具有漏点弥补和漫游窗口的高速数字扫描变换算法

High speed digital scan converting algorithm with moiré pattern make up and roaming zoom window

为了显示现代雷达、超声检查、声纳的图象，比较了由极坐标到直角坐标的数字扫描变换器（ＤＳＣ）的各种实现方案。提出了一种单元增量计数法实现的高速数字扫描变换方案，并讨论了用新方案消除ｍｏｉｒé赝象的弥补算法及一种结合ＤＳＣ结构的漫游开窗算法。该方案可以集成于一片现场可编程门阵列（ＦＰＧＡ）中，并已应用于多种雷达数字显示系统。结果证明应用该方案可以达到５０ＭＨｚ的点变换速度，并同时完成弥补漏点和放大漫游窗口。

Digital scan converter (DSC) is an indispensable part in the display equipment of radar, biomedical ultra sound detector, sonar, electronic surface analyzer. To implement the conversion from polar coordination to Cartesian coordination, several methods such as multiplication device, accumulator, software converter based on reduced instruction structure computer have been reported in literate, but they have the limitations of high cost and low speed. A phenomenon called moiré pattern because of under sampling and truncation may be observed and it is difficult for such a DSC to open a roaming zoom window. A new DSC scheme of the increment pulses counter utilizing the serial scanning is proposed in this paper. The algorithms of making up moiré pattern and opening a zoom window are discussed. An example of radar image display DSC integrated in a field programming gate array which is based on this algorithm is presented and excellent result is observed.