Did you try TwainX, it says.
"Easily integrate Scanners into your web-based applications with a minimum of ... of indirection"
http://twainx.sourceforge.net/
If this is an internal scanner accesible to your company, there is sense in doing this, but if the general public has to do it, they will have to install the activex and all, not recommending your approach. Might as well ask the user to scan it, and then upload the image.