Ultrasound imaging using complementary codes

An ultrasound imaging system for imaging a sample, comprising:

• an array of ultrasound transducers;
• a transmitter for driving the array of ultrasound transducers;
• a receiver that receives ultrasonic reflections from the sample;
• 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;
• and
• a controller comprising instructions to, for each sub-image capture event, cause the transmitter to transmit a sequence of transmit events from the ultrasound transducers, each transmit event comprising a plurality of distinct waveforms directed toward separate focal zones on the sample, and the sequence of transmit events comprising a sequence of distinct waveforms directed toward each focal zone, wherein a cross-correlation level of the distinct waveforms in each transmit event is below a predetermined threshold, and wherein each sequence of distinct waveforms directed toward each focal zone are complementary.