Slow Framerates, Qimaging Firewire Camera

[blitzcraig]

I am acquiring from a Qimaging Retiga1300, firewire camera. It is not DCAM supported, so Qimaging has written their own LabView DLL to interface the camera. I use thier provided VIs to setup, acquire and convert imaq image to a picture format. I am getting a framerate of around 7fps when I am not displaying (just reading an image into the imaq buffer), and about 5-6fps when updating each image to the screen. When I change my binning down (resolution increase), I seem to get slower framerates. The camera is specified for 15fps minimum. I am using minimal and proper code (10ms delay in while loops, etc). The computer is a 533Mhz Celeron, 312Mb, VIA chipset MB, and the camera is connected thru a PCI IEEE-1394 card. I am hoping this development computer is just too slow, my app will be deployed on new mobile server. What are typical framerates LabView can handle for a 1080x1390, 12bit image over firewire?

[Lorne H.]

blitzcraig,

Tough questions today (I just responded to another question you posted).

Well... the correct answer depends on how fast your new computer will be.  LabVIEW does not have a speed limit (in other words, if you get a faster computer, LabVIEW will run faster).

So, you have two bottlenecks here, your computer and the firewire port.

Firewire can handle a maximum of 400 MBits/s which equates to around 22 fps for a 1080x1390 12bit camera.  It sounds like your camera is speced to definitely handle 15 fps, but it might get a little higher (I doubt it can reach the 22 fps, but maybe).

So, if your computer is fast enough, you can definitely get 15 fps.

My computer is a 3.19 GHz Optiplex GX280 with 1.49 GigBytes of RAM running WinXP SP2.  I have a Sony DFW-VL500 color Firewire camera attached to my machine.  Running the camera at 640x480 and 32bit color I can achieve an average frame rate of 34 fps.  That is 334 MBits/s, which is 60 MBits/s faster than your camera would need to obtain 15 fps at 1080x1390 and 12bits.

And with some fuzzy (extremely fuzzy) math we can approximate how fast your computer needs to be to achieve 15 fps.  You are currently getting 5-6fps with a 533Mhz Celeron and 312 MBytes of RAM, you should get close by tripling your computer power.  Realize that the 3rd party dll you are using to interface with yoru camera might add additional drag to your computer.

Have a Merry Christmas,
Lorne Hengst
Application Engineer
National Instruments

[blitzcraig]

thanks for the reply.  The new computer is a 1.2GHz Pentium M with 1gig of RAM.  It has a dedicated firewire port (on the MB) so it shouldn't be running on my PCI bus anymore.  Will post the resulting framerate when I hook it up.

[McFly]

I am getting a framerate of around 7fps when I am not displaying (just reading an image into the imaq buffer), and about 5-6fps when updating each image to the screen

The 7fps when displaying and 5-6fps when updating is a sign that your computer (or graphic card) is a bottleneck in the system. You may dexecute a test to "measure" the capability of your graphic card: acquire the image, display it and measure the framerate for the 2 different situations:
- minimize or move the window displaying the image so as it does not appear anymore on the screen
- normal situation when you can visualise the image being acquired

If the framerate is quite different in the 2 situations, it is a strong sign that the graphic card has problem to breathe correctly!

Loranger