ACOUSTICAL IMAGING RESEARCH FOR NONDESTRUCTIVE TESTING METHODS IN FOSSIL RECOVERY
Bradley University Department of Electrical and Computer Engineering by: Matt Kaiser and John Lewis
CALL DEPTH FUNCTION
CALL CLASSIFY FUNCTION PROMPT USER TO ENTER TEMPERATURE AND MAX DATA SET
STORE VALUE IN AN ARRAY
Advised by: Dr. James H. Irwin and Mr. Jose Sanchez
BREAK THRESHOLD & WITHIN TIME LIMITS & NOT NOISE? YES
SEND BACK VARIABLES & END
CALCULATE SPEED OF SOUND
END OF DATA? YES
READ IN DATA PLOT DATA IN 3-D
Objective of Research The objective of the research is to be able to effectively image objects buried within like objects. Fossils are an excellent example of two like objects contained within each other. The goal is to do this imaging in a non-destructive manner. The same techniques can also be applied to non-destructive testing and other advanced imaging problems. Signiﬁcance of Research When trying to recover fossils or perform non-destructive testing (NDT), one makes every effort possible to not damage the tested material. In fossil recovery it is useful to obtain a picture of the fossil before attempting its recovery. This minimizes the possibility of damaging the object. It also allows the person to decide if the object in question is worth recovering.
Figure 3: Main Software Flow Chart
Figure 4: Top View of Washer Image
Visual Display Figure 1: System Block Diagram
The signal generator produces bursts of 2 [MHz] sine waves into the acoustic sensor at 10 [Hz] intervals. This causes the sensor to ring and send out an acoustic pulse. The sensor is submersed in water and the pulse is transmitted through the water. When the wave hits an object, energy is reﬂected and absorbed. The reﬂected energy returns back to the sensor, and the absorbed energy penetrates and returns another echo if one exists in the object. The returned acoustic pulses are then passed through a cascode ampliﬁer. This ampliﬁer provides high gain at high frequency. The signal is acquired using a Tektronix TDS3012B e*Scope. This oscilloscope has a built-in web server. This allows all the data to be acquired via ethernet. The data is then manipulated in MATLAB. The software analyzes the returned echoes and then constructs an image based on the echoes. These results are then outputted to the screen where the end user can view the results.
WAIT FOR 16 PULSES TO PASS
BREAK THRESHOLD & WITHIN TIME LIMITS & NOT NOISE?
Figure 7: Depth Calculation Routine
Setup 3 Classes in Time
Object in First Class?
Object in Second Class
Object in Third Class
Figure 8: Classiﬁcation Routine Figure 5: Side View of Washer Image
Figure 6: Averaged Surface Image Figure 2: Recombination of Multi-Layer Object
Figure 9: A-Scans for Washer