  We describe a general method to determine the location of a point source of
waves relative to a two-dimensional active pixel detector. Based on the
inherent structural sensitivity of crystalline sensor materials, characteristic
detector diffraction patterns can be used to triangulate the location of a wave
emitter. As a practical application of the wide-ranging principle, a digital
hybrid pixel detector is used to localize a source of electrons for Kikuchi
diffraction pattern measurements in the scanning electron microscope. This
provides a method to calibrate Kikuchi diffraction patterns for accurate
measurements of microstructural crystal orientations, strains, and phase
distributions.
