Active helical scanner for detecting structure embedded in medium in three-dimensional mode has pitch of spiral-shaped movement path less than width of overlap between receiving and emission spaces

摘要

The scanner includes a transmitter with a cone-shaped beam, and a receiver that moves in a spiral across the structure. A first acoustic module (1) has transmitters with a corresponding emission space. A second acoustic module (2) has receivers with a corresponding receiving space. The acoustic modules lie precisely opposite each other, with the structure arranged between them. The emission space of the transmitters and the receiving space of the receivers overlap as much as possible in the region of the unknown structure. The pitch of the spiral shaped movement path is less than or equal to the width of the overlap of the receiving space with the emission space. A transmission-reception cycle is performed in steps which are equal to or less than the diameter of the overlap of the receiving space with the emission space. The transmission signal is modulated using a suitable modulation function. Independent claims are included for two further active helical scanners, and for an information processing unit.