Pediatric volumetric ultrasound scanner

Apparatus comprising:

• a sensor array including at least one 2D array of acoustic transducer elements;
• a local processor disposed at the sensor array and configured to electronically define one or more active windows within the sensor array, wherein each of the one or more active windows includes a corresponding 2D subarray of acoustic transducer elements of the sensor array, wherein the one or more active windows can be adjustably positioned within the sensor array by the local processor, and wherein only acoustic transducer elements within an active window are active for transmission and/or reception;
• a system processor having a fixed number of beamforming channels, and disposed away from the sensor array, wherein the system processor is configured to provide 2D beamforming by individual control of each acoustic transducer element that is within an active window, and wherein the system processor is configured to tell the local processor where to position each of the one or more active windows;
• wherein the one or more active windows are freely defined by the local processor without reference to any division of the sensor array into fixed hardware-defined subarrays.