A scan conversion CMOS implementation for a portable ultrasonic system

Digital scan conversion is the process of converting received ultrasound signals (echoes) in multiscan lines, at varying angles (polar coordinate), to a Cartesian raster format for displaying. This conversion is necessary for compatibility with LCD and CRT monitors. To avoid artifacts during the conversion process the processed data are interpolated to produce the final memory image. The available interpolation methods typically require the use of two large memories, one for the interpolation and the other for the image display. In this paper, we use a simpler nearest-neighbor interpolation technique combined with the linear interpolation between adjacent scan lines to reduce artifacts on the far field. A hardware architecture is proposed that only uses a FIFO register and a memory for display. CMOSP18 technology is used to implement the described system. The proposed architecture is able to both reduce the complexity of the needed memory and increase the performance of the image processing.