Automatic gain control for a small portable ultrasound device

Among the recent innovations in ultrasound is a new portable cardiac ultrasound device being developed at Agilent Technologies’s Healthcare Solutions Group. Such a device, because of its size, can be used in many more locations than a traditional ultrasound machine, and thus potentially by many people without the same extent of training as a cardiologist or sonographer. To facilitate this type of usage, the device requires an easyto-learn user interface, incorporating simplifying features such as automatic gain control (AGC). This project developed and evaluated prototype, real-time AGC algorithms for 2D cardiac ultrasound, implemented in software. A view-based AGC algorithm was first considered, and shown to be unsuccessful. The second AGC algorithm considered has two components: the first is a classification component that designates blocks of acoustic data as consisting primarily of blood, ordinary tissue or specular tissue samples; the second component adjusts the 2D gains such that the brightness of the image is appropriate for the given classifications. Several versions of this classification-based AGC algorithm were qualitatively evaluated by clinical specialists. Preliminary results show that some of these algorithms produced images of a quality similar to that of images produced by an experienced sonographer using a device with manual gain controls, although these AGC algorithms are not very aggressive in their alteration of gain settings from the preset values. The results also suggest that even experienced clinical specialists prefer the convenience of automatic gain control over the precision of manual gain control for a screening device. Om Sai Ram Table of