Investigation On Digital Image Holographic Interferometry Measurement Of Liquid Mass Diffusion Coefficient And Image Processing

The image processing technology have been applied to more and more fields as well as it is developing rapidly. Digital image processing technology is developing towards high processing quality, its algorithms have been optimized, its speed have been higher, and it is ultimate objective to solve practical problems to be applied to other subjects. With the mass transfer process research in chemical engineering gradually deepened and its application field expanded, concentration distribution, diffusion coefficient and mass transfer coefficient have become the extremely important factors as well as the design and development in chemical engineering. Laser holographic interferometry method has some advantage such as non-contact measure, high sensitivity, more information, high precision and so on. Associating with this method, a measure system in mass transfer process is established based on the image processing technology.Based on a multitude of literature, the paper reviewed that the theory research technique and the experimental research technique of the diffusion coefficients, and digital image holographic interferometry was used in the measurement of liquid mass diffusion coefficients, so we employed digital image holographic interferometry measurement of liquid mass diffusion coefficients.An experimental optical system based on digital image holographic interferometry measurement of liquid mass diffusion coefficients was designed and constructed. Based on the establishment of the real-time digital image holographic interferometry measurement of liquid mass diffusion coefficients beam path experimental system, improve the quality of the digital holographic interferometry image, enhance the stability of the experimental system and improve the accuracy of the experimental system.According to characteristics of the interferograms, employing such key techniques of digital image processing as the image enhancing, the interference fringes rebuilding and the phase unwrapping to process the interferograms, and the key to the image processing is the phase unwrapping, the phase unwrapping algorithm based on the solution of discrete Poisson equation is presented in this paper, the phase difference was obtained, and therefore the mass diffusion coefficients of KCL aqueous solution was also gained by conversion.The mass diffusion coefficients of KCL aqueous solution and saccharose aqueous solution at temperature 295.15K were measured to verify the accuracy and reliability of the system by compared with the data from literature, It can be concluded that the system can provide an effective method for measuring the mass diffusion coefficient of new refrigerants, which is urgently required in chemical engineering application.