多TDICCD拼接相机在异速工作模式下,不同通道的CCD图像间会存在相互干扰现象,不同行频差会在图像上产生不同斜率、不同宽度的干扰斜条纹。为了解决此问题,文中对原设计电路系统进行了详细分析和优化设计。首先,从异速时序在不同行周期的相位差别上进行分析,异速模式下不同CCD成像电路时序间存在行频差异,导致各个行周期内CCD个别像元上与其他像元叠加的干扰不一致,是干扰斜条纹产生的原因。然后,采取优化关键信号布线方式、系统地和电源布置、去耦电容接地方式等多方面对电路系统进行了改进,优化多TDICCD成像系统电路抗异速干扰设计。最后,对改进后的电路系统进行测试,去除干扰斜纹,并将图像均方根噪声水平由21.5mV降低到4.2mV。结果表明:采用抗干扰技术,有效地去除了通道间干扰斜纹,提高了图像质量。
TDI CCD imaging There were jamming inclined circuits had been interfered by each strips whose slopes varied with raw other in multi-velocity working mode frequency on the image of that mode The original circuit design system was detailedly analyzed and optimized to solve this problem.First, the phase difference in various line cycles had been analyzed. Since there were many differences in every line cycle of various CCD imaging timing, the interference was different between some pixels and other pixels of every line in multi-velocity working mode. The interference difference of some pixels was the reason that causes jamming inclined strips. Then, those problems were solved by these methods, such as the optimized routing of critical signals, adjustment of ground and power layout, and improvement that the decoupling capacitor connected into ground. Finally, imaging circuits were tested after improvement. The results indicated that jamming inclined strips were eliminated. Image RMS noise wasreduced from 21.5 mV to 4.2 mV. The experiment showed that the use of anti-jamming technology effectively reduced the channel interference and improved image quality.