Applying Coherence Factor to Double-Stage Delay Multiply and Sum Beamforming in Medical Ultrasound Imaging

The Filtered Delay Multiply and Sum (F-DMAS) beamforming algorithm has recently been proposed to improve the resolution and contrast in ultrasound imaging. Based on F-DMAS, some researchers have introduced an alternative named Double-Stage Delay Multiply and Sum (DS-DMAS), which can be considered as an enhanced version of F-DMAS. The DS-DMAS expands the DMAS algorithm to synthesize some new signals, which are then beamformed using a DMAS beamformer. However, the way to generate new signals in DS-DMAS can be thought of as a Delay and Sum (DAS) operation. There are some shortages in the DAS algorithm, so we proposed a new approach named Coherence Factor based Double-Stage Delay Multiply and Sum (DSDMAS-CF) to address these issues. The key idea of our method is to optimize the DAS operation in DSDMAS. Therefore, a modified coherence factor (CF) is applied to weight each item in DS-DMAS. The simulation, experimental and in vivo data are used to compare the performance between DAS, F-DMAS, DS-DMAS and DS-DMAS-CF. The results show that the DS-DMAS-CF gets better resolution and contrast in comparison with the other three algorithms.