Topic
Digital image correlation
About: Digital image correlation is a research topic. Over the lifetime, 7842 publications have been published within this topic receiving 132166 citations.
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24 Apr 2001
TL;DR: The two-photon image correlation spectroscopy (ICS) as mentioned in this paper was developed as an imaging analog of FCS optimized for measuring the aggregation state of fluorescently labeled macromolecules on the surface of biological cells.
Abstract: Image correlation spectroscopy (ICS) was developed as an imaging analog of fluorescence correlation spectroscopy (FCS) optimized for measuring the aggregation state of fluorescently labeled macromolecules on the surface of biological cells Ics was first implemented on a confocal laser scanning microscope (CLSM) and entails spatial autocorrelation analysis of fluorescence fluctuations within an image sampled from an area of the cell Spatial and temporal autocorrelation analysis of image time series enables measurement of both the molecular dynamics and aggregation state of the imaged molecules The parallel nature inherent in the collection of multiple fluctuations in an imaging scheme improves the signal to noise ratio of the correlation analysis, which enhances dynamic measurements for slowly moving species in membrane systems We outline our development of two-photon ICS and describe recent applications of the method for measurements of flow, diffusion and aggregation behavior of green fluorescent protein/integrin receptor constructs in living cells We also describe the use of two-photon excitation to perform two-color image cross-correlation spectroscopy to measure the dynamics and colocalization of non-identical species labeled with different fluorophores
42 citations
TL;DR: In this article, a non-parametric method to identify the stress field is presented, based on a force measurement on the specimen boundary and a displacement (strain) field measurement carried out by a digital image correlation technique.
42 citations
TL;DR: In this article, the effect of strain rate on the tensile properties of 6061-T6 aluminum alloy welds obtained by a novel welding method called the modified indirect electric arc technique was investigated.
42 citations
07 Aug 2006
TL;DR: In this paper, the efficiency of a random speckle pattern and its influence on the measured in-plane displacements with respect to the subset size was studied, and it was shown that the size of the speckles combined with a given pixel subset, clearly influences the accuracy of the measured displacements.
Abstract: Digital Image Correlation (DIC) - also referred to as white light speckle technique - is an optical-numerical full-field measuring technique, which offers the possibility to determine in-plane displacement fields at the surface of objects under any kind of loading. For an optimal use of the method, the object of interest has to be covered with a speckle pattern. The present paper studies the efficiency of a random speckle pattern and its influence on the measured in-plane displacements with respect to the subset size. First a randomly sprayed speckle pattern is photographed three times. Each picture is taken with a different zoom, yielding three speckle patterns, which are different by the size of the speckles. Secondly a number of speckle patterns are generated numerically using a given speckle size and image coverage. Subsequently, each speckle pattern image undergoes a numerically controlled deformation, which is measured with digital image correlation software. Both imposed and measured displacements are compared and it is shown that the size of the speckles combined with the size of the used pixel subset, clearly influences the accuracy of the measured displacements. Furthermore it is shown that it is possible to create an optimal speckle pattern when a given subset size is chosen.
41 citations
TL;DR: The flash x-ray technique allowed examination of the deformation at the layer inside the material during failure, thus giving interesting data about the material flow field around the impactor.
Abstract: A technique to measure two-dimensional deformation fields of a layer inside materials during dynamic events such as impact experiments is presented. Even optically opaque materials like cement can be evaluated when flash x rays are used. Blocks of polyester and cement were prepared with a layer of x-ray-absorbing lead particles. The specimens were then hit by a 9-mm-diameter steel sphere (ball bearing) fired from a 9-mm-bore gas gun at a velocity of 373.5 +/- 3.0 ms(-1). A 30-ns-long x-ray pulse exposed one radiograph before impact; another radiograph was exposed a short time after the impact on the specimen. The two-dimensional displacement field was obtained when the x-ray radiographs were digitized by a conventional flatbed scanner, and a digital speckle photography algorithm was used to calculate the displacements. The flash x-ray technique allowed examination of the deformation at the layer inside the material during failure, thus giving interesting data about the material flow field around the impactor.
41 citations