Parametric study on resolution achieved using FMC-TFM-based phased array ultrasonic imaging

Full Matrix Capture-Total Focusing Method (FMC-TFM) is an advanced mode offered by phased array technology for defect detection and characterization. Imaging using the FMC-TFM provides simultaneous focusing at all the depths and also offers various modes of imaging by post-processing the same acquired data. In FMC, each element acts as a transmitter, and all elements act as receivers. The TFM involves the extraction of the maximum amount of possible information from the specimen. The present work aims to study the influence of various parameters such as aperture size, frequency, and depth of the defects on resolution achieved using the FMC-TFM technique. The experimental results of FMC-TFM have been compared with those of Synthetic Focusing using Linear Array (SFLA) technique, which is similar to the conventional Synthetic Aperture Focusing Technique (SAFT) in which a single element is utilized for both transmission and reception. The study revealed that the lateral resolution decreases with increase in the defect depth, decrease in the wave frequency, and decrease in the aperture size.