have that much memory to play with LV may have trouble allocating contiguous buffers that large.

You will probably have to "divide and conquer" to win this battle.

I suspect if you grab 2047 X 2047 sections sections, and then rotate each setion (using the method Christian illustrated) you should be able to put the image back together again.

Does that help?

Ben

BTW: The reference to stars is part of a running joke that the "Gold bars" (non-NI) contributors work for stars (not penuts).