The Research And Design Of Printing Plate Mesh Point Area Rate Detection Based On ARM System

With the development of people's living standard, there are more requirements for a kind of printed matter which with a high quality and diversification. So, there is a problem which the print companies are affronted, that is, how to assess the quality of the printed matter more quickly and exactly. The traditional method is to detect the quality of the surface of the printed matter artificially which is too easy to be affected by other objective factors, so that it is hard to ensure to achieve the tasks. Now, with the development of computer hardware and software technique, it is available to detect the quality of the surface of the printed matter automatically with the technology of digital image process and machine vision.Nowadays, the embedded system has been developed rapidly, and its cost has also been reduced. Embedded system has some obvious characters as a device which is used to control or monitor machines and equipments.(1) Tailoring.It is a opening and retractility system.(2) Hard real-time. The embedded system has a rigid requirement about time. It is required to use a real-time operation system(RTOS)which can be used in various equipment controls to ensure programs be executed real-timely and reliably. (3) Unitive interface. It has a unitive interface to all equipments. (4) Easy to use. It provides a hard network function, support TCP/IP protocol and other protocols. It also provide a unitive MAC access layer interface to TCP/UDP/IP/PPP protocol, and spare interfaces to varies mobile computing devices. (5) Strong stability and wake interaction. Once the embedded system has been operated, we can't do much interference on it. So, the system which in charge of the hole system must be stability. The embedded system dosen't offer the operation command in the user interface, it offer service to the user program through the transfer command of the system.(6) Solidified code. In the embedded system, the embedded system and application software are solidified in the ROM. (7) Better adaptability of hardware.The printed matter density detection system is based on the technique of digital image collection and digital image process. With the development of optical lens, CCD equipments and CMOS image sensors, and the improve of all kinds of algorithms in the digital image process field; digital image detection technique has been widely used. In many fields, the application of digital image detection technique has hugely improved the accuracy and stability of the detection system. It enhance the rapid of detection, and reduce the un- accuracy of the detection. Nowadays, the process speed of the embedded processor has satisfy the requirement of the digital image detection technique. Therefore, the digital image detection system which is based on the digital image process technique has been widely developed. The improvement of printed matter density detection used digital image process technique is a certain trend. Above all, we start the research of Printing plate mesh point area rate detection which is based on ARM system.This paper discusses the design of the printing plate mesh point area rate detection which is based on ARM embedded system, and uses ARM9 chip and USB camera as the hardware platform. After the selection of hardware platform, we design the circuit of the embedded printed matter density detection system which is based on S3C2440A. It concludes a memory equipment circuit, a communications interface circuit which is integrant for debugging, a LCD interface circuit and a USB interface circuit which is of most essential.The emphases of the paper is to discusses the two transmission formats (BMP and JPEG) of the USB camera, the method that the USB camera is driver and loaded under the Linux system, and the application of the video capture technology (V4L) under Linux system. Ultimately, we achieve the purpose of loading the type ZC301 USB camera under the hardware platform we designed, using V4L to capture the image transferred from the USB camera, and saving the data of the images which are captured. This paper has made a detailed introduce of the hardware structure of the system, the theory of optic system, the selection and application of the camera, the technology of digital image process , and the structure and application of the V4L video capture function library.The computer image processing is the procedure that some given pictures are transformed in order to get sharp image. First, the study of object must be split from the image, then feature extraction is carried on. The characteristic of image is the property which can be as mark in image field. It has many shapes. But it can be divided image statistical and vision property generally. The characteristic of image statistical is some artificial property and could be get through by transformation, for instance, image histogram, moment, and frequency spectrum, etc.. The vision property is the nature property which can be felt directly by human vision, for instance, the area luminance, texture and profile, etc.. That the procedure of which the image is decomposed into a series of meaningful goal or area by these two kinds of properties is defined as image segmentation.After making threshold segmentation, noise removing and scan the image of the collected image samples, we select a group of data to calibrate the system. Then we come to a conclusion: it is available for the method of printing plate mesh point area rate detection which is based on ARM system. Ultimately, we analyze the data from both sides of the results of the experiment and the hardware and software of the system. And we also conclude the reasons which may case tolerance errors.