模板方法消除FY-2辐射计可见杂散光

风云二号辐射计的可见光通道图像受到由折镜进入的一级漏射杂散光的影响,仅仅依靠光机设计已经无法完全消除.为改善图像质量提出采用图像处理方法消除杂散光.在光机建模的基础上,确定出辐射计不同工作状态的直射漏光区域分布,并变换到图像坐标系.通过理论计算确定了单像元信杂比,作为漏光模板能量系数的依据.以卷积的方法来模拟一级杂散光的叠加过程,据此原理处理了正午时刻的卫星图像.结果表明,图像主观视觉效果明显改善,检查处理前后的对比度、熵值和MTF,发现此消杂过程在改善图像质量的同时不会对有用信号产生副作用.

Suppressing FY-2 Radiometer Visible Channel Stray Light by Templates

The visible channel image of FY-2 Radiometer has suffered from straight shot of stray light entered from the folding mirror,which can not be entirely removed by the improve of instrument design.To suppressing this contamination,a digital image processing has been proposed.The pathway of that stray light has been analytically established at any working status based on the structural parameter of this instrument,and then those straight shot region, called templates,have been transformed to the image coordinates.The single pixel signal stray ratio (SSR) has been calculated by theory and then calibrated to suit for the real phenomenon.Convolution of the real image and those templates has been proposed to simulate the contamination of straight shot stray light.So the deconvolution of acquired image and templates at noon has been processed then the visual effect,contrast,entropy and MTF of those processed images have greatly improved while the signal will not be degraded.