Digital Holography And Its Measurement In Applied Research, The Structural Deformation

The structure deformation measurement is always to be the important problem of the field of the structure engineering. The traditional way of structure deformation measurement is not exact enough, and it is complex. While the optical measurement method has many good qualities such as high precision, simple facilities, changeable optical line, no damnification to the measured object, no special treatment to the surface of the measured object and so on. It has been abroad used in macroscopical fields and microcosmic fields, especially in wisp deformation measurement. Thus we tried measuring small structure deformation using the digital holography interferometry which is in the field of the optical measurement.Optical holography was proposed by Gabor in 1948. Along with the appearance and improvement of CCD and the improvement of computer technology, digital holography was proposed by Goodman in 1970s. It is a combination of traditional holography and modern electronic technology. Due to its all-digital experimental procedure, digital holography can be easily performed and transmitted with modern information technologies. Its procedure involves no chemical processing, so digital holography is much more convenient and speedy than traditional holography. Further more, it can simultaneously obtain both the intensity and profile information of a specimen with only one exposure, so it is much favorable for many practical applications. Owing to all these outstanding advantages, digital holography is regarded as a great progress in the development of modern optical measurement in mechanics and has been broadly studied.Significant progress has been made in digital holography since it was proposed in 1994. It has proved to be a powerful tool for scientific researches and has found many applications in profile measurement, deformation measurement, aberration compensation, defect detection and neutral network et al. However, almost all these researches were intended to demonstrate how to replace traditional holography with digital holography. Only few attempts at studying the characteristics of digital holography have been reported, and all research works are seriously restricted to the domains that originally belong to traditional holography. Digital holography is badly hindered from its further development.In order to make full use of digital holography, we must study all its basic characteristics systematically and detailedly, and combine it with other information processing technologies. Only to do this, can we fundamentally solve the problem which...