When I read images from TDM reading speed falls down, why?

[Evca]

I'm using TDM storage to save images, every image is saved in its own channel. When I read the images, reading speed slows. And the same probleme is when I save the images. But I need to write (read) images as fast as possible and with the same time period for all the time.

Can you help me?

Thank you Eva

[Rudi_N]

Eva:

I would need more information to further assist you. How many images are you reading/writting ? Is the operation faster if you use fewer images or is it slow all the time?

Rudi N.
Applications Engineer

[Evca]

Now I have 200 - 300 images, but in future is posible it will be thousands. The main problam is that at the begining it reads (writes) quite quickly, but with every new read image is it slower. The time, which is necessery to read (write) new image is longer, so there isn't constant period between the images. If I use fewer (50) images, the period also increases.

I hope its enough information, so you ca help me now.

Thanks Eva

[Charlie S.]

Hi Eva,

The native TDM Storage VI's are not necessarily the best solution for every application -- in particular, when you need to stream large amounts of data and time is critical. I would suggest instead that you use the TDM Header Writer VI's:

Introduction to the LabVIEW TDM Header Writer VIs

http://zone.ni.com/devzone/conceptd.nsf/webmain/117CB3D512ED96928625707B004DC4E9

The idea is that you stream your data to disk in a binary format and then add the TDM header (channel) channel information later. We are always looking for ways to improve our storage VI's. If you have any ideas, you are certainly welcome to submit them:

http://sine.ni.com/apps/utf8/nicc.call_me

Hope this helps!