【作者】 朱体高；

【导师】 刘铁根； 赵永福；

【作者基本信息】 天津大学 ， 仪器仪表， 2011， 硕士

【摘要】 本文详细讲述了在CCD色选机中使用的信号处理的方法,包括系统的定位,系统的硬件设计和软件设计。其中系统的定位是为了保证信号处理的一致性和准确性,在实现的时候纵向采用纯粹的机械定位,在横向采用电辅助机械进行定位。CCD信号的处理采用CPLD与DSP相结合的方法。CCD选择的是高速线阵CCD。CPLD完成对CCD的系统时钟信号的驱动和吹气信号的脉宽延时信号的处理。在驱动CCD的时候为了提高行扫描的速度,采用了快慢结合的方法,在使用的像素点采用慢速以提高信号的质量,在不需要使用的地方采用快速以实现信号的转移。在CPLD上挂接存储器,并在存储器上实现循环的队列实现吹气信号的脉宽和延时处理。DSP选用的是TMS320DM642,它有许多外部设备,系统的资源多,功能强大,集成开发环境好,芯片运行的速度快,满足一个DSP芯片处理两个CCD镜头信号的要求。它通过集成的图像采集口采集CCD的图像信号,在处理时采用卷积平均的方法降低系统的噪声,用一阶高通滤波的方法去除直流分量。在处理的时候核心算法部分采用线性汇编语言编写,以降低代码的长度,提高代码的效率,最终提高系统的运行速度。为了使多个信号处理系统与控制系统相连接采用RS422多机通讯的连接方式,控制系统为主机,信号处理系统为从机。在通讯协议中开始和结束用特殊字符,中间的数据采用ASCII码进行区分。在传送的数据中包含有地址信息,只有主机命令的地址与实际的地址相吻合的时候才处理数据。更多还原

【Abstract】 This paper describes signal processing methods used in the CCD color sorter. It includes system position, hardware design and software design. Positioning system ensures the accuracy and consistency using in singal processing. The vertical positioning is purely mechanical positioning. The horizontal positioning is the mechanical positioning with the help of electrical auxiliary.In hardware the system uses the combination of CPLD and DSP methods to process CCD signal. In selecting CCD sensor the system uses high-speed linear CCD. CPLD functions as CCD’s system driving clock and blowing signal pulse-width and delay signal processor. In order to increase the CCD line scan frequence, CPLD adopts the method that high speed combines with low speed. When CPLD drives useful pixels it uses low speed to improve the singal quatity. On the other hand when CPLD drives useless pixels it uses high speed to transfer signal. Memory is connected to the CPLD. There is a circular queue in the memory to achieve the pulse-width and delay blowing signal processing.As to DSP, TMS320DM642 is selected. It has many peripherals and system resources. It has many powerful functions. The integrated development environment is very good. The DSP chip runs fast enough to process two CCD cameras signal. It captures CCD image signal by using the videoport integrated in the DSP. When the DSP processes the signal it uses circular average to reduce system noise.The DSP uses one stage high-pass filter to remove the DC component. When dealing with the core algorithm system uses linear assembly which reduces the length of the code, improve code efficiency and finally improve system speed.In order to connect to the control system, the RS422 standard is used for multi-computer communication. The control system is the host; the signal processing system is the slave machine. In the communication protocol it beginns and end with special characters, the middle data is the ASCII format. The data sent by host contains address information. Only the address in the host command coincides with the actual address the command has effect.更多还原