are there cameras which can capture images through opaque window glass? forget the infrared filters n stuff?

Answer 1

Why forget the stuff that is probably going to work?
And how opaque is the glass? Frosted white or opal glass?
The simple answer is that there is no visible light camera that is going to take pictures through glass that won't pass visible light, which is the definition of opaque.

Answer 2

concerning to the different remark, the lenses on IR cameras are created from germanium, no longer glass. Glass, as a results of fact of its crystaline shape, is a sturdy insulator and our residences earnings from the actuality that tumbler keeps warmth out interior the summertime and warmth in during the winter with the help of blockading infrared wavelength penetration. Germanium's crystaline shape helps IR wavelengths to bypass by way of to the cameras detector.