Abstract: The invention relates to a system and method for processing a polluting region of a digital image of an object (3) acquired using X-rays and comprising points (P) with each of which there is associated a numerical intensity value and at least one item of metadata (M) chosen from among one or more physical parameters of the object, and one or more parameters relating to the power or the energy of the X-rays with which the image was acquired. Said method comprises identifying at least one group of points in the image corresponding to a polluting region on the basis of the initial intensity values I0 of the points in the image and of said metadata. Generating a new image comprises a step of replacing the initial intensity values I0 of at least some of the points of said at least one polluting region with new intensity values.

Abstract: The invention relates to multifrequency acoustic transducers exhibiting a wide band around each resonant frequency. It consists in inserting between a .lambda./2 active emitter plate (201) and the soft reflector (203) which supports it a rear plate (202) resonating in .lambda./4 mode and in placing on this active plate two marcher plates (204, 205) whose impedances are designed so as to best match the two frequencies obtained by inserting this rear plate. Thicknesses of these marcher plates are optimized with the aid of a model of for example Mason type starting from a value close to .lambda./4 for the frequency to be matched. It makes is possible to construct sonar transducers which operate equally well in detection mode and in classification mode.