We used inexact adders to process images and found that relative errors up to 0.54 percent were almost indiscernible, and relative errors as high as 7.5 percent still produced discernible images.
One of the advantages of NPR techniques is that it is efficient. Instead of following the arms-race of ever-increasing numbers ray-tracing (times x bounces) it works with approximations. It also swallows errors within the look determined by the artist. So when I read about this very efficient but imperfect computer chip developed at Rice University (link above to the gizmag review), I couldn’t help but exclaim: “Wow! An NPR chip!” For the first time, I find myself longing not just for NPR software, but an NPR computer to boot.