ICARUS: imaging pulse compression algorithm through remapping of ultrasound.
In this work we tackle the problem of applying to echographic imaging those synthetic aperture focusing techniques (SAFT) in the frequency domain commonly used in the field of synthetic aperture radars (SAR). The aim of this research is to improve echographic image resolution by using chirp transmit signals, and by performing pulse compression in both dimensions (depth and lateral). The curved geometry present in the unfocused radio-frequency (RF) ultrasonic image is the main cause of inaccuracy in the direct application of frequency domain SAFT algorithms to echographic imaging. The focusing method proposed in this work, after pulse compression in the depth dimension, performs lateral focusing in the mixed depth-lateral spatial frequency domain by means of a depth variant remapping followed by lateral pulse compression. This technique has the advantage of providing a resolution that is uniform in nonfrequency selective attenuation media, and improved with respect to conventional time domain SAFT, without requiring the acquisition and processing of channel data necessary for the most advanced synthetic transmit aperture techniques. Therefore, the presented method is suitable for easy real-time implementation with current generation hardware.
Biagi
Elena
E
Laboratorio Ultrasuoni e Controlli Non Distruttivi, Dipartimento di Elettronica e Telecomunicazioni, Università di Firenze, via S. Marta 3, 50139 Firenze, Italia.
Dreoni
Nicola
N
Masotti
Leonardo
L
Rossi
Iacopo
I
Scabia
Marco
M
D000465:Algorithms; D007089:Image Enhancement; D019047:Phantoms, Imaging; D012815:Signal Processing, Computer-Assisted; D014463:Ultrasonography / Q000379:methods*