嵌入式系统的制冷CCD相机(英文)

Cooling CCD camera based on embedded system

根据天文摄影中CCD的工作特性,提出了基于嵌入式技术制冷CCD相机的新方法,以ARM微处理器为硬件平台设计了嵌入式制冷CCD相机,并在低照度下的天文观测中取得了良好的效果。基于天文制冷CCD的具体特性和对信号数据输出的要求,选用CXD1267和AD9826分别设计CCD的列转移驱动时序和CCD的水平读出时序。通过微处理器定时中断,实现对CCD制冷温度的实时控制。分析了科学级CCD噪声的种类及来源,通过实验得到了温度、曝光时间与暗电流噪声的关系以及CCD的读出速率与读出噪声的关系。进而在硬件和软件上采取了相应的措施有效地降低了CCD的噪声。

A new kind of cooling CCD camera based on an embedded system was designed according to the characteristics of the astronomical camera. Using Cortex- M3 ARM as the hardware design platform, the cooling CCD camera performed excellently in the astronomical observation. CCD vertical clock driver was designed with a CXD1267 chip, and the analog signal was correlated double sampled by an AD9826 chip. The ARM chip was used for the design of CCD driver timing. Because of the timer interrupt of the microprocessor, the temperature of the CCD chip was controlled in real- time by a Peltier cooler module. Three primary kinds of noise in the presented camera system were analyzed. The influences of the working temperature and exposure time on the noise were studied in experiments. Several measures to reduce the noise of the CCD camera were discussed.