Beam pattern for 3 imaging modalities. Vertical lines represent beam shape and, thus, resolution, for each of 3 modalities. Gray circles within beam represent stones and blue objects outside beam represent appearance of stone as function of resolution. Arrows represent signal-to-noise where black is high and white is low. In conventional ray line imaging resolution is enhanced at user selectable focus, at sacrifice of pre-focal and post-focal resolution (A). In spatial compound imaging, image uniformity is improved but shadowing can be reduced and stone and shadow boundaries defocused (represented by dotted edges of hourglass shaped beam) by compounding images that have different angles of approach to stone (B). Harmonic imaging is similar to ray line imaging but builds image from higher frequency signals to improve lateral resolution, at sacrifice of signal-to-noise and penetration depth (C). By setting focus much deeper to stone, beam is more uniform across depth.