《基于FPGA的自动调焦电路设计与实现》-毕业论文.doc

哈尔滨工程大学本科生毕业论文 基于FPGA的自动调焦电路 设计与实现 院 （系）：信息与通信工程学院 专 业：电子信息工程 学 号： 学 生 姓 名： 指 导 教 师： 副教授 摘　　要 随着超大规模集成电路的发展以及现代光学仪器设备在智能化、简便化方面的突破，令数字光学设备迅速普及。数字信号处理理论的成熟与发展使得基于数字信号处理方式的自动调焦成为可能。 本设计使用FPGA作为数字信号处理与系统控制的核心器件。将由摄像头输入的模拟电视信号转换为数字电视信号；经过FPGA处理后再将其转换为模拟电视信号输出，并由电视机显示；同时FPGA控制电机的进退实现自动调焦。 系统硬件部分以FPGA为核心，搭载输入视频处理器SAA7111AHZ与数字视频编码器SAA7120以及RAM等其他附属电路。系统软件部分使用I2C总线实现对输入视频处理器和数字视频编码器的初始化，实现PAL制式模拟电视信号-YUV数字电视信号-PAL制式模拟电视信号的转换，并使用电视机将其输出。根据复合视频图像信号的相关原理，对输入视频的中心区域进行灰度熵值的运算，并控制电机的转动方向以阈值法实现自动调焦。 在本设计中，完成了相关的软件和硬件设计，并经过调试后，能够实现较好效果的自动调焦。 关键词：FPGA；灰度熵；输入视频处理器；数字视频编码器 Abstract The digtal optical equipments become popular,with the development of very-large-scale integrated circuits and the major breakthrough of the modern optical equipments in intelligentizating and facilitating process. The automatic focusing which based on digital signal processing can be realized. In this desgin, FPGA is the key component of digital signal processing and system control.Firstly, an analog TV signal captured by the camera is transformed to a digital TV signal; and then the digtal TV signal is processed by FPGA and finally it is transformed to an analog TV signal output; at the same time, the automatic focusing is realized by the motor controled by FPGA. In the hardware part of the system,FPGA is used as the key component,with accessory circuit such as video input processor, digital video encoder and so on.In the software part, the video input processor and digital video encoder is initialized throgh the I2C bus in order to realize the interconversion of PAL standard analog TV signals and YUV digital TV signals ,which are the output of monitor. According to the theory of composite video signal,the system selects the center part of the input video and calculates its gray region entropy , then control the motor rotation to realize automatic focusing using the thresholding method. In this design, the relevan