[Front cover]

A Compact Schlieren System for Ultrasound Beam Imaging is shown on the cover. A new compact Schlieren system (40 cm x 100 cm x 40 cm) for ultrasound beam imaging and tomography based on an optical fiber laser source has been developed at Acoustoelectronics Laboratory (ACULAB), University Roma Tre, Italy. The optical beam is focused by means of 2.54 cm diameter lenses. Images are obtained by mechanically scanning the entire ultrasound field up to 20 cm length, and merging several sub-images. The correct merging of the sub-images, which is impeded by luminance artefacts due to both the spatial Gaussian distribution of the light source and the non-ideal optical components including lenses, screen and camera, is carried out by an adaptive filtering algorithm developed by the contributors. The left figure is an axial scan of a 3 cm ultrasound field (the emitting surface is on the top) of a 10 MHz ultrasonic transducer for ophthalmic applications. The three figures on the right are, starting from the top, the tomographic sections of the beam at 5 mm, 15 mm, and 25 mm, respectively.