Hi;

I'm planning to use DotTwain for the following situation:

I need to be able to use a Twain complaint  WebCam to capture individual images at certain interval times (e.g. 15 seconds) and then send it to the server.

Solution A: Use a .Net WinForm to create an app and use DotTwain to capture the image and use some type remoting to send the image. The problem with this approach, is that user has to install .Net, application, DotTwain.dll and third party remoting system. Plus I have to worry about updates for each user.

Solution B: Use ASP.Net instead and I don't have worry about installing stuff on user's machine and updates. But the question is, Can I control the page in browser to take picture at certain interval times like I would with WinForm.

Any detailed info is appreciated!

Thanks!

..Ben
 

There is one main issue you are likely to run into; I've never seen a webcam that will allow you to take a picture without the user interface.  They don't allow it because it would introduce security issues.  While you can call Acquire every 15 seconds, I'm pretty sure the user would have to click a button on the user interface to take the picture.

---

Glenn Chittenden Jr.
Atalasoft Development Team

Glenn:

There is one main issue you are likely to run into; I've never seen a webcam that will allow you to take a picture without the user interface.  They don't allow it because it would introduce security issues.  While you can call Acquire every 15 seconds, I'm pretty sure the user would have to click a button on the user interface to take the picture.

Hi Glenn;

Thanks for the reply; Is this the nature of all the "WebCams" in general?

Well, let me pose the question a different way. I don't have to use a "WebCam", but I need to capture still images every few seconds and send it to the server.

My first thought was to use analog camera and use a image capture board. But the seems to have become old and expensive. So, my next move was to use a "WebCam" to tell the camera to capture a "Digital" picture using TWAIN system like yours.

So, what else can I use that I can automate the image capturing?

I also need to be able to use the same camera to capture a product image and save into database, in this case I would provide an interface for the user to click to capture and then save.

As I was reading the manual, it says that I need to use a WinForm to control the TWAIN system. I don't see any problem, but do you think I can also approach this using SilverLight 1.1 where I can use C#, instead of WinForm?

 

Sorry, too many questions!

Thanks! 

Hi Glenn;

As I spent some time on Logitech forum and reading stuff, it seems like Logitech is dropping TWAIN support in their newer cameras and new drivers. They seem to be going towards Microsoft Windows Image Acquisition (WIA).

Now the question come to you [expert] guys. Do you have any plans of giving us a nice and easy to use wrraper for .Net framework? ;-)

Thanks! 

WIA has a Twain compatibility, although not the greatest, so WIA drivers already work with DotTwain.  I don't think we have any plans for a WIA specific component.

As for using Silverlight; I think we tested with a XAML app but I can't remember if we were able to get it working.  The main issue with TWAIN is that is requires a window message loop to pass messages through the application.  Plus is has to run client-side in order to access any devices on the client system, so it has to be a thick client with full trust permissions.

---

Glenn Chittenden Jr.
Atalasoft Development Team

Hi Glenn;

Thanks for detail reply. I'm now trying to install this new Logitech camera on Win2000 and no luck. two times installation, and the software thinks there is another software is using the camera.

But I just found out that this camera works only on XP and Vista. Now I need to try it another machine.

I'll be in touch. Thanks! 

We are looking for similar functionality.  We are writing a Thick/Smart Client application that we would like to take a picture from a connected digital camera.  Anyone have any idea how to do this?

 If not, can we at least pull the images via dotTwain?

If the camera has a TWAIN driver, then you can use DotTwain to acquire images from it.  It just can't be done without user interaction.

---

Glenn Chittenden Jr.
Atalasoft Development Team