An ultrasound imaging system for imaging a sample has an array of ultrasound transducers, a transmitter for driving the array of ultrasound transducers, a receiver that receives ultrasonic reflections from the sample, and a processor that generates an image of the sample based on a set of sub-image capture events, each sub-image capture event comprising received ultrasonic reflections. For each sub-image capture event, the transmitter transmits a sequence of transmit events from the ultrasound transducers. Each transmit event comprises a plurality of distinct waveforms directed toward separate focal zones on the sample. The sequence of transmit events comprises a sequence of distinct waveforms directed toward each focal zone. The cross-correlation level of the distinct waveforms in each transmit event is low, and the sequence of distinct waveforms is complementary.
