Ultrasound machine providing composite image data

An ultrasound imaging system combines successive images of a time series to produce high-resolution ultrasound. A piecewise registration process and deemphasizing of high-frequency spatial components may be used to aid in the combination process. A high-definition image may be obtained with or separately from this process by combining different images obtained with different ultrasound frequencies. The images are weighted to accentuate the contribution of high-frequency ultrasound data at the leading edge of imaged structure.