A method of generating an image of a scanned subject includes: emitting, by multiple ultrasonic elements of an array, multiple respective ultrasonic signals into a subject, the multiple respective ultrasonic signals defining at least two beam portions traveling in different directions； receiving, by the multiple ultrasonic elements, multiple respective ultrasonic echo signals； and generating at least one image of a portion of the subject from the received multiple ultrasonic echo signals. A negatively focused wavefront including the at least two beam portions traveling in the different directions may be emitted. Multiple negatively focused wavefronts may be generated and emitted.
