Abstract

Time-delay estimation is a widely used signal processing task in many areas of ultrasound medical imaging and the performance of many applications is highly dependent on the accuracy and efficiency of the time-delay estimates. Time-delay estimation determines the displacement between two ultrasound echo signals. In this thesis, we propose a new time-delay estimation algorithm, which generates a zero-crossing curve to compute the time-delay estimate between two ultrasound echo signals. A comparative study, using statistical analysis and quantitative measurement of image quality in simulated and experimental ultrasound elastography, was done to compare the performance of the proposed algorithm with other established algorithms, such as normalized cross-correlation (NCC) and sum squared differences (SSD). The results of comparison of various algorithms using signal-to-noise and contrast-to-noise ratios indicated that the new algorithm only marginally improved the quality of the images in ultrasound elastography. In addition, a novel strain map normalization method was implemented to enhance target visualization in ultrasound elastography by compensating for strain decay with depth.

Highlights

  • For thousands of years [1] palpation has been used as a diagnostic tool to detect soft tissue abnormalities

  • Without interpolation of the data, the proposed algorithm had higher SNRe and contrast-tonoise ratio (CNRe) compared to normalized cross-correlation (NCC) and sum squared differences (SSD), but it had lower SNRe and CNRe compared to NCC and SSD with cosine curve fittings

  • The results indicates that NCC benefits more from curve fitting than from interpolation of the RF data and on contrary SSD benefits more from interpolation of the RF data than from cosine curve fitting

Read more

Summary

Introduction

For thousands of years [1] palpation has been used as a diagnostic tool to detect soft tissue abnormalities. Palpation is a subjective and an unreliable method for the assessment of tissue elasticity because tissue abnormalities which are smaller in size and deeper beneath the skin surface cannot be generally detected. The performance of many signal processing applications is dependent on the accurate estimation of the relative time-delay between a reference and a delayed echo signals. Time-delay estimation, in medical ultrasound imaging, has applications in areas such as tissue elasticity imaging [2], [3], [4], [5], blood flow imaging [6], [7], [8], [9], [10], [11], acoustic radiation force imaging (ARFI) [12], [13], [14], motion compensation for synthetic receive aperture imaging [15], phase-aberration correction [16], [17], [18], noninvasive temperature estimation [19], and so on. Time-delay estimation can be performed in different domains such as time, phase, or frequency. The time-delay estimates between two consective RF frames were computed pair-wise by dividing each

Objectives
Methods
Results
Conclusion

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.