Research On The Problem Of Data Processing With Video Image In The Strain Test

Along with the measuring technology's development, many new measuring methods appear in succession, and among them include the digital video image measuring technology.In the procession of the measure with video image,the problem of data processing is an another diffculty. This topic refers to some solutions to this diffculty;it designs some software arithmetic and the operating interface to suit the measure with video image,and analyses and summarises the data error which appears in the measuring proccess.This text mainly is divided into six section, elaborate the data processing methods with video image respectively, and among them emphasize to introduce the adoption of digital filter technology, and its function on this topic, the underneath introduces them respectively:1. The measure technology with video image's theoretical analysis in the strain experiment process.In actual measuring process, the distance among illuminating system, vidicon and the measured body takes a great effect on the expriment result.In order to adjust the relation among them to make CCD the most sensitive,the theretical formulas among them is deduced;in the measuring process,the light energy'changing also takes effect on the measure,and the reason of this changing's appearance is also theretical deduced.2. The measure technology's system structure with video image.This measure system mainly consists of hardware system and software system, between them, the hardware system includes CCD ,lens, optical lighting system, frame grabbers and PC.For some problems which appear in the actualmeasuring process,it analyses and summarises the different parts,and choose the best conbination, of course, considering the cost mainly;the structuring diagram between the hardware is figure 1:The software system plays the key part of the whole system's working smoonthly,as it is the real-time measure,the software system is divided into six parts , including the real-time image showing part,the real-time measured data showing part,the real-time curve drawing part,the image adjusting and masking part,the image and data storing part and the data processing part.Each of them is restricted,and the data processing part is the foundation of the other five part,the relative diagram among them is figure2:3. The achievement of some arithmetics in the measuring strain process. In the application of the measuring strain with video image technology,and the cost is important.It is the best to attain the high accuracy using the lower cost of the hardware.So the sofeware arithmetic is getting more important.It includes the subpixel arithmetic's choice and the data processing arithmetic;this topic chooses three typical subpixel arithmetic among them,and compares the actual measure using the three arithmetics,and concludes the most viable arithmetics;in the meanwhile,in the data processing,we choose the Bezier curve.4. The use of digital filter technologyThe digital filter technology is the essential to the signal processing,and in the actual work of the measuring system,as it is the optical accurate measure,a lot of vibrations are exist.The topic analyses the different vibrations from the theories firstly,then,it designed different filter to carry on the filtering expriment,and amongthem choose the simulating filter;As the use of the filter,it improves the measuring system's accuracy effectivly.5. ConclusionThe measuring error is invetable in the measuring system. This topic analyses the sources of the measuring errors which exist in the system in detail,and get the best exprimental condition which suit this measuring system.The text elaborates the problems which appear in the measuring system respectivly under the different emperimental conditions,and it proves that the hardware and software arithmetics which are used in the system are viable by a lot of experiments and theories.