Dissertation > Excellent graduate degree dissertation topics show

Doppler spectral domain optical coherence tomography imaging algorithm research

Author: HuangLiangMin
Tutor: DingZhiHua
School: Zhejiang University
Course: Optical Engineering
Keywords: Spectral domain Doppler optical coherence tomography Cross-correlation method Higher order cross-correlation method Signal-to-noise ratio Optimization on scanning pattern
CLC: TP391.41
Type: Master's thesis
Year: 2012
Downloads: 88
Quote: 0
Read: Download Dissertation

Abstract


Optical coherence tomography (OCT) provides high-resolution cross-sectional images of tissues noninvasively. Combined with Doppler technique, it can measure the flow velocity in tissues, and has important clinical applications due to its noninvasive nature and high spatial resolution. In this dissertation, the work is mainly focused on the research about Spectral domain Doppler OCT algorithms which will improve the accuracy of the measurement. The main contents are as follows:1. Spectral domain Doppler OCT system has been theoretically studied, and the comparison of Phase-resolved method and Joint Spectral and Time domain optical coherence tomography has been shown.2. A method based cross-correlation technique was proposed to acquire and analyse the information about flow velocity with low signal-to-noise ratio (SNR) in Spectral domain OCT. In this method, we cross correlate the adjacent B-lines to suppress the noise which is uncorrelated, thus render an improvement on accuracy. We theoretically studied the procedure of this method, and analysed the correlation between the noises by computer simulation and experiment. The Doppler flow images reconstructed by cross-correlation method were compared with those reconstructed by Joint spectral and time-domain optical coherence tomography (STD-OCT). The results demonstrate that cross-correlation method can significantly suppress the noise under low SNR.3. Higher order cross-correlation method was proposed to further improve the noise suppression based on cross-correlation method. The method is theoretically developed and validated by measurement of moving mirror with known velocities. Standard deviations (STD) of flow velocities of the mirror under different SNRs are determined by the proposed method and compared with those by the modified phase-resolved method. Measurement of flowing particles within glass capillary is also conducted, and Doppler flow velocity maps of glass capillary are reconstructed by both methods. All experimental results demonstrate that the proposed method can significantly suppress noise, thus rendering it suitable for flow measurement under low SNR cases.4. A probe which is capable of two dimensional scanning based on the asymmetry fiber cantilever driven by single piezo bender actuator has been developed for endoscopic optical coherence tomography. However. Lissajous pattern realized by driving signal of sine form is hard to balance between uniformity, coverage and frame frequency, and hence hinders for optimization on scanning pattern. Based on response characteristic of the asymmetry fiber cantilever, the paper presents an amplitude modulated sine function as the driving signal for optimization of the scanning pattern. Simulations on scanning patterns under the same frame rate based on different driving signals are conducted, and evaluations in terms of uniformity and coverage are given. The comparative experiment was conducted too, and the results demonstrated the feasibility of this method.

Related Dissertations

  1. Research on Power Control Algorithm in CDMA Mobile Communication System,TN929.533
  2. 60 GHz Millimeter-wave Wireless Communication System : Modulation and Capacity Research,TN92
  3. Experimental Study on Laser Ranging with Time-Correlated Single Photon Counting Techniques,TN247
  4. The Optical Time Domain Measurement by Using Photon Counting Technology,O413
  5. Design and Optimization of Encoder and Decoder of Turbo Code Based on 802.16d/e Standards,TN925.93
  6. The Research of Wireless Channel Model in Telemeter System and Parameters Estimation of Signal,TP873
  7. Research of Quantitative T2 Mapping at Low Field Mr System,R445.2
  8. Packet Loss Recovering Technology for Speech Transmission over Network,TN912.3
  9. GPS RF Front End Design and Research of GPS Signal Acquisition Method,P228.4
  10. Improvement of DOFS Performance with Simplexs Coding,TP212.14
  11. Research on Frequency Deviation Estimation Algorithm Based on FFT,V443.1
  12. Research and Implementation on HF Technology in Strong Single-frequency-interference under the Condition of Extremely Low SNR,TN911.4
  13. Scalable Stereoscopic Video Compression Based on H.264 MVC,TN919.81
  14. Research on Distributed Aperture Target Detection Technology,TP274.4
  15. The Electromagnetic Compatibility Research between WiMAX and TD-SCDMA Communication Systems,TN929.5
  16. Research of Bin-divisible Method and Evaluating Techniques for High Density Seismic Data,P631.4
  17. Noises in Relic Gravitational Wave Detecting Experiment,O412.1
  18. Technical Research Based on Multi-domain Noise Elimination,P631.4
  19. The Research of Deconvolution Based on Signal Fidelity,P631.4
  20. The Research and Implementation of PN-Code Capture in the Low-SNR Enviornment,TN914.42
  21. Researches on Algorithms and Applications of Blind Signal Separation,TN911.7

CLC: > Industrial Technology > Automation technology,computer technology > Computing technology,computer technology > Computer applications > Information processing (information processing) > Pattern Recognition and devices > Image recognition device
© 2012 www.DissertationTopic.Net  Mobile