Design Of Diameter Measurement System Based On Cortex-A9 And Linear CCD

In the production of wire rod and pipe materials,the outer diameter is an important indicator of quality control.With the development of domestic production technology,the production speed of automated production lines has been greatly improved.Therefore,higher requirements are imposed on the outer diameter measurement technology,which requires the measurement equipment to be able to perform multi-angle automated measurement of the outer diameter of the product in real time,quickly and stably.Based on the research of embedded technology and linear array CCD application technology,this thesis designs a non-contact real-time diameter measurement system based on cortex-A9 and linear array CCD.This system is mainly used for nondestructive online measurement of various pipe outer diameters to improve the measurement speed and ensure product quality.The diameter measurement system designed in this thesis adopts a modular design and mainly includes two parts: the data acquisition part of the lower system and the data processing part of the upper system.(1)When designing the data acquisition part of the lower system,the temporal property of the CCD were analyzed first,then multiple CCD driving methods were compared,and finally the FPGA driving scheme was selected.Utilize the abundant digital logic resources inside FPGA device to realize the design of CCD driving schedule,and obtain strict timing waveforms.At the same time,control the AD chip to convert the output signal,use the gradient method to quickly locate the boundary pixel coordinates,and extract the left and right edge pixels of the object to be projected on the CCD,and develop a communication protocol to upload.(2)The data processing part of the upper system designs its hardware circuit based on the S5P4418 processor,including the power supply module,external interface module,display module,etc.In terms of software,the Linux operating system was transplanted,and the upper system application program was written using Qt language,which realized the reception,calculation,out-of-tolerance alarm and local storage of measurement data.The data transmission between the upper system and the lower system through the serial port,the upper system can be connected to up to four lower systems for simultaneous measurement.The user can set the application program according to actual needs,can choose a single lens single channel,dual channel,four channels and dual lens single channel,dual channel and other measurement modes.The diameter measurement system based on cortex-a9 and linear array CCD designed in this paper is flexible and quick to deploy,and friendly to human-computer interaction.The number of measurement channels and the measurement range can be flexibly configured according to the actual application measurement scenario,and non-contact measurement can be achieved to avoid wear on the probe and the measured object.It has high measurement accuracy and measurement speed,and this design system has application value in real-time outer diameter measurement in the production line.