Proceedings XIV Brazilian Symposium on Computer Graphics and Image Processing, 2001
Using digital image processing and pattern recognition techniques, a supervised classification pr... more Using digital image processing and pattern recognition techniques, a supervised classification procedure of bamboo vascular bundles was developed and tested on polished cross sections of bamboo culms from four different species. Results obtained for same species samples were similar and were consistent with visual observations
A pattern recognition technique for the detection of structural units in high resolution images o... more A pattern recognition technique for the detection of structural units in high resolution images of interfaces is described. The technique uses cross-correlation functions as a means of locating atomic patterns characteristic for an interface and as a measure of similarity between related units. Application is not limited to periodic, or even to planar interfaces. Characteristic structural units can be extracted from an experimental image and some important parameters such as mirror or mirror glide symmetry, and rigid body displacements can be determined without knowledge of the imaging parameters. The technique allows an image of a structural unit with reduced specimen noise to be obtained by averaging over several similar units, even if a boundary is not periodic and not planar.
In this study, a comparative topography analysis of titanium (Ti) surfaces was performed using tw... more In this study, a comparative topography analysis of titanium (Ti) surfaces was performed using two- (2D) and three-dimensional (3D) profilometers. Ti samples were either only sandblasted (SB) using Al(2)O(3) particles or were SB and received an additional chemical treatment using a solution of 4% HF (SLA). Samples with no treatment were used as a control group (C). Therefore, three different surfaces were evaluated: SB, SLA and C. The Ti surface topographies were evaluated by scanning electron microscopy. An Ra roughness measurement was performed on each Ti sample by 2D and 3D profilometers. Surface roughness was also characterized using amplitude, spatial and hybrid 3D parameters. 2D and 3D profilometer analyses produced very close results. Mean Ra values range from 0.19 to 0.25 (C, p<0.05), 0.84 to 0.99 (SLA, p<0.05) and 0.98 to 1 microm (SB, p>0.05). The statistically different Ra values depending on the surface studied may be explained by methodological and technical differences. Also, 3D profilometer seems to be the more appropriate analytical method for measuring the roughness of Ti surfaces because it also describes surface organization.
We show that the equilibrium shapes of small solid Pb inclusions embedded in an Al matrix are siz... more We show that the equilibrium shapes of small solid Pb inclusions embedded in an Al matrix are size dependent. Using high resolution electron microscopy we have observed that small inclusions a few nanometers in size adopt equilibrium shapes with smooth {111} facets. Inclusion ...
The absorption, emission and excitation optical spectra of F2 and F+3 color centers generated in ... more The absorption, emission and excitation optical spectra of F2 and F+3 color centers generated in LiF through low energy (30 keV) electron beam irradiation were measured at room temperature by pumping with an Ar+ laser the resulting thin colored layer. A quenching of the emission intensity of the F+3 centers versus the pump power was observed, with characteristics similar to
Proceedings XIV Brazilian Symposium on Computer Graphics and Image Processing, 2001
Using digital image processing and pattern recognition techniques, a supervised classification pr... more Using digital image processing and pattern recognition techniques, a supervised classification procedure of bamboo vascular bundles was developed and tested on polished cross sections of bamboo culms from four different species. Results obtained for same species samples were similar and were consistent with visual observations
A pattern recognition technique for the detection of structural units in high resolution images o... more A pattern recognition technique for the detection of structural units in high resolution images of interfaces is described. The technique uses cross-correlation functions as a means of locating atomic patterns characteristic for an interface and as a measure of similarity between related units. Application is not limited to periodic, or even to planar interfaces. Characteristic structural units can be extracted from an experimental image and some important parameters such as mirror or mirror glide symmetry, and rigid body displacements can be determined without knowledge of the imaging parameters. The technique allows an image of a structural unit with reduced specimen noise to be obtained by averaging over several similar units, even if a boundary is not periodic and not planar.
In this study, a comparative topography analysis of titanium (Ti) surfaces was performed using tw... more In this study, a comparative topography analysis of titanium (Ti) surfaces was performed using two- (2D) and three-dimensional (3D) profilometers. Ti samples were either only sandblasted (SB) using Al(2)O(3) particles or were SB and received an additional chemical treatment using a solution of 4% HF (SLA). Samples with no treatment were used as a control group (C). Therefore, three different surfaces were evaluated: SB, SLA and C. The Ti surface topographies were evaluated by scanning electron microscopy. An Ra roughness measurement was performed on each Ti sample by 2D and 3D profilometers. Surface roughness was also characterized using amplitude, spatial and hybrid 3D parameters. 2D and 3D profilometer analyses produced very close results. Mean Ra values range from 0.19 to 0.25 (C, p<0.05), 0.84 to 0.99 (SLA, p<0.05) and 0.98 to 1 microm (SB, p>0.05). The statistically different Ra values depending on the surface studied may be explained by methodological and technical differences. Also, 3D profilometer seems to be the more appropriate analytical method for measuring the roughness of Ti surfaces because it also describes surface organization.
We show that the equilibrium shapes of small solid Pb inclusions embedded in an Al matrix are siz... more We show that the equilibrium shapes of small solid Pb inclusions embedded in an Al matrix are size dependent. Using high resolution electron microscopy we have observed that small inclusions a few nanometers in size adopt equilibrium shapes with smooth {111} facets. Inclusion ...
The absorption, emission and excitation optical spectra of F2 and F+3 color centers generated in ... more The absorption, emission and excitation optical spectra of F2 and F+3 color centers generated in LiF through low energy (30 keV) electron beam irradiation were measured at room temperature by pumping with an Ar+ laser the resulting thin colored layer. A quenching of the emission intensity of the F+3 centers versus the pump power was observed, with characteristics similar to
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