How can I capture live video and still image by a DirectX compatible USB webcam using LabView ?

[Gem_Pasha]

Dear forum members
   I'd like to design a user interface which shows a live video and capture still images for it by a DirectX compatible USB webcam using LabView or NI Vision Toolkit, how can I do this ? and If this is possible How can I reach the webcam DirectX filter properties and set them using LabView ? I would be grateful to anyone Who lead me to the correct solution.

    Sincerely
    Cem DEMiRKIR

[Allison_S]

Cem Demirkir,

    Well a good place to start is to make sure you have all of the pieces.  First off, your camera will need to be DirectShow compliant, since it is DerectX it most likely is but it would be good to double check.  Next, you will need the IMAQ USB driver, so that our software can easily communicate with your camera.

    As far as getting a User Interface that shows video and still images, that can be done using the techniques in our example programs for LabVIEW (Help >> Find Examples...), if you have more questions about that let me know.  Also, I'm not quite sure what you mean by reaching the webcam's DirectX filter properties and setting them, if I could get more clarification we can look into that.  If you have more details on what you're trying to accomplish maybe we can figure out another way to do what you want.  Let me know if you have anymore questions!

-Allison S.

Applications engineering

[Gem_Pasha]

Dear Allison

    Thanks for your reply. I've allready installed IMAQ USB driver and I can run the some example and see the camera filter properties under IMAQ directory. I'd like to implement an interface for capturing two still images coming from two different camera at the same time and saving them two different image file. And also I'd like to implement camera calibration for one of the cameras. Is there any built-in camera calibration procedure in NI vision toolbox. For DirectShow camera filter properties I guess it is not possible to set its values programmatically, for example zoom & motion parameters for aligning camera view to capture some objects properly.

   Sincerely

   Cem DEMiRKIR

[Allison_S]

Cem,

    With our example programs you can acquire and save an image (IMAQ >> File Input and Output >> Snap and Save to File.vi) from one camera, if you double the VI's to create the image and the image task, you can easily have one program acquire and save for two cameras.

    I may need more information on what you mean by calibration.  Do you mean basic camera setup?  That can be done in Measurement and Automation Explorer by setting up the options within the IMAQ settings for each camera.  Or do you mean more complex calibration for special types of images?  The more description of what you mean, the better I will be able to help you get it done.  You mentioned zoom and motion parameters, what kind of motion?  Our vision drivers only control triggering the camera to acquire, then analyzing, processing and displaying the resulting image.

    If you have more details on exactly what you want to do, that would be great.  Let me know if you have more questions, thanks!

-Allison S.

Applications Engineering

[step1up]

I have a problem using a camera that output NTSC video signal (miniVID from LW Scientific) and a directx compatible usb capturing device (Kworld usb DVD maker). When I try to acquire a new image using NI vision assitante I get a message that the camera setting are not valid. however, the device is listed.

can any one help me with this problem.

thank you.

[Chris_VH]

step1up,

When you say the device is listed, where is it listed at?  Whatversion of Vision assistant do you have? Does the error popup when you select USB camera? Some of these answers will help us narrow down the problem.

[step1up]

I'm using Vision asstant version 8.6. The message appears after I select "Aquire Image (USB)". Under devices I see "USB 2860" whihc is the for the capture device I use. after I close the message, The acquire usb dialog is grayed out. therefore, I'm not able to change any settings on the capture device.

thanks

[Chris_VH]

step1up,

Can you verify that your device is DirectShow compliant? This isbasically the standard that needs to be met for our USB drivers to work.

[step1up]

I'm not sure if it is DirectShow compatible. but, that's what I assumed. Since it is DirectX compatible, it will most likely be DirectShow compatible.

I guess that is the problem I am experiencing. I went ahead and purchased a DirectShow compatible frame grabber device; I was told by the suplier that many of their costumers successfully used it with labview.