Attached Link: http://www.newtek.com/products/lightwave/tutorials/rendering/camera_mapping/camera_mapping.html

Yes, the camera view of the scene affects the mapping. Imagine taking the background image and projecting it out from the camera onto the object being mapped, as if the camera were also a slide projector. As you can see in the examples here, if you then render without changing the camera or object positions, you get something that looks like the original background image, projected onto the objects in front of the camera.

It's "perspective" because it maps the perspective within a photo onto the UVS texture map of the object. At least, that's one way to think of it.

The link I attached is to a tutorial on using a similar feature in Lightwave (where it's called "Front Projection Mapping" or "Camera Mapping", which makes more sense). The mechanics will obviously differ, but the principles are the same.