G. Chiorboli et Gp. Vecchi, DESIGN OF FIDUCIALS FOR ACCURATE REGISTRATION USING MACHINE VISION - COMMENT, IEEE transactions on pattern analysis and machine intelligence, 15(12), 1993, pp. 1330-1332
Subpixel registration accuracy improves by one order of magnitude if i
mages are not binarized as indicated in the referenced paper, but gray
scale information is fully exploited in calculating centroid position
.