150 MHz in vivo ultrasound of the skin: imaging techniques and signal processing procedures targeting homogeneous resolution

The range of possible applications of an ultrasound imaging system is usually limited by the maximum resolution and penetration depth of the system. Both requirements are inversely concurrent to each other, as the resolution improves with rising frequencies while the penetration depth lowers. Thus, it is useful to develop procedures, which give rise to better resolutions in both, axial and lateral directions, while the penetration depth, which is specified by the application, is kept constant. To meet this goal, we use sophisticated imaging techniques (SAFT, B/Z-scan) enabling the employment of high focused transducers combined with an adapted pulse compression method, which takes the transfer functions of the system and the tissue into account. Those procedures have been implemented in an ultrasound imaging system suited for in vivo skin or eye examinations working in the frequency range from 20 to 150 MHz