topic Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages in Machine Vision

Image acquisition with 3 USB cameras causing too much memory/cpu usages

hart — Wed, 27 Aug 2008 03:28:05 GMT

Dear experts,

I am trying to capture images with 3 USB cameras located at 3 different positions. I have to initialize each USB cameras using enumerate camera vi when switching among cameras. I realize that by doing that method causing too much memory/cpu usages and might cause CPU to hang up. If I stop the program, the memory/cpu meter are going down.

Do you know how to minimize this problems.

Thanks,

hart

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

K_Bull — Wed, 27 Aug 2008 10:04:49 GMT

Hi,

Do you mind posting your VI to show me how you are doing this? I will see what I can do for you.

Regards,

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

muks — Wed, 27 Aug 2008 10:33:21 GMT

Hi hart,

IS it a parallel capture that u r attempting?Is any one camera waiting for a trigger?As kabul mentioned posing your vi or a screen shot will defenitely help

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

wbadry — Wed, 27 Aug 2008 11:10:30 GMT

hi hart,

USB cameras consumed tremendous amount of memory. New USB 2.0 cameras has much more bandwidth to consume rather than 1.0 and 1.1 counterparts which made it less CPU power consumer. Here is a tip, if you want to use mutiple cheap cameras with LABVIEW, you can buy a cheap analog camera (30 $) and a TV tuner (about 20 $ ). LABVIEW USB driver deals with any directshow cameras. these include video streaming from TV tuners.

It soved a problem with students of mine once, and we got rid of memory leak.

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

pallen — Wed, 27 Aug 2008 15:27:21 GMT

Here is a tip, if you want to use mutiple cheap cameras with LABVIEW, you can buy a cheap analog camera (30 $) and a TV tuner (about 20 $ ). LABVIEW USB driver deals with any directshow cameras. these include video streaming from TV tuners.

So, you connect multiple analog cameras to a single TV Tuner card and then use the directshow drivers to pull in a single stream from the tuner card?

This sounds interesting.

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

wbadry — Wed, 27 Aug 2008 16:50:42 GMT

You can buy TV tuners with multiple inputs, even old ones has:

One port for A/V in
One Port for Composite Video in

the third can then be utilized using USB port (only one USB camera is to be hooked up and thus the CPU load will vanish for good).

It is worthy to say that TV tuner is better to be PCI (we don't want to return back to USB latency 🙂 )

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

Michelle_N — Tue, 01 Apr 2025 14:50:21 GMT

hart,

Thank you for using our forums! The IMAQ for USB driver has a known memory leak. Please read the known issues section on that link. But it all depends on how you are calling the cameras. Please post you code.

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

hart — Thu, 28 Aug 2008 01:48:35 GMT

Dear Kabul M,

I would like to post the vi, but I made a lot of sub vi and are located in different folder, do you know how to merge all the vi? So that none of the sub vi missing when sending to you.

Thanks.

Regards,

hart

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

muks — Thu, 28 Aug 2008 11:17:38 GMT

Hi hart,

You can post the vi after converting it into llbs.

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

muks — Thu, 28 Aug 2008 11:22:47 GMT

Click save as and choose new llb.

Message Edited by muks on 08-28-2008 06:22 AM

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

hart — Sat, 06 Sep 2008 01:03:24 GMT

Dear Kabul M,

Sorry for late reply. Herewith I attached my code for your evaluation

thanks,

hart

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

C_L_O_U_D — Wed, 17 Sep 2008 23:27:54 GMT

Hi Hart

Now I'm curious. What exactly your VI does? What is it for?

Incredible: I am working on a project just like yours, but in mine I have to process the images with Vision Express. Basically it snap one pic from the first usb camera and process it. If it 'capture' something different (human movement) in the place, It have to start recording video into a file. If don't, go to the second usb camera and so on.

I'm a beginner in labview and havin' a lot of troubles dealing with it.

If I can get any kind of help, I will be grateful. I´ve tryed to open your llb but it shows several warnings (subVI that is missing).

Tks

(PS: Sorry 'bout my english. It isn't very good.)

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

hart — Thu, 25 Sep 2008 02:09:58 GMT

Dear Michelle, Here I had attached my code in LLB format. The main program is "Mecron_2007(USB-1024x768).vi".

I use Labview 7.1. Could you please evaluate/check my code for any incorrect programming that could cause the memory leak problem?

thank you very much.

regards,

hart

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

hart — Wed, 08 Oct 2008 05:31:32 GMT

Dear Michelle,

I've posted my code (.vi) which was programmed by Labview ver7.1. Have you check any problems with my cod, so that I can solve the problem.

Thank you for your kind advice.

Regards,

hart

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

hart — Wed, 15 Oct 2008 01:40:20 GMT

Dear Muks,

I've already posted my code last 2 weeks, seems like nobody reply. So, has anyone checked my code? Anyway, I would like to thanks for any advice given. Do you know what is actually problem with my code?

Regards,

hart

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

KrisnaWisnu — Tue, 21 Oct 2008 08:36:43 GMT

Hi Hart,

Did you solve the problems?

If not, please allow me to ask few questions:

1. Is it necessary for you to perform continous acquisition (Grab) in three cameras at once?

2. Have you tried to use TV Tuner as suggested in the early post? it sounds an interesting working around.

Currently, from the information that you described, I am suspecting the cause of the problem is because the continous acquisition from three cameras which overload the memory buffer. Looking forward for your reply.

Sincerely,

Krisna Wisnu

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

Klattan — Mon, 22 Jun 2009 12:51:45 GMT

Dear hart,

I am also trying to capture images with 2 USB cameras (HP web camera) located at 2 different positions.

But i could not connect both at a time. Can you share your experience?

Rgds,

Klattan

Re: Image acquisition with 3 USB cameras causing too much memory/cpu usages

hart — Tue, 23 Jun 2009 00:30:56 GMT

NI IMAQ USB does not support simultenous image capturing, that is why you couldn't connect 2 cameras at a same time. Anyway you can initialize/connect a camera one at a time.

Thank you,

Hart