Dynamic focus

Focusing is the method of adding the data of several in such a manner, that all of them are "in phase", meaning, they are individually delayed, to compensate the differences in the time of flight. This would be easy to accomplish, if the distance to the object, that is to be resolved was know. In an ultrasound measurement, this is not the case (hence the term measurement), so a focusing strategy has to applied, that allows making the focusing calculations, without having to repeat the measurement with different focal lengths.

For dynamic focusing the data of several channels is stored in a fast memory. So the focusing calculations can be carried out, after a scanline is captured, without having to repeat the measurement.