像素对图形电磁计算精度的影响和解决方法

在图形电磁计算中,通过控制图像绘制分辨率提高物理光学积分的计算精度.使用像素级的面元近似,把物理光学积分转化为具有数值积分形式的基于像素的求和.使用Nyquist 空间采样理论,提出了能够满足高频RCS(Radar Cross Section)计算精度需要的像素对应的电尺寸值;由此给出了图形电磁计算中的图像分辨率的确定准则,并提出一种改变图像分辨率的方法.通过分析典型目标和复杂目标的计算实例,这种确定图像分辨率的准则可以成立. 

Influence of pixels to graphical electromagnetic computing accuracy and its solution methods

In graphical electromagnetic computing(GRECO),the image rendering resolution was adjusted to improve the physical optics(PO) integral evaluation accuracy.In the PO integral calculation,the visible scattering surface was approximated by flat panels at the pixel level.Therefore the PO integral was evaluated numerically by using a GRECO formula which is equal to the coherent addition of the contribution from all the pixels in the target image.The electrical size of screen cell per pixel was bounded with a maximum Nyquist spatial sampling interval,thus a GRECO image resolution determination criteria which meets the precision requirement of high-frequency RCS calculation was suggested,followed by an image resolution adjusting implementation.Illustrative numerical results for a canonical and a complex targets were presented,which demonstrate the validity of the GRECO image resolution determination criteria.