How can I retrieve the memory from an ActiveX IVideo Portal?

[Wheels]

Hi,
I am using the ActiveX IVideo Portal to capture images from a web cam. I need to access a 2-D array corresponding to the pixel information. When I write the image to file and convert to bitmap within a loop, the access to the 2-D data is slow and lags at least a second behind the camera. Would it be faster to write to memory (there is a PictureToMemory Method)? If so, how do I access this memory and the Pixmap or bitmap it contains? Thanks very much
-ND

[rolfk]

Wheels wrote:

> I am using the ActiveX IVideo Portal to capture images from a web cam.
> I need to access a 2-D array corresponding to the pixel information.
> When I write the image to file and convert to bitmap within a loop,
> the access to the 2-D data is slow and lags at least a second behind
> the camera. Would it be faster to write to memory (there is a
> PictureToMemory Method)? If so, how do I access this memory and the
> Pixmap or bitmap it contains? Thanks very much

This is Logitech Quickcam isn't it?

Well, not simple at all. Basically you need to do very much magic in
LabVIEW alone or much better yet write a function in a DLL to do the
nitty gritty work.

However the Quickcam Active X type library has a bug in that it tells
LabVIEW to treat the
data pointer as output only but in fact it should
be an input and output in order to make proper use of that method. this
is from the Logitech SDK 4.0.1 or something but last time I checked
(last year) this was still the most recent version. Logitech didn't even
acknowledge my bug report about two and a half years ago or so.

As it is now you really can't use the PictureToMemory method at all in
any language which does rely on the type library to learn how to call
the method. That pretty much leaves only C++ (and maybe Delphi) as an
option. I tried to fix the type lib with a hex editor, but Windows keeps
reinstalling the according shared library sooner or later as it detects
tampering with it somehow.

Rolf Kalbermatter