The USPTO awarded Apple with a patent for dual-sensor system that is designed to help its devices take better photos.
It has two image sensors, according to the patent application. The device or process then checks the images pixel-by-pixel looking for problems with the photos. If it finds one it deems unacceptable, it will replace it with content from the other sensor.
This isn’t limited to the cameras on iOS devices. It applies to Macs and probably any other Apple devices with cameras. It can also be used for video capture.
There’s much more to it, but in the most basic of terms, it sounds like it pretty much takes two photos and uses the best bits of each to make one complete image. At least that’s what this seems to describe.