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Unregistered
October 29, 2002, 18:46:03
I am experimenting with a Logitech QuickCam 3000 Professional on a USB port and with your help have gotten everything working the way I want. Thanks.
There is a button on the device and I wonder if you know how to "see" it or setup a CallBack routine which responds to it being pressed. Thanks again.
John Oehrle


This message was originally posted by John Oehrle in the old IC Imaging Control Support Forum.

Unregistered
October 30, 2002, 12:48:43
Hello,

We have a Logitech "QiuckCam Web" camera that has a trigger button too. There is no standard DirectShow property for a button like this. (The trigger input provided by SONY DCAM cameras works different: the SONY camera sends out one image right after a trigger signal was detected).
The Logitech driver probably exports a proprietary property for the trigger button, but IC cannot handle it, because it has no "knowledge" about this property.

I am afraid, you will not be able to use the button with IC.

Best regards
Johannes
IC Support


This message was originally posted by IC Support in the old IC Imaging Control Support Forum.

Unregistered
October 31, 2002, 00:33:41
We are using the logitech camera for practice. Our target camera uses usb2.0, has a cypress usb2.0 chip and an Omnivision 1280X1024 (could be other resolutions) cmos imaging chip and has what appears to be a reset button. There is a WDM driver for direct show. Might this driver have the button enumerated as some type of device recognizable by IC?


This message was originally posted by John Oehrle in the old IC Imaging Control Support Forum.

Unregistered
October 31, 2002, 10:48:40
Hello,

If the support for the button is implemented in the WDM stream class driver, you will have to enable the trigger mode for the camera. If the camera is in trigger mode, it will send one image rigth after the button is pressed. As far as I know, there is no DirectShow defined way to read the state of a trigger button or getting an event if a trigger button is pressed.
If the manufacturer of the camera told you the property for reading the button state, you could try to create an COM interface to this property. This would require substantial knowledge about DirectShow programming.

Best regards
Johannes
IC Support


This message was originally posted by IC Support in the old IC Imaging Control Support Forum.

Unregistered
October 31, 2002, 16:13:06
Thanks for your reply. Yes, the last thing I want to do is acquire substantial knowledge about DirectShow programming. I started down that road, several times, after getting the Carnegie Mellon 1394 interface working. But I realized how much easier, and I might add robust, your approach is. I got as far as getting a callback routine working displaying live video. But when I started getting into setting the camera format, or even selecting the camera and all the things that IC makes so easy, I made my choice. Thanks for a great product. I've just learned that the button on the camera we will be using is for capturing a still image. "Push switch, capture image", we've been told. Could there be anything special in the data structure to distinguish a still image from the live stream?
I remain still a little confused,
John Oehrle


This message was originally posted by John Oehrle in the old IC Imaging Control Support Forum.

Unregistered
November 1, 2002, 16:10:52
Hello,

In DirectShow there is a property for enabling an external trigger. If a device supports this property, it behaves in the following way:

if external trigger is enabled and an image stream is started, the device does not send a sample (one image) unless a trigger has occurred. This meas: every time a trigger occurs the device sends out one sample (one image) into the stream.
Usually an external trigger is a TTL pulse.
If the Logitech camera supported this external trigger property, you would have to press the trigger button for every sample that is send into the image stream. But the Logitech driver does not implement the external trigger property, because IC cannot access it.
The driver propably implements a proprietary interface to the button. This means that an application has to access this interface directly by using the DirectShow API.

Best regards
Johannes
IC Support


This message was originally posted by IC Support in the old IC Imaging Control Support Forum.

Unregistered
November 1, 2002, 18:54:58
Thanks again for your response. I guess I'm going to have to get into the DirectShow API after all. We should probably not call the feature we want a trigger, because that is often associated with a signal FROM computer TO camera to cause a frame to be sent. All we are trying to do is get a signal from the operator, who is in the vicinity of the camera, causing the live video display to stop and the last frame to be processed. We could run another wire to an IO card and do the same thing but it is not as clean. Thanks again for all your help.
John Oehrle


This message was originally posted by John Oehrle in the old IC Imaging Control Support Forum.