simultaneous data acquisition & webcam video

[elixirnova]

I am still relatively new to Labview. I only have student edition of the software and a USB 6009 DAQ and do not have money to purchase any expensive software unfortunately.

I would like to acquire data from my load cell and Shaft encoder (which is working fine as is) as well as simultaneously record video to be paired with the data. The goal is to simultaneously record an athletes force output and sync it with hopefully 30fps decent quality video. Likewize record the shaft encoder's output and sync it with 30fps video. Is there any way to do this cheap? If not is there any way to do this at all even with expensive software?

The other option is I could just acquire the data and trigger video recording at the same time. It would be ok if I have a separate video file and data file for review, the most important thing would be to start and stop data and video recording simultaneously. This seems like my best bet... So is there an inexpensive method to use Labview and a cheap (~$100 range) webcam or video cam to be able to simultaneously start acquisition of data in labview and record a video. The webcams I am interested in right now are Logitech's HD Pro webcam C910 and Webcam pro 9000.

The only thing I have come up with thus far is to just have a front panel button to start data acquisition and then go over and click the record button on my webcam software and do the reverse to stop...

Not sure if it is important but I am running Windows 7 which might be problematic...

Thanks for any ideas,

William Broch

[elixirnova]

This AD Instruments article epicts exactly what I want to accomplish http://www.adinstruments.com/news/241108/Top-Swimming-Coaches-use-PowerLab-and-Video-Capture-for-Tec...

[CLSmith]

Elixirnova,

You have an interesting application.  There a couple of routes you could try out.  If the applications that control your webcams are ActiveX/.NET compliant, then you could programmatically control your acquisition software using LabVIEW.  Alternatively, you could purchase the Vision Acquisition Software which you may be qualified for a discount for if you are a university student.  If so, try calling our sales department for more information.  I did find an old free webcam library below that could be compatible. 

If you are able to programmatically control your acquisition then you could save the video file and then play it back with your data in LabVIEW using an embedded Windows Media Player control.  Depending on the webcam drivers (find driver documentation for your chosen webcam), you may also be able to call into the webcam driver dll using a Call Library Function node in order to start/stop acquisition.

LabVIEW Webcam Library « mindtrove

http://mindtrove.info/software/labview-webcam-library/

Best,

Chris LS

[elixirnova]

Thanks, I figured my cheapest option was the activeX or DLL method based on other discussion posts. I am a student at a university of missouri in Rolla, MO. The reason I am trying this all out is because we received a student package for our mechanical engineering classes so that discount sounds intriguing, but I'll try and post back when I get time to further explore my options. It seems like another option I have is to code everything in c/c++ but it sounds like labview can control everything I would need for standard webcams.

The big deal with this project is to keep it inexpensive so I'll have to look around and find the right webcam or camera system that I could utilize.

Although you didn't directly address the ability of labview to syncronize the video/data acquisition I am guessing you are saying that should not be a problem. It sounds like I can simultaneously start or stop the video via activeX or a DLL and start or stop the data acqusition together.

[elixirnova]

Well so far I have messed with IMAQ for USB (free) and a Vision evaluation. I am able to acquire and save to an AVI at around 12-15fps and I am display (no saving to AVI) at around 22fps which is what direct show is putting into IMAQ. This is a generic laptop imbeded "usb" webcam.

I am considering buying the new Logitech HD webcam (USB) to try with it since Logitech seems to have good ActiveX support as well.

I have not had much time to work on the project lately... but I'd like to improve the frame rate during acquisition/saving external AVI to well beyond 12-15fps. It would be nice to be closer to 25-30fps which is the camera I'm looking at's maximum rated frame rate.

So I figure the best way to write the software to accomplish this is to just save the video and force/velocity data from my USB 6009 DAQ to memory and then after acquisition is completed (about 20-30seconds) save the data to a an AVI file and then playback the data/video simultaneously in Labview for visual analysis. Any thoughts on whether this would be better done with IMAQ or an ActiveX control? I would be capturing a total of about 900frames max (30fps @ 30sec). I realize max frame rate would be limited by directshow with this method, but is there a way I could get the software's buffer larger than one frame at a time or possibly even buffer the entire video and save the data/clip afterwords?

Thanks for any help with this. I havn't ventured into any ActiveX control, but if anyone thinks it would be better for my application I will give it a go.