A method of producing a synthetic aperture of composite acoustic waveforms by an acoustic imaging device, comprising: synthesizing, in one or more waveform synthesizers, one or more composite waveforms, wherein a composite waveform is formed of a plurality of individual orthogonal coded waveforms that are mutually orthogonal to each other and correspond to different frequency bands, such that each of the individual orthogonal coded waveforms includes a unique frequency with a corresponding phase; transmitting, from one or more transmitting positions relative to a target, two or more composite acoustic waveforms comprising a plurality of acoustic waveforms (131a,... 131n), wherein the transmitting includes selecting two or more transducer elements of an array to transduce the plurality of individual orthogonal coded waveforms of the respective two or more composite waveforms into the plurality of corresponding acoustic waveforms (131a,... 131n) of the respective two or more composite acoustic waveforms; and receiving, at one or more receiving positions relative to the target, returned acoustic waveforms that are returned from at least part of the target corresponding to the transmitted acoustic waveforms, wherein the receiving includes selecting at least some of the transducer elements of the array to receive the returned acoustic waveforms, wherein the transmitting positions and the receiving positions each include spatial positions of transducer elements in the array of transducer elements relative to the target and/or beam phase center positions of the array, wherein the selecting the two or more transducer elements of the array in transmitting the two or more composite acoustic waveforms and the selecting the at least some of the transducer elements of the array to receive the returned acoustic waveforms produce a synthetic aperture of the acoustic imaging device, wherein, in transmitting the acoustic waveforms to the target, controlling the transducer elements of the array to cause the two or more composite acoustic waveforms to change in orientation with respect to the target so that the target receives the acoustic waveforms (131a,... 131n) at different waveform orientations over an imaging period, and wherein the controlling the transducer elements of the array includes changing the beam phase center positions of the transmitted acoustic waveforms (131a,... 131n) on the two or more transducer elements of the array to cause the change in orientation of the two or more composite acoustic waveforms with respect to the target. synthesizing, in one or more waveform synthesizers, one or more composite waveforms, wherein a composite waveform is formed of a plurality of individual orthogonal coded waveforms that are mutually orthogonal to each other and correspond to different frequency bands, such that each of the individual orthogonal coded waveforms includes a unique frequency with a corresponding phase; transmitting, from one or more transmitting positions relative to a target, two or more composite acoustic waveforms comprising a plurality of acoustic waveforms (131a,... 131n), wherein the transmitting includes selecting two or more transducer elements of an array to transduce the plurality of individual orthogonal coded waveforms of the respective two or more composite waveforms into the plurality of corresponding acoustic waveforms (131a,... 131n) of the respective two or more composite acoustic waveforms; and receiving, at one or more receiving positions relative to the target, returned acoustic waveforms that are returned from at least part of the target corresponding to the transmitted acoustic waveforms, wherein the receiving includes selecting at least some of the transducer elements of the array to receive the returned acoustic waveforms, wherein the transmitting positions and the receiving positions each include spatial positions of transducer elements in the array of transducer elements relative to the target and/or beam phase center positions of the array, wherein the selecting the two or more transducer elements of the array in transmitting the two or more composite acoustic waveforms and the selecting the at least some of the transducer elements of the array to receive the returned acoustic waveforms produce a synthetic aperture of the acoustic imaging device, wherein, in transmitting the acoustic waveforms to the target, controlling the transducer elements of the array to cause the two or more composite acoustic waveforms to change in orientation with respect to the target so that the target receives the acoustic waveforms (131a,... 131n) at different waveform orientations over an imaging period, and wherein the controlling the transducer elements of the array includes changing the beam phase center positions of the transmitted acoustic waveforms (131a,... 131n) on the two or more transducer elements of the array to cause the change in orientation of the two or more composite acoustic waveforms with respect to the target.