#### Filter Results:

- Full text PDF available (4)

#### Publication Year

2002

2012

- This year (0)
- Last 5 years (0)
- Last 10 years (5)

#### Publication Type

#### Co-author

#### Journals and Conferences

Learn More

- Ramkumar Narayanswamy, Gregory E. Johnson, Paulo E. X. Silveira, Hans B. Wach
- Applied optics
- 2005

The use of the human iris as a biometric has recently attracted significant interest in the area of security applications. The need to capture an iris without active user cooperation places demandsâ€¦ (More)

- Robert J. Plemmons, Michael Horvath, +9 authors Paulo E. X. Silveira
- 2004

Computational imaging systems are modern systems that consist of generalized aspheric optics and image processing capability. These systems can be optimized to greatly increase the performance aboveâ€¦ (More)

- Paulo E. X. Silveira, Ramkumar Narayanswamy
- Applied optics
- 2006

We analyze the signal-to-noise ratio (SNR) of arbitrary imaging systems in the presence of defocus. The modulation transfer function (MTF) and the mean SNR are combined to calculate theâ€¦ (More)

- Saeed Bagheri, Paulo E. X. Silveira, George Barbastathis
- Journal of the Optical Society of America. Aâ€¦
- 2009

We discuss the limit of the depth-of-field (DOF) extension for an imaging system using aspheric surfaces. In particular we consider an imaging system with an arbitrary pupil function and present theâ€¦ (More)

- Ramkumar Narayanswamy, Paulo E. X. Silveira, Harsha Setty, V. PaÃºl Pauca, Joe van der Gracht
- 2007

Iris recognition imaging is attracting considerable interest as a viable alternative for personal identification and verification in many defense and security applications. However current irisâ€¦ (More)

- Saeed Bagheri, Paulo E. X. Silveira, Ramkumar Narayanswamy, Daniela Pucci de Farias
- Journal of the Optical Society of America. Aâ€¦
- 2008

In this paper we use our derived approximate representation of the modulation transfer function to analytically solve the problem of the extension of the depth of field for two cases of interest:â€¦ (More)

- Andrew Kiruluta, Gour S Pati, Gregory Kriehn, Paulo E. X. Silveira, Anthony W Sarto, Kelvin H. Wagner
- Applied optics
- 2003

We present a spatio-temporal operator formalism and beam propagation simulations that describe the broadband efficient adaptive method for a true-time-delay array processing (BEAMTAP) algorithm forâ€¦ (More)

- Saeed Bagheri, Paulo E. X. Silveira, Daniela Pucci de Farias
- Journal of the Optical Society of America. Aâ€¦
- 2008

In this paper we derive an approximate analytical representation for the modulation transfer function (MTF) of an imaging system possessing a defocused cubic-phase pupil function. This expression isâ€¦ (More)

- N. D. Kapale, R. N. Kankarale, +17 authors Paulo E. X. Silveira
- 2012

Biometric user authentication techniques have evoked an enormous interest by science, industry and society in the recent past. Scientists and developers have constantly pursued the technology forâ€¦ (More)

- Eric J. Tremblay, Joel Rutkowski, +6 authors Joseph E. Ford
- Applied optics
- 2007

Annular folded imagers can be up to 10x thinner than corresponding full-aperture imagers, but have tight fabrication tolerances and relatively shallow depth of focus. Wavefront coding, the use ofâ€¦ (More)