University of Illinois Urbana-Champaign

Advanced Data Acquisition and Processing Systems for OCT

Prakash, Shreya

This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.

Permalink

https://hdl.handle.net/2142/46536

Description

Title
Advanced Data Acquisition and Processing Systems for OCT
Author(s)
Prakash, Shreya
Contributor(s)
Boppart, Stephen
Issue Date
2011-12
Keyword(s)
  • imaging
  • medical imaging
  • optical coherence tomography
  • data acquisition
  • data processing
Abstract
Optical coherence tomography (OCT) is an optical signal acquisition and processing method that uses near infra-red light (800 - 1300 nm) to penetrate deep into scattering media like biological tissue. It can achieve micrometer resolution (1- 10 ), which is a significant advantage over biomedical imaging modalities such as ultrasound; however, this modality provides a limited penetration depth of only 2 - 3 mm. One of the major challenges in incorporating OCT in the clinical environment is the required high data acquisition and processing speeds. Although laser sources and optics hardware exist that can acquire many thousands of A-lines per second, the major bottleneck is in the software, and many groups have found that reliably digitizing, acquiring, synchronizing and processing data at these high speeds is extremely challenging. There has been a recent surge in interest in using different platforms such as Field Programmable Gate Arrays (FPGAs), Digital Signal Processors (DSPs), and Graphical Processing Units (GPUs) to solve many of these processing problems. The main focus of this thesis is the implementation and evaluation of a fast spectral domain optical coherence tomography system that can do three-dimensional (3D) imaging in real-time, and the acquisition of raw data from a catheter-based swept source OCT system to gather phase information. In order to upgrade the OCT system in the Biophotonics Imaging Laboratory, the following changes were incorporated: inclusion of GPUs for faster processing of the image data, a faster OCT line-scan camera that provides a high scan rate, faster data acquisition (DAQ) cards along with updated drivers, and efficient software. For obtaining raw data from the commercial swept source OCT (SS-OCT) system, a different, faster DAQ card was used to acquire fringe data for A-scans. Further processing such as Fourier transformation and Cartesian to polar transformation was then used to visualize the data. The key upgrade discussed in this thesis is the development of software based on C++ in Visual Studio 2008 for the acquisition and synchronization of Fourier domain OCT (FD-OCT) and the development of a virtual instrument for acquiring data for swept source OCT based in LabVIEW for further analysis. As a result, synchronized FD-OCT waveforms were generated to capture data. For the SS-OCT system raw data was successfully gathered. This raw data can essentially be used to derive phase information. This information is useful in multiple applications such as MM-OCT, ISAM, and needle-biopsy. Hence, a faster acquiring OCT system was set up using new hardware and software. Moreover, a virtual instrument and interface was set up to retrieve magnitude and phase information in the unfiltered stage from the Lightlab Imaging System that acquires scans of non-human patients. Described in this thesis are the future applications for the two systems and the future-efforts to make the acquisitions more efficient and enable viewing in real time.
Type of Resource
text
Language
en
Permalink
http://hdl.handle.net/2142/46536

Owning Collections

Senior Theses - Electrical and Computer Engineering PRIMARY
The best of ECE undergraduate research