In diagnostic ultrasound, what does apodization and subdicing be going to?

Apodization is a method for reducing side lobes in some arrays. It at a snail`s pace decreases the jolting of the transducer surface with distance from it's center. It is usually skilful by using more power to excite the innermost elements. Subdicing is a technique used to overcome grating lobes: each focal transducer element is devided into smaller parts, respectively one being a partly wave length.