The Measurement System Of The Linear CCD Parameters

CCD (Charge Coupled Device) is an image sensor based on photoelectric conversion. Owning its good performance, it has been widely applied these years. CCD can be classified into two groups: the linear CCD and the area CCD. The linear CCD is applied for the analysis of the spectrum and the measurement of mini-parameters; the area CCD is applied for image processing. There are many photoelectric parameters which can be used to evaluate the performance and then determine the application area of CCD.The measurement system of the linear CCD parameters is applied for measuring the photoelectric parameters of the linear CCD to evaluate its performance furthermore. As the parameters and the applications are different, the structure and the implement method of the system are diverse. Basing on the working principle of CCD, a simple measurement system of the linear CCD parameters applied for experiment and teaching is designed in this paper; the responding testing methods are given according to the definitions of the parameters as well.In hardware, the system can be divided into several parts, includes: LED light source and its auxiliary equipment; CCD and its driver circuit; the data processing circuit; the USB interface circuit. Accordingly, the tasks of the hardware design include: the design of the LED light source; the selection of the chips; the design of the CCD driver, amplifier, filter, A/D converter, memory and the USB interface circuit; schematics design and PCB layout. In software, the system includes three parts: the CCD driver program; the USB interface program; the PC interface and data processing program. The software design tasks include: using Verilog to develop CCD driver program under Xilinx ISE7.1 environment, and simulating it in ModelSim5.5 environment; useing Keil C to develop the USB firmware program Medwin environment, and using the third-party development tools to develop the USB driver program; using VC++ to develop the PC interface and the data process program under Visual C++6.0 environment.The system can measure seven photoelectric parameters: the responsibility, non-linearity characteristic, spectral responsibility, dark-signal voltage, saturate voltage, saturate exposure and dynamic rang; and there are several adjustable parameters available for observing the variation of the CCD photoelectric parameters. It is simple in structure, convenient to operate, low cost, easy to maintain and suitable for experiment and teaching.