Design Of Image Acquisition System Based On FPGA And Cortex-M4

With the rapid development of electronic technology and multimedia technology, miniature and professional image communication products is widely demanded, especially in the fields of consumer electronics, network communications, video surveillance, and industrial control. Image acquisition as the basis of image processing system, its effect is important on the image processing system, a lot of image processing system whit strong real-time, fast processing, and high-capacity storage, is very strict on the properties of image acquisition system, even require image acquisition system has the ability of image preprocessing. Therefore, it is an urgent need to study for high-performance image acquisition system.In view of the demand of image acquisition system, a image acquisition system based on FPGA and Cortex-M4 is proposed. FPGA is the main control chip of the image acquisition system, by building OV7670 controller, SDRAM controller, and VGA controller, to acquisition image data, storage and display; Cortex-M4 processor is the auxiliary processing chip of the image acquisition system, by controlling the Ethernet module connected to PC, realize the function of image data output. Meanwhile, Cortex-M4 processor is responsible for the extension of the system, realize all kins of communication protocols and small-capacity storage.This system consist of OV7670 sensor module, SDRAM storage module, VGA display module, Ethernet transmission module and the main control module composed of FPGA and Cortex-M4. OV7670 image sensor is used to obtain image data, and improve the system integration level; SDRAM memory as the storage unit of the system, to storage image data with high speed and large capacity; choose the VGA standard as display interface, which is widely used, enhance the system’s usability and human-computer interaction ability; and FPGA control each function module, according to the different requirements to complete reconstruction design, improve the scalability of the system; W5300 Ethernet chip is used to realize the function of Ethernet interface, Cortex-M4 processor control Ethernet transmission module, to realize the Ethernet communication. This paper introduces the main control module design and each function module design of this system, focusing on various controller built by FPGA. OV7670 controller configuration OV7670 image sensor’s internal registers by SCCB protocol, to obtain the original image data; SDRAM controller realize image data storage by producing SDRAM read and write timing; VGA controller producing the VGA display timing, and control image data to be read, to realize the VGA display of the image data; FSMC interface control module realize image data communication between FPGA and Cortex-M4 processor by parsing FSMC bus.This system integrates image data obtain, acquisition, storage, processing, display and transmission in a body, the display resolution of image data is 640×480×60 Hz, the acquisition speed is 30 frames per second, and storage capacity is 64 Mbits. This design has strong real-time, fast processing, as well as good extension ability, can be applied to different fields, and provides the basis for further research of high-performance image processing system.