多通道TDICCD卫星遥感相机图像噪声分析与处理

Analysis and Suppression of Imaging Noise of Multi-TDICCD Remote Sensing Camera

摘要:

为了解决多路时间延迟积分电荷耦合器件(TDICCD)拼接遥感相机成像的噪声问题,提高载荷焦面电箱的成像信噪比和成像质量,通过分析噪声现象,发现多路TDICCD成像噪声的主要原因有两个:一是多通道TDICCD未能实现同时刻开启成像,使得成像电路电源出现高频纹波噪声且多通道噪声相混叠,这样对各通道CCD模拟信号造成干扰；二是电路中的DC-DC电源开关噪声扰动影响了CCD有效视频信号的采集。从工程研制实际出发,采取CCD通道之间共用统一的系统时钟,相同系统复位等措施对多TDICCD成像电路系统进行改进,抑制通道间成像串扰的发生,通过对主要干扰源DC-DC电源进行滤波处理与TDICCD端多点接地等方式,抑制电源噪声对TDICCD成像的干扰。对改进后的多通道TDICCD成像电路系统进行成像和信噪比测试。实验结果表明,采取的措施有效地去除了TDICCD成像噪声,相机信噪比提高了2dB,且外场成像质量高,可满足实际工程的需求。

Abstract:

In order to solve the problem of imaging noise of multi-channel time delay integrated charge coupled device (TDICCD) splicing remote sensing camera, and improve the signal-to-noise ratio (SNR) and imaging quality, two main reasons for the noise of multi-TDICCD imaging were analyzed. First, the unsynchronized operation of the CCD causes the ground plane high-frequency disturbance of the power supply of the TDICCD imaging circuit, which affects the acquisition of the effective video signal of the adjacent channel CCD. Secondly, the switching noise disturbance of DC-DC power supply in the circuit affects the acquisition of CCD effective video signal. Based on the practice of engineering development, the multi-TDICCD imaging circuit system is improved by taking measures such as sharing a unified system clock and the same system reset between CCD channels to suppress the imaging crosstalk between channels. The interference of power supply noise on multi CCD imaging is suppressed by filtering the main interference source of DC-DC power supply and multi-point grounding of TDICCD port. The imaging and signal-to-noise ratio of the improved multi-channel TDICCD imaging circuit system were tested. The results show that the measures remove the imaging noise effectively and significantly improve the SNR by 2dB, and the excellent field imaging quality can meet the requirements of practical engineering.