A multi-FPGA implementation of real-time reconstruction using Total Focusing Method
Résumé
Total Focusing Method (TFM) ultrasound imaging has many advantages in terms of flexibility and accuracy in comparison with traditional imaging techniques. However, one major drawback is the high number of data acquisition and computing requirements for this imaging technique. Due to those constraints, the TFM algorithm was earlier classified in the field of post-processing tasks. Real-time imaging is a key aspect in Non Destructive Evaluation (NDE) using ultrasound techniques. In this context, fast and precise control evaluation should be implemented on a variety of pieces. This paper describes a dedicated architecture for real-time TFM imaging using the Full Matrix Capture (FMC). In the acquisition process, data are sequentially acquired from phased arrays and temporally stored in order to be processed with synthetic focusing techniques such as the TFM algorithm. The FMC-TFM architecture consists of a set of interconnected functional blocs and integrated in an embedded system. Initially, this acoustic measurement system was dedicated to the parallel data acquisition from phased arrays. The architecture was entirely described using VHDL language, synthesized and implemented on a V5FX70T Xilinx FPGA for the control part and a V5SX95T Xilinx FPGA for the acquisition part. The maximum operating frequency is 147.3 MHz for the control part and 161.3 MHz for the acquisition part. The architecture is able to perform real-time FMC-TFM imaging at a maximum frame rate of 73 frames/s and a maximum resolution of 128×128 pixels, which is sufficient as a performance for a real-time imaging with a good characterization of defects.