Reconstruction ofAreaDistance Profiles of Rigid Conduits Using 重建区距离谱的刚性导管使用.pptVIP

Reconstruction of Area-Distance Profiles of Rigid Conduits Using the Ware-Aki Algorithm By: Ramón M. Robles Irizarry Advisor: Dr. Eduardo J. Juan Outline Introduction Objectives Acoustic Principles Experimental Setup System Impulse Response Ware-Aki Algorithm Conclusion Questions Introduction Time-Domain Acoustic Reflectometry is used to determine the dimensions and compositions of an unknown object. Objectives Implement the Ware-Aki algorithm to estimate the area vs. distance profiles of a series of air-filled, rigid walled tube configurations. Explore the potential use of this algorithm to reconstruct area vs. distance profiles in liquid-filled tubes (such as blood vessels) having yielding walls. Acoustic Principles Reflections are caused by changes in impedance. The systems impedance is affected by changes in cross-sectional area. c = wave propagation velocity in m/s ρ0= density of the medium in kg/m3 S= cross-sectional area of the tube in m2 Experimental Setup Experimental Setup Impulse Response The system to be analyzed consists of rigid tubes with different cross-sectional area. The frequency response H(f) of the system is estimated using: X(f)= Incident pulse in frequency domain Y(f)= Reflection pulses in frequency domain Implementing the Ware Aki algorithm in H(t)= FFT-1(H(f)) we will obtain the area vs. distance profile of the interconnected tubes. Impulse response Pulses Captured Incident Pulse Reflection Pulses Impulse Response Ware-Aki Algorithm Originally developed for application in seismography. Recently applied to the investigations of tubes with varying cross-sectional areas. Medical Musical instruments Leak Detection etc. Object is divided into cylinders of length L, each representing an impedance Z. Lossless propagation and planar wave propagation is assumed. Ware-Aki AlgorithmInverse problem Impulse Response (simulated) Area-Distance ProfileReflection Coefficients(simulated) Impulse Response(Experimental) Are