150 Mhz Adaptive Ultrasound Imaging of the Eye and Skin
The growing interest in high resolution noninvasive imaging gave rise to the development of high frequency ultrasound imaging systems1,2,3,4. A major design problem concerning these broadband systems is caused by the strong dispersive attenuation of the tissue, which results in inhomogeneous images with poor signal to noise ratio (SNR). To address the noise problem, strongly focused transducers with high energy density in a narrow focal region are utilized, which also provide more isotropic images due to improved lateral resolution. To account for the short depth of the focal area a suitable imaging conception, the B/Z-scan concept5 is used. To avoid the inhomo-geneity of the images, different transmitter signals for each depth are applied, which are pseudoinversely prefiltered according to the transfer function of the covering tissue. To gain signal energy required for inverse filtering, a pulse compression technique with nonlinearly frequency modulated chirp signals is utilized6,7.
KeywordsPulse Compression Linear Frequency Modulate Chirp Signal Inverse Filter High Frequency Ultrasound
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