1. Veera Sundararaghavan At NDE Laboratory, Michigan State University Special thanks: Prof. L. Udpa, Prof. P. Ramuhalli 2002 Summer research work Development of data acquisition, signal processing and visualization software for a Portable Ultrasound thickness gauge

2. NEED To develop a manual portable ultrasound thickness gauge and a data visualization software Present sensors - Position data?? –Tee and Elbow sections ?? Gridding and measurement

3. Pulser/Receiver Flock of Birds Transmitter To A/D card Panametric P/R Receiver To Serial Port

4. Flock of Birds (FB) Sensor Pulsed DC magnetic tracking. Advantages over acoustic,optical and mechanical tracking are, –Full six degrees-of-freedom tracking without limits in angular coverage. –Small form factor. Sensors ranging from 25mm to 5mm wide for tracking even instruments inserted into the human body. –Unlimited range of motion without mechanical or line-of-sight limits. –Real time tracking of multiple sensors. Wireless sensors can now track up to 100 sensors simultaneously for real time animation of characters.

5. Applications of FB Virtual reality games Simulation - Entertainment - Motion Capture Medical 3D imaging Biomechanical measurements Scientific visualization Telerobotics

6. Functioning of FB

7. Transmitter Electronics

8. Signal processing

9. Signal timing

10. Data Acquisition Point by point acquisition using drivers written in MATLAB 6.0 & Instrumentation and DAQ Toolboxes are used STEPS: –Load bird settings (COM Port, Baud rate etc.) –Set up bird hardware by writing bytes to the serial port –Data acquisition of bird position as bytes –Convert bytes to position data –Use DH matrix to transform the coordinates –Examine bird settings..reset and close serial port when error occurs

11. Denavit-Haartenberg(DH) Matrix X S = X B + X O * M(1,1) + Y O * M(2,1) + Z O * M(3,1) Y S = Y B + X O * M(1,2) + Y O * M(2,2) + Z O * M(3,2) Z S = Z B + X O * M(1,3) + Y O * M(2,3) + Z O * M(3,3) X S,,Y S, Z S X B,,Y B, Z B 0,,0, 0 X Y Z XOXO YOYO ZOZO M = COS(Y)*COS(Z)COS(Y)*SIN(Z) -SIN(Y) -COS(X)*SIN(Z) +SIN(X)*SIN(Y)*COS(Z ) COS(X)*COS(Z) +SIN(X)*SIN(Y)*SIN(Z) SIN(X)*COS(Y ) SIN(X)*SIN(Z) +COS(X)*SIN(Y)*COS(Z ) -SIN(X)*COS(Z) +COS(X)*SIN(Y)*SIN(Z) COS(X)*COS(Y )

12. Ultrasound DAQ DAQ using Matlab DLL drivers provided by GAGE APPLIED Inc TOF measurement Low pass filtering Hilbert envelope is found Smoothing using gaussian convolution Thresholding and Peak detection Testing of results for a calibrated block

13. Software Specify Geometry Specify parameters (material,velocity of sound etc) Start/stop scan (online acquisition and imaging) Generation of a tomographic image Save data as x,y,z and TOF (not thickness??) Compare Data from previous runs

14. Software

16. Steps towards a portable device Use of multiple transmitters in order to test complex geometries Design of a mechanical fixture/Clamps in order to hold and move the transmitters Squirt devices for couplants Software : 3D Curve fitting of points to create the required surface during testing itself (instead of warping)