Digital holography is a kind of optical information processing technology with digital method. It is a combination of traditional holography and modern electronic technology. By the way of recording ...and processing the holographic image by digital method, it is not adopted the traditional holographic photographic way of chemical processing, so that the processing is simplified. It is also convenient to improve the quality of the image and to extract the needed information by digital image processing. In this paper, charged coupled device (CCD) has been applied to holographic interferometry combined with electrical addressable liquid crystal display (EALCD), which adds new content and method to the development and application of holography. On the basis of theory analysis, a new method that combined image plane hologram with double-exposure holographic interferometry, and combined CCD with EALCD is used in three dimensional deformation measurements. This method has been improved feasible by optical experiment.
On the 12th May 2008, an earthquake with 8.0 Ms shook a large area of the Sichuan Province in China. The epicenter of the devastating earthquake was located in Wenchuan, 80 kilometers west-northwest ...of Chengdu, the capital of Sichuan Province. A lot of scholars have used various remote sensing images and other techniques to detect the disaster. Differential synthetic aperture radar interferometry (D-InSAR) is an advanced technique for monitoring large-scale terrain deformation with mm accuracy. This paper described the application of two-pass D-InSAR in mapping the co-seismic surface deformation caused by the Wenchuan earthquake including the interferometric data processing workflow and results. Chengdu region's deformation measures at roughly 140 mm in our study, which is relative rather than absolute. DInSAR applied to a terrain deformation measurement has been proven as an effective tool to detect displacements.
Introduction Michael A., Michael A.; Orteu, Jean-José; Schreier, Hubert W.
Image Correlation for Shape, Motion and Deformation Measurements,
02/2009
Book Chapter
As used in this article, the term "digital image correlation" refers to the class of non-contacting methods that acquire images of an object, store images in digital form and perform image analysis ...to extract full-field shape, deformation and/or motion measurements. Digital image registration (i.e. matching) has been performed with many types of object-based patterns, including lines, grids, dots and random arrays. One of the most commonly used approaches employs random patterns and compares sub-regions throughout the image to obtain a full-field of measurements. The patterns may occur on solid surfaces or may be a collection of particles in a fluid medium.
In view of the new observation technology of a tunnel concrete lining behavior, several optical fiber sensors were installed on the surface of the actual size loading test specimen of a concrete, ...which simulates a tunnel concrete lining, to measure the deformation of the specimen. The relationship between the behavior of the concrete specimen and the sensor location or sensor length was studied to investigate an applicability of the sensors for measurement of a concrete lining. It was concluded that optical fiber sensors can be one of the long term observation systems of a tunnel concrete lining behavior.
In order to measure the resulting deformation due to gamma irradiation of polymers, a new optical technique, namely speckle-photography, was established and used. Thin films of tetrafluroethene, with ...constant thickness were irradiated by different doses of gamma rays and the diffraction patterns of a laser beam passing through these films were recorded using the speckle photography technique. This technique has been applied to detect the radiation deformation in (Teflon) TFE, which is a crystalline polymer. A diffraction pattern due to the TFE thin layer is obtained and superimposed on the interference pattern displaying the speckle pattern pairs recorded on the same emulsion. The intensity of the obtained diffraction pattern was found to decrease by increasing the radiation dose from 5 to 12 Mrad from a Cobalt-60 source, and it vanishes at 12 Mrad dose. This may be attributed to the decrease in the degree of crystallinity of the TFE polymer with increasing radiation dose.
A camera is typically an opto-electronic device consisting of several sub-systems. First is the optics, consisting of elements such as a series of lenses, optical filters and shuttering elements that ...collect light from the object and focus the image onto the sensor plane. Second is the camera hardware. For example, when using a charge coupled device (CCD) camera to acquire digital images, the incident illumination is converted into an electrical signal. The third component (which may be an integrated element in the hardware) is the digitization and storage process. Using an A/D device, the CCD signal is converted into an array of discrete digital intensity data. In this section, we apply the pinhole projection models from Chapter 2 and develop a formulation that includes (a) rigid body transformations between several coordinate systems used to represent various elements in the imaging process, (b) the transformation between image plane coordinates and skewed sensor coordinates and (c) the effect of distortion on image positions.
In-Plane Measurements Michael A., Michael A.; Orteu, Jean-José; Schreier, Hubert W.
Image Correlation for Shape, Motion and Deformation Measurements,
02/2009
Book Chapter
Two-dimensional deformation and motion measurements were the foundation of the early applications in digital image correlation for solid mechanics measurements. In all cases, a nominally flat ...specimen (with or without a geometric discontinuity) was imaged while being subjected to nominally tensile loading. Throughout the loading process, it was assumed that the specimen deformed within the original planar specimen surface.
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