In Nissan's demonstration video (after the source link below), the Intelligent Rear View Mirror is used to see "through" a bunch of balloons filling the back of the big Armada. In the real world, Nissan says, the mirror can be used to see through any obstruction behind the driver, including tall passengers, bukly items in the cargo space, and so on.
The mirror works by allowing the driver to switch between a standard, glass mirror (as found in any vehicle) and a camera mounted on the back of the SUV. When switched to camera view, the mirror's surface becomes an LCD display showing the rear camera's view, thus seeing "through" objects in the Armada that would otherwise obstruct the driver's view.
The Intelligent Rear View Mirror (I-RVM) was introduced by Nissan in 2014 as a concept for a traditional rear view mirror replacement. The I-RVM is switched from standard mirror mode to intelligent LCD mode with a switch located on the bottom of the mirror about where the dimmer switch would normally be on a standard in-car rear view mirror.
The I-RVM uses a high-performance, narrow-angle camera located at the rear of the 2018 Armada. The aspect ratio of the camera is matched to the mirror's approximate 4:1 ratio (versus 4:3 or 16:9 for conventional monitors). A wide-angle camera would become fuzzy and mis-aligned with the mirror's required aspect ratio. The mirror itself is sized to be within US federal guidelines for a rear view mirror to both comply with regulations and to make it comfortable to use for consumers used to standard mirrors.
Nissan says that the mirror's structural design was designed specifically to overcome image overlap, where the mirrored surface would reflect on top of the LCD's output, though hasn't revealed exactly how this is achieved.
The I-RVM will debut on the topmost trim level of the 2018 Nissan Armada, the Platinum, which starts at US$61,590 (not including destination fees). The I-RVM will be standard equipment on the Platinum package. That demo video can be seen below.