The Application Of Object-Oriented Technique In Digital Speckle Image Correlation Method

Digital speckle image correlation method (DSCM) is a quantized opticalexperimental method that can accurately determine two-dimensional in-planedisplacements and strains of a target surface. It's principal is that comparelycalculating two digital speckle images of original and deformed object surface to finddisplacement and strain of every point then whole field. It's advantages than othercommon optical experimental method is as following: an ordinary lamp can meet therequirement of light source, and no strict to experiment environment, furthermore it'smeasurement level and sensitivity vary a lot that can be applied in macro or microdisplacements/strains determination. With rapid development of hardware andsoftware, especially the personal computer, it overcomes the limitation ofcomputation speed, then is extensively used in many industries. The key issue of DSCM is the implement of interpolation representing the realspeckle image and the optimization algorithm finding the right solution. Anyway, wehave several choices like Matlab, Fortran, ANSI C++ even or the current popular Javaor C#. For a non-computer-expert scientific researcher, Matlab is the best choice.Because Matlab is a high-level technical computing language and interactiveenvironment for algorithm development, data visualization, data analysis, andnumerical computation. Using MATLAB, you can solve technical computingproblems faster than with traditional programming languages, such as C, C++, andFortran. Then the most powerful language C++ which is very difficult to learn butwith high peformance. It can work together with C and assembly with very fastrun-time speed. Plus is the support to Object-Oriented Technique making it the firstchoice of all most the commercial software products. While in fact we have no reasonto use Java or C# for DSCM except their popularity. The integrated developmentenvironment(IDE) is also a big issue. Borland C++ that comes later than Visual C++is more easy for graphic user interface(GUI) programming, but Visual C++ is morestable and less bugs. So we favor the later one.In practice, a not-well-organized software is like a dense mass that every part istight coupling with each other so it's hard to learn, maintain and extend. When ithappens in our research division, every time a new student involves in the project, hehave to re-design and re-write the whole software so as to continue the research. Theresult is lots of time and effort is wasted. Another problem is how a language canrepresent mathematic concept and routine very well so the researcher can focus on thealgorithm without interrupted often by computer language.To resolve all these problems the author developed most of the classes with ANSIC++ and GUI with MFC(Microsoft Foundation Class) ported together with VisualC++.Net. After a-short-time application of my software and fixing some bugs, nowthe DSCM software works very well. And in a wood joint-finger experiment, it gaveus reasonable good results.