This paper proposes a full-field pulse-echo ultrasonic propagation imaging (FF-PE-UPI) system for non-destructive
evaluation of structural defects. The system works by detection of bulk waves that travel through the thickness of a
specimen. This is achieved by joining the laser beams for the ultrasonic wave generation and sensing. This enables
accurate and clear damage assessment and defect localization in the thickness with minimum signal processing since
bulk waves are less susceptible to dispersion during short propagation through the thickness. The system consists of a Qswitched
laser for generating the aforementioned waves, a laser Doppler vibrometer (LDV) for sensing, optical elements
to combine the generating and sensing laser beams, a dual-axis automated translation stage for raster scanning of the
specimen and a digitizer to record the signals. A graphical user interface (GUI) is developed to control all the individual
blocks of the system. Additionally, the software also manages signal acquisition, processing, and display. The GUI is
created in C++ using the QT framework. In view of the requirements posed by the Korean Air Force(KAF), the system is
designed to be compact and portable to allow for in situ inspection of a selected area of a larger structure such as radome
or rudder of an aircraft. The GUI is designed with a minimalistic approach to promote usability and adaptability while
masking the intricacies of actual system operation. Through the use of multithreading the software is able to show the
results while a specimen is still being scanned. This is achieved by real-time and concurrent acquisition, processing, and
display of ultrasonic signal of the latest scan point in the scan area.
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