Acoustical experiments on A-scan and B-scan using two low-frequency ultrasonic transducers

• Main Authors: Diaz, Jose Antonio S., Noel, Anna Marie F., Tang, Reynold Kenneth C., Velasquez, Ma. Luisa C.
• Format: text
• Language: English
• Published: Animo Repository 1995
• Subjects: Ultrasonic transducers; Acoustic imaging; Diagnosis, Ultrasonic; Digital electronics; Electronic digital computers > Programming; Electronic data processing; Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/9390
• Institution: De La Salle University

The thesis, Acoustical Experiments on A-Scan and B-Scan Imaging Using Two Low Frequency Ultrasonic Transducers, aims to determine the factors that affect A-scan and B-scan pulse-echo imaging in air, water and semi-solid mediums using 2 ultrasonic transducers, namely: a 50 Khz transceiver and a 40 Khz transmitter and receiver.Pulse-echo imaging is the most popular type of imaging modality in ultrasonic imaging. In this type of modality, the system transmits a short burst of ultrasonic signal and it listens for the return echoes to the system. It then measures the time-of-flight traveled by the ultrasonic signal as a function of the distance. The measured time can give both range and size information. Different mediums such as air, water and semi-solid have different acoustical impedance. Acoustical impedance is related to the density and elasticity of the medium. With respect to this characteristic, the thesis also aims to determine the limitations of each transducer in different mediums.The heart of the hardware component of the system is its Data Acquisition System. It consists mainly of an analog-to-digital converter and an interface chip. The time-of-flight of the echo is first converted to its corresponding digital value and it is then interfaced to the computer. Upon interface, the software component (using Turbo C++) will compute for the corresponding size and distance of the digital time-of-flight. The software also provides the range of values that will determine the different colors that will be used in producing a grey-scale image of the object.