A sub-nyquist ultrasound imager with subarray beamforming
Abstract/Contents
- Abstract
- Ultrasound is a popular imaging modality today. In the medical community, it is commonly used for a wide variety of applications, including early-stage cancer detection and gallstone detection. When compared to other imaging methods such as X-ray or MRI, ultrasound is safe, fast, noninvasive, and low-cost. Traditional ultrasound imagers suffer from high data rates between their sensors and their digital processing back end. This seemingly fundamental data rate is caused both by the use of many analog-to-digital converters (ADCs), each of which samples at a rate corresponding to a traditional interpretation of the Shannon-Nyquist sampling theorem. These data rates can often exceed 4 GB/s (128 sensor elements with 12 bit sampling at 20 MS/s). These data rates hold back the development of fully integrated imagers with high transducer element counts, such as 2D imaging arrays. In a departure from traditional imager design, I sample received ultrasound signals at rates below their physical bandwidth, leveraging compressive sensing (CS) techniques for digital reconstruction. These techniques allow us to reduce data rate on a per-ADC basis. I additionally introduce a mixer-based subarray beamforming technique which exploits the narrowband nature of the receiver to reduce the required number of data converters. Reducing the number of digitizers results in a multiplicative reduction in aggregate data rate. These techniques are demonstrated with a 32- channel ultrasound receiver in a PCB-based hardware implementation which reduces aggregate data rates by a factor of 50 times when compared to a conventional ultrasound topology. There exists a tradeoff between the accuracy of the reconstructed image and the fraction of the bandwidth sampled; we evaluate this tradeoff using experimental data.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2016 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Spaulding, Jonathon |
|---|---|
| Associated with | Stanford University, Department of Electrical Engineering. |
| Primary advisor | Murmann, Boris |
| Thesis advisor | Murmann, Boris |
| Thesis advisor | Arbabian, Amin |
| Thesis advisor | Lee, Thomas H, 1959- |
| Advisor | Arbabian, Amin |
| Advisor | Lee, Thomas H, 1959- |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Jonathon Spaulding. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2016. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2016 by Jonathon David Spaulding
- License
- This work is licensed under a Creative Commons Attribution 3.0 Unported license (CC BY).
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