Implementation of high frame rate digital scan converter for high frequency ultrasound mechanical sector scanner

This paper presents high speed digital scan converter (DSC) capable of providing more than 100 images per second for the cardiac imaging of the mouse where the heart rate is 3-5 beats per second. To achieve the desired performance, the developed DSC adopted linear interpolation algorithm to minimize the time consumption of fetching stored samples to carry out data interpolation and look-up table method for coordinate transformation. The imaging system can generate more than 100 images per second: scan conversion for an image pixel spends 3 clock cycles and data transfer rate between DSC and a personal computer (PC) to display the scan converted images on a monitor is more than 266 Mbytes per second. The designed imaging system was implemented by using a single FPGA (Stratix EP1S60F1020C6, Altera Corporation, San Jose, CA) and software programs written by C++. By experiment, it is shown that the implemented system is capable of acquiring up to 190 images per second. The display rate of the images is currently 80 images per second due to the limitation of a monitor's capability although all scan converted images can be stored in the hard disk of PC.