Accessing two identical Logitech Cameras simultaneously ... Matlab freezes (for a while)

Hi,

I am working with two idenical Logitech HD C910 webcameras. Accesing images via getsnapshot from each is working fine! Previewing each of them is working fine as well!

BUT: If I type following:

L = videoinput('winvideo', 1, 'RGB24_320x240');
R = videoinput('winvideo', 2, 'RGB24_320x240');
preview(L);
% even with pause(x) here
preview(R);

Matlab is "Busy" for 2-3 minutes, preview window 1 (winvideo-1) is freezing and preview window 2 is black. Matlab comes back with:

??? Error using ==> imaqdevice.preview at 181
winvideo: Image acquisition device is not accessible.
Ein an das System angeschlossenes Gerät funktioniert nicht.
Make sure no other objects or applications are accessing the same device.

When using imaqtool both have different IDs (1 and 2), but when I type:

get(R,'Source'), get(L,'Source')

both prompt:

   Display Summary for Video Source Object:

        Index:   SourceName:   Selected:
        1        'input1'      'on'

Might that be the problem here? How can I fix it? Since afaik there is no "Set" on "Sourcename" and "Index" ...

It seems - anyhow - Matlab is accessing the same device?! But, when using preview (not simulatenously) I definetely have two different streams (L and R) ... hmm ....

I've also installed a new driver, deactivated Logitech software ...

Any ideas, comments, tricks?

Cheers, Daniel

Answer 1

[David Tarkowski]

I've seen similar issues in the past which were caused by the camera drivers. Probably the simplest thing to do is configure the cameras to use the generic UVC driver which ships with Windows instead of the the Logitech drivers. The Logitech website has instructions on how to switch from the UVC drivers to the Logitech drivers. The same basic steps apply in going the other direction.

[Daniel]

Sorry for the late reply ... had one week off! ;)

Excellent solution ... so (damn) easy! it works fine! (so far) ... :)

Cheers Daniel