System energy model for a digital ultrasound beamformer with image quality control

As the lateral resolution and axial imaging depth of a ultrasound image increase, so do the number of transducer elements and the corresponding processing units. Conventional ultrasound systems are often large and expensive due to the intensive requirement of large beamforming arrays. But for applications such as point-of-care diagnostics in rural areas, the movement to a portable and low-power ultrasound imaging system is warranted. To address the low power requirement for portable applications, the proposed beamformer operates in one of three modes, namely quarter, half, and full resolution modes, selectable at runtime. In the first two modes, a subset of elements, with effective pitches of 4x and 2x of the transducer pitch, are processed for low quality images of the full region of interest. These modes provide run-time power reduction, because the Analog Front End (AFE) and Analog-to-Digital Converter (ADC) for the unused channels can be turned off by the feedback control signals from the beamformer. Based on the low quality image, the user can intuitively specify a smaller region where a higher quality image is desired, and the full resolution beamforming mode is used. A system energy model is set up to evaluate the image quality and frame rate performance, while providing realistic power consumption predictions. The model offers fast and accurate behavioral level understanding of the ultrasound system under optimization.