为了便于调试CCD成像系统以及检测系统接口的可靠性,基于CCD扫描成像原理设计了功能特点各异的几种自校图形来模拟CCD图像数据。作为数据模拟源,自校图形具有类似线阵CCD推扫成像的动态滚动特性,同时图形灰度等级变化明显,且在x和y方向上均有灰度梯度。以鉴别率图形为例,阐述了自校图形的设计思想、代码实现及仿真验证过程。设计选用VHDL编程通过现场可编程逻辑阵列(FPGA)来实现,应用TEXTIO功能通过Modelsim仿真将自校图形数据导出到文本,然后调用MATLAB读取文本并显示图形以验证设计的正确性。几个自校图形在CCD遥感相机成像系统中得到了应用,共占用了约5%的逻辑资源。应用结果显示,自校图形能及时检测出通讯和数传模块所出现的异常并能判断分析问题根源。

With the aim to debug the CCD imaging system and to detect the reliability of a system interface,several kind of self-check figures with different functions are designed to simulate the CCD image data.As image data simulation sources,these figures are characterized by their push-scanning imaging similar to a linear CCD,and have sharp gray variation in the x direction and y direction.By taking a distinguishing figure for an example,this paper describes the design ideals,code implementation and simulation procedures for these self-check figures.Moreover,a Field Programming Gate Array(FPGA) is combined with the VHDL programming language to implement the design.Then,the TEXTIO function is used to export figure data to a text through Modelsim simulation,and the text is imported into the MATLAB to show the expected figure.These figures have been applied to the imaging system of a CCD remote sensing camera,the applied results show that designed self-check figures can detect the mistakes from communication and data transmission models and can analyze the error origins.