RAISR stands for Rapid and Accurate Image Super-Resolution. It’s Google’s prototype software which utilises machine learning to provide better quality upsampling of low resolution images. They first showed off the technology in November last year, but now Google have announced that RAISR has been implemented into Google+ for Android.
The point of the technology is to save bandwidth. Many mobile users have fairly limited bandwidth. Either they have low limits, or it’s just slow. Google see RAISR as an option to save bandwidth. The idea is to scale down the images before sending out. This means they’re smaller and easier to send. Then RAISR blows them back up to their original size on the receiving end. And it wants to do this with the minimal of impacts on quality.