Abstract: An apparatus for the scanning of objects by means of ultrasound echography, comprising a mosaic (10) of ultrasound transducers which is connected to a transmitter stage (20) and a receiver stage (30) for the reception and processing of the ultrasound echos corresponding to the obstacles encountered by the transmitted signals in their direction of propagation, and also comprising a display stage (40). The transducers of the mosaic (10) are grouped in 2.sup.n subwindows in which a non-corrected echogram of an area of the objects scanned is formed. The receiver stage (30) comprises a device for determining correction delays to be applied to delay devices (61 . . . 68), said device comprising 2.sup.n -1 intercorrelation circuits (101,102, etc.) which operate on the basis of n successive divide-by-two operations of the aperture of the mosaic (10).