Abstract. The scanning nuclear microprobe analytical facility of the IRMM was used to determine with PIXE major, minor and trace elements in individual giant marine aerosol particles, collected above the North Sea (particle size > 5 #m ~). The instrumentation is briefly described, and the experimental parameters chosen for these analyses are discussed. Elements with atomic numbers Z > 15 could be determined. Detection limits observed under the prevailing experimental conditions reached down to 50 fg in the case of Ti, V or Cr, corresponding to a mass content of 10 #g/g in particles of 15 #m size. Quantitative evaluation of the acquired spectra revealed basically three aerosol types in these samples: sea salt particles, sea salt combined with high contents of S, K and Ca, and particles rich in heavier elements (Ti, Cr, Fe, Ni). The agglomeration of several large particles forming a giant one could be visualised directly through the heterogeneity found in the elemental maps of such a particle.

Multimodal biometrics offer superior matching performance over a single biometric. However real-life applications increasingly deploy biometric matching systems in non-ideal conditions where good image quality cannot be assured. We assess the impact of image quality on multimodal biometric recognition performance. Biometric recognition of face and iris is carried out on images while the image quality is varied. Image quality is controlled synthetically using defocus, motion blur, light intensity, contrast, resolution and color reduction.Results show that the chosen algorithm for iris recognition is highly sensitive to contrast while brightness has less influence. Effect of defocusing and motion blur on the performance is linear. The effect of pixel resolution is log-linear whereas color reduction has more pronounced effect at extreme values only. The face recognition algorithm is robust to the same variations even though the corresponding image quality followed the trends similar to that for the iris images. For face matching, quality was not a predictor of performance.

No abstract

No abstract

No abstract