do that only with ASP.Net,
But you can go for SilverLight,
Here is an example about how to scan an image with SilverLight from WIA supported devices:
This example is about running solverlight out of browser, I am not sure if you can do same thing from user's browser or not. But i don't think this could be possible.
So I only can think about ActiveXs that are only supported by IE. Or Java applets.
Google them. You can find good results for JTWIN and TWIN ActiveX