Focusing technology is used in order to reduce the artifacts that occur geometric error on the hardware equipment.
TomoShop® extract geometry error automatically that occur in hardware equipment by focusing technology and high versatility of Omni back-projection technology, then it reduces the artifacts of reconstructed images. It is done by GPU with high-speed computing technology.
Focusing process can be done by minimizing the size of data of reconstruction images and Image quality evaluation function that caliber based on group theory (mathematical programming) optimization mathematically.
There was a method using Entropy function with Information theory . However, it loses uniqueness of minimum value and reduces stability of optimization algorithm, which is shown below.
TomoShop® can reduce artifact with setting the evaluation function even if there are noises, so that the optimization algorithm converges to robust images and bring more accurate assessment of geometric errors that occurred.
 Y. Kyriakou, R.M. Lapp, L. Hillebrand, D. Ertel and W.A. Kalender, Simultaneous Misalignment Correction for Approximate Circular Cone-Beam Computed Tomography, Phys. Med. Biol. Vol. 53, No. 22, pp. 6267-6289, 2008.