Page 1 |
Save page Remove page | Previous | 1 of 134 | Next |
|
small (250x250 max)
medium (500x500 max)
large ( > 500x500)
Full Resolution
All (PDF)
|
This page
All
Subset |
HIGH-FREQUENCY ULTRASOUND LINEAR ARRAY IMAGING SYSTEM USING ANALOG BEAMFORMER
by
Lequan Zhang
A Dissertation Presented to the
FACULTY OF THE USC GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(BIOMEDICAL ENGINEERING)
August 2011
Copyright 2011 Lequan Zhang
Object Description
| Title | High-frequency ultrasound linear array imaging system using analog beamformer |
| Author | Zhang, Lequan |
| Author email | lequanzh@gmail.com;lequanzh@gmail.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Biomedical Engineering |
| School | Viterbi School of Engineering |
| Date defended/completed | 2011-04-28 |
| Date submitted | 2011-08-01 |
| Date approved | 2011-08-03 |
| Restricted until | 2011-08-03 |
| Date published | 2011-08-03 |
| Advisor (committee chair) | Shung, K. Kirk |
| Advisor (committee member) |
Yen, Jesse T. Singh, Manbir Hashemi , Hossein |
| Abstract | High-frequency (HF) ultrasound imaging, capable of achieving superior spatial resolution in real-time, has been shown to be useful for imaging and visualizing blood flow in ophthalmology, dermatology, small animal and intravascular imaging. The utilization of HF linear arrays along with beamformer for beam focusing can alleviate the limitations of the systems with single element transducers, such as single focal point, image degradation caused by mechanical and limited frame rate. This dissertation presents an investigation into the development of a high-frequency linear array ultrasound imaging system using analog beamformer. A HF high frame rate duplex system with 30 MHz 64-element linear arrays capable of fast B-mode image and pulsed-wave Doppler measurement was first implemented using high speed electronics to provide real-time duplex visualization for small animals cardiovascular activities. Subsequently a 64-channel analog beamformer was next developed in order to achieve better lateral resolution. In this design new passive delay line components can provide a total delay of 157 ns with 1ns resolution to support a 30 MHz 256-element linear array with 50 μm pitch. The transient effect caused by multiplexer switching was alleviated by using low charge injection multiplexers, differential circuits and time domain offsetting. An imaging system based on this beamformer was built by integrating it with the transmit beamformer, pulser/receiver, and a PC back-end controlling and processing unit implemented using a powerful and low-cost graphics processing unit (GPU). Both phantom and in-vitro experiments demonstrated that the system was able to achieve better resolution and clearly reveal the detail structures of the biological tissue samples such as excised bovine eye. High-frequency color flow imaging (CFI) using linear array was also investigated. In order address the challenge in high-frequency CFI, an adaptive clutter filter was proposed and the experimental results indicated that the adaptive filter could more effectively suppress the clutter signal under the high-frequency condition. The linear array system was then expanded to support real-time CFI, utilizing the programmable frond-end scanner and powerful GPU back-end processor. The parallel architecture and C language development interface of the GPU has enabled easy implementation of parallelism on the CFI algorithm. Experiment on flow phantom had shown that this prototype real-time CFI system could consistently visualize slow flow over a large field on view. |
| Keyword | beamforming; color flow imaging; GPU; linear array; small animal; ultrasound imaging; high-frequency ultrasound |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m |
| Rights | Zhang, Lequan |
| Access conditions | The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the author, as the original true and official version of the work, but does not grant the reader permission to use the work if the desired use is covered by copyright. It is the author, as rights holder, who must provide use permission if such use is covered by copyright. The original signature page accompanying the original submission of the work to the USC Libraries is retained by the USC Libraries and a copy of it may be obtained by authorized requesters contacting the repository e-mail address given. |
| Repository name | University of Southern California Digital Library |
| Repository address | USC Digital Library, University of Southern California, University Park Campus MC 7002, 106 University Village, Los Angeles, California 90089-7002, USA |
| Repository email | cisadmin@usc.edu |
| Archival file | uscthesesreloadpub_Volume71/etd-ZhangLequa-235.pdf |
Description
| Title | Page 1 |
| Full text | HIGH-FREQUENCY ULTRASOUND LINEAR ARRAY IMAGING SYSTEM USING ANALOG BEAMFORMER by Lequan Zhang A Dissertation Presented to the FACULTY OF THE USC GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (BIOMEDICAL ENGINEERING) August 2011 Copyright 2011 Lequan Zhang |
Comments
Post a Comment for Page 1
