Twain Webcams

Discussions about TWAIN & WIA scanning in GdPicture.NET using GdPictureImaging.
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rajnambiar
Posts: 5
Joined: Sun Feb 13, 2011 2:03 pm

Twain Webcams

Post by rajnambiar » Sun Feb 13, 2011 2:12 pm

I am trying to capture an image from web cam, automatically every 10 minutes. Eventhough hudeui is true, another window pops up from the side of cam asking me to select the frame from camera. This requires the user to select the frame, but I need to capture without user pressing any keys since there won't be any user. I do not want to send keystrokes to that pop-up window, since I know how unreliable that can be.

1. How do I capture the frame without user intervention?

2. If the problem lies with the webcam (I tried microsoft lifecam, iball, creative and genius wbecams - all of them work with GDTwain, but brings the selection-form up. Selection for is exactly same.), then is there any other camera that would suit my requirement?

3. The "select frame" form that pops up, is exactly same for all four webcams. Is this some kind of standard response? Would you know whether Logitech also displays the same message? I haven't tried logitech.

In trouble. Please guide.

Thanks in advance, Raj Nambiar

rajnambiar
Posts: 5
Joined: Sun Feb 13, 2011 2:03 pm

Re: Twain Webcams

Post by rajnambiar » Mon Feb 14, 2011 1:24 pm

For the same camera, I am able to take a snapshot using wia and VB without the GUI interfering it! Please check this link

http://www.vbforums.com/showthread.php?t=499052

It allows me to take the snapshot of the current frame, without the camera popping up forms asking me to select frames, which happens when I use GDTWAIN ActiveX. Is there some setting that I am not using in GDTWAIN to achieve a simple camera shot? Or GDTWAIN itself missing this feature? Please guide.

rajnambiar
Posts: 5
Joined: Sun Feb 13, 2011 2:03 pm

Re: Twain Webcams

Post by rajnambiar » Tue Feb 15, 2011 9:09 am

Attached the dialog boxes. First, I get to select the source - it is an Iball webcam. In the next form that pops up, I am asked to select the frames. In the VB6 example in the link, it uses API calls for WIA, and it can select current frame. Is there anyway I can achieve this? I can send keystrokes to the form and select the frame, but if I can capture a single frame without doing all this, it would be great. Please guide.
Attachments
frameselection_dialogbox.jpg
selectsource.jpg
selectsource.jpg (23.16 KiB) Viewed 4383 times

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Loïc
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Re: Twain Webcams

Post by Loïc » Thu Feb 17, 2011 6:03 pm

Hi,

The sample you refer use WIA API. GdTwain uses only TWAIN. What you are doing with GdTwain is using the WIA service via a WIA layer on top of TWAIN. But unfortunately you can control all WIA api by this way.

We support native WIA transfer in GdPicture.NET only.

With best regards,

Loïc

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