José Alberto de Oliveira

São Paulo State University, San Paulo, São Paulo, Brazil

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Publications (3)4.19 Total impact

  • Luis Rogerio de Oliveira Hein · José Alberto de Oliveira · Kamila Amato de Campos
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    ABSTRACT: The correlative light-electron fractography technique combines correlative microscopy concepts to the extended depth-from-focus reconstruction method, associating the reliable topographic information of 3-D maps from light microscopy ordered Z-stacks to the finest lateral resolution and large focus depth from scanning electron microscopy. Fatigue striations spacing analysis can be precisely measured, by correcting the mean surface tilting with the knowledge of local elevation data from elevation maps. This new technique aims to improve the accuracy of quantitative fractography in fatigue fracture investigations. Microsc. Res. Tech., 2013. © 2013 Wiley Periodicals, Inc.
    No preview · Article · Sep 2013 · Microscopy Research and Technique
  • Luis Rogerio de Oliveira Hein · José Alberto de Oliveira · Kamila Amato de Campos
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    ABSTRACT: Correlative fractography is a new expression proposed here to describe a new method for the association between scanning electron microscopy (SEM) and light microscopy (LM) for the qualitative and quantitative analysis of fracture surfaces. This article presents a new method involving the fusion of one elevation map obtained by extended depth from focus reconstruction from LM with exactly the same area by SEM and associated techniques, as X-ray mapping. The true topographic information is perfectly associated to local fracture mechanisms with this new technique, presented here as an alternative to stereo-pair reconstruction for the investigation of fractured components. The great advantage of this technique resides in the possibility of combining any imaging methods associated with LM and SEM for the same observed field from fracture surface.
    No preview · Article · Feb 2013 · Microscopy and Microanalysis
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    ABSTRACT: In this work, NIH ImageJ plugins for extended depth-from-focus reconstructions (EDFR) based on spatial domain operations were compared and tested for usage optimization. Also, some preprocessing solutions for light microscopy image stacks were evaluated, suggesting a general routine for the ImageJ user to get reliable elevation maps from grayscale image stacks. Two reflected light microscope image stacks were used to test the EDFR plugins: one bright-field image stack for the fracture of carbon-epoxy composite and its darkfield corresponding stack at same (x,y,z) spatial coordinates. Image quality analysis consisted of the comparison of signal-to-noise ratio and resolution parameters with the consistence of elevation maps, based on roughness and fractal measurements. Darkfield illumination contributed to enhance the homogeneity of images in stack and resulting height maps, reducing the influence of digital image processing choices on the dispersion of topographic measurements. The subtract background filter, as a preprocessing tool, contributed to produce sharper focused images. In general, the increasing of kernel size for EDFR spatial domain-based solutions will produce smooth height maps. Finally, this work has the main objective to establish suitable guidelines to generate elevation maps by light microscopy. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.
    No preview · Article · Jul 2012 · Microscopy Research and Technique

Publication Stats

5 Citations
4.19 Total Impact Points


  • 2013
    • São Paulo State University
      • Faculty of Engineering of Guaratinguetá
      San Paulo, São Paulo, Brazil
  • 2012
    • University of São Paulo
      San Paulo, São Paulo, Brazil