The Research Of The Detection System Of The Three Linear Image Sensorn Based On The FPGA

Currently non-contact testing in real time, using image sensing technology for high speed and high precision, has become a reality and achieved some success. The emergence of CCD (Charge Coupled Devices) makes the machine vision inspection systems fully developed. The CCD can obtain detection effect which has advantages of high resolution, large scale, high speed in non-contact measurement. In addition, as one of the most widely used programmable logic devices resently, FPGA (Field Programmable Gate Array) has many properties such as fast operation, flexible configuration and using-easy, which make it the first choice candidates as a central control unit in image detection system. The system is consists of image sensors for the system in three-line array color CCD (Charge Coupled Devices) and a control kernel using highly integrated FPGA. The main methods and conclusions are as follows:(1) It is drived on requirements of analysis of linear array image sensor TCD2557D using the Altera’s FPGA as the centre of the control. Under the QuartusII development environment, the system is complished to sensor-driven by operating VHDL hardware description language. This method is designed to be simple, strong readability and portability, design upgrades is simple and convenient.(2) According to thecharacteristics of image sensor output signal, it is proposed to use both hardware and software to process circuit. Both methods are able to not only effectively reduce the output noise of a linear array image sensor, but also better solve the problem of sensor effective signal such as small amplitude, negative polarity, and other issues.(3) It is required to built storage system which is consists of digital-analog converter, data caching, and a high speed data acquisition based on FPGA. The maximum sampling frequency of system can reach3MSPS, sample rate and accuracy can be selected. The system can meet different types of image sensors for data acquisition and storage requirements.(4) The system can provide appropriate solutions to apply to practical applications in the detection system and eventually to get a steady detection signal and be able to detect differences in size and color differences. The result is demand to analyse the influence factors of the accuracy of the detection system for varieties of phenomenon.This system is characted with high sensitivity, fast speed, good reliability and sharp integration. The design upgrade of system is simple and convenient and the whole system is completed to use VHDL hardware description language, as the result, it have good synchronization and has the ability to achieve real-time detection.