Depth of field improvements and automatic focusing in long wavelength imaging systems / Ahmed Yamani (1984)

Depth of field improvements and automatic focusing in long wavelength imaging systems [texte imprimé] / Ahmed Yamani, Auteur ; Benson, F. A, Directeur de thèse . - Sheffield : [s.n.], 1984 . - 168 f. : ill. ; 30 cm.
PhD Thesis : Electronics : University of Sheffield : 1984
Bibliogr. f. 164 - 168
Langues : Anglais (eng)

Mots-clés :	Imaging systems Field improvements Long wavelength
Index. décimale :	D004284
Résumé :	A novel approach to the depth of field limitations associated with backward propagation techniques is developed. The new technique does not require prior object range information to reconstruct simultaneous in-focus images of targets situated at widely different ranges. furthermore, the distortion associated with backward wave propagation is removed when this technique is used. Although the proposed procedure is multifrequency in nature, the bandwidth used is shown to be well within that of a typical transducer and, thus, it can be used in other imaging systems operating in either the electromagnetic or acoustic regimes.