Resolution limitation of travel time tomography: beyond the first Fresnel zone

2013 ◽  
Author(s):  
Cuiping Li ◽  
Neb Duric
Keyword(s):  
Travel Time ◽  
Fresnel Zone ◽  
Travel Time Tomography

scholarly journals Zone-Shrinking Fresnel Zone Travel-Time Tomography for Sound Speed Reconstruction in Breast USCT

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5563
Author(s):  
Xiaoyue Fang ◽  
Yun Wu ◽  
Junjie Song ◽  
Hang Yin ◽  
Liang Zhou ◽  
...  
Keyword(s):  
Travel Time ◽  
Sound Wave ◽  
Sound Speed ◽  
Breast Imaging ◽  
Fresnel Zone ◽  
Weighting Factor ◽  
Reconstruction Accuracy ◽  
Low Contrast ◽  
Travel Time Tomography

Many studies have been carried out on ultrasound computed tomography (USCT) for its potential application in breast imaging. The sound speed (SS) image modality in USCT can help doctors diagnose the breast cancer, as the tumor usually has a higher sound speed than normal tissues. Travel time is commonly used to reconstruct SS image. Raypath travel-time tomography (RTT) assumes that the sound wave travels through a raypath. RTT is computationally efficient but with low contrast to noise ratio (CNR). Fresnel zone travel-time tomography (FZTT) is based on the assumption that the sound wave travels through an area called the Fresnel zone. FZTT can provide SS image with high CNR but low accuracy due to the wide Fresnel zone. Here, we propose a zone-shrinking Fresnel zone travel-time tomography (ZSFZTT), where a weighting factor is adopted to shrink the Fresnel zone during the inversion process. Numerical phantom and in vivo breast experiments were performed with ZSFZTT, FZTT, and RTT. In the numerical experiment, the reconstruction biases of size by ZSFZTT, FZTT, and RTT were 0.2%~8.3%, 2.3%~31.7%, and 1.8%~25%; the reconstruction biases of relative SS value by ZSFZTT, FZTT, and RTT were 24.7%~42%, 53%~60.8%, and 30.3%~47.8%; and the CNR by ZSFZTT, FZTT, and RTT were 67.7~96.6, 68.5~98, and 1.7~2.7. In the in vivo breast experiment, ZSFZTT provided the highest CNR of 8.6 compared to 8.1 by FZTT and 1.9 by RTT. ZSFZTT improved the reconstruction accuracy of size and the relative reconstruction accuracy of SS value compared to FZTT and RTT while maintaining a high CNR similar to that of FZTT.

Three-Dimensional Acoustic Travel-Time Tomography of the Atmosphere

2008 ◽  
Vol 94 (3) ◽  
pp. 349-358 ◽  
Author(s):  
Sergey N. Vecherin ◽  
Vladimir E. Ostashev ◽  
Keith D. Wilson
Keyword(s):  
Travel Time ◽  
Three Dimensional ◽  
Travel Time Tomography ◽  
Acoustic Travel Time
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