1. An X-ray imaging device, comprising: an X-ray source; a square or rectangular X-ray detector; and a collimator comprising an X-ray attenuating material with an aperture therein, the collimator configured to produce an X-ray image with a superellipse shape having a first substantially straight edge and a second substantially straight edge running substantially perpendicular to the first edge, wherein the first and second edges do not physically intersect with each other at 90 degrees.