Prof. Dimitris Maroulis Profile

Prof. Dimitris Maroulis

at National and Kapodistrian Univ of Athens

SPIE Involvement:

Author

Publications (5)

Proceedings Article | 2 May 2012 Paper

A contourlet transform based algorithm for real-time video encoding

Stamos Katsigiannis, Georgios Papaioannou, Dimitris Maroulis

Proceedings Volume 8437, 843704 (2012) https://doi.org/10.1117/12.924327

KEYWORDS: Video, Video surveillance, Video compression, Computer programming, Video acceleration, Video coding, Visualization, Surveillance, Image filtering, Image compression

Read Abstract +

In recent years, real-time video communication over the internet has been widely utilized for applications like video conferencing. Streaming live video over heterogeneous IP networks, including wireless networks, requires video coding algorithms that can support various levels of quality in order to adapt to the network end-to-end bandwidth and transmitter/receiver resources. In this work, a scalable video coding and compression algorithm based on the Contourlet Transform is proposed. The algorithm allows for multiple levels of detail, without re-encoding the video frames, by just dropping the encoded information referring to higher resolution than needed. Compression is achieved by means of lossy and lossless methods, as well as variable bit rate encoding schemes. Furthermore, due to the transformation utilized, it does not suffer from blocking artifacts that occur with many widely adopted compression algorithms. Another highly advantageous characteristic of the algorithm is the suppression of noise induced by low-quality sensors usually encountered in web-cameras, due to the manipulation of the transform coefficients at the compression stage. The proposed algorithm is designed to introduce minimal coding delay, thus achieving real-time performance. Performance is enhanced by utilizing the vast computational capabilities of modern GPUs, providing satisfactory encoding and decoding times at relatively low cost. These characteristics make this method suitable for applications like video-conferencing that demand real-time performance, along with the highest visual quality possible for each user. Through the presented performance and quality evaluation of the algorithm, experimental results show that the proposed algorithm achieves better or comparable visual quality relative to other compression and encoding methods tested, while maintaining a satisfactory compression ratio. Especially at low bitrates, it provides more human-eye friendly images compared to algorithms utilizing block-based coding, like the MPEG family, as it introduces fuzziness and blurring instead of artificial block artifacts.

SPIE Journal Paper | 1 April 2006

Structure and characterization of an enhanced laser-scanning endoscope based on microelectromechanical mirrors

Hansjörg Albrecht, Panagiotis Papageorgas, Dimitrios Maroulis, Nikiforos Theofanous, Stavros Karkanis, Bernd Wagner, Marc Schurr, Christian Depeursinge, Arianna Menciassi

JEI, Vol. 15, Issue 02, 023003, (April 2006) https://doi.org/10.1117/12.10.1117/1.2194890

KEYWORDS: Endoscopes, Mirrors, Head, Signal detection, Micromirrors, Imaging systems, Tissue optics, Image resolution, Microelectromechanical systems, Laser tissue interaction

Read Abstract +

Proceedings Article | 22 March 2005 Paper

Physical modeling of a microlens array setup for use in computer generated IP

Spyros Athineos, Nicholas Sgouros, Panagiotis Papageorgas, Dimitris Maroulis, Manolis Sangriotis, Nikiforos Theofanous

Proceedings Volume 5664, (2005) https://doi.org/10.1117/12.585842

KEYWORDS: 3D image processing, Microlens, Microlens array, 3D modeling, 3D displays, Photography, Computer simulations, Cameras, Algorithm development, LCDs

Read Abstract +

Proceedings Article | 14 October 2003 Paper

A laser-scanning endoscope based on polysilicon micromachined mirrors with enhanced attributes

Markus George, Hansjoerg Albrecht, Marc Schurr, Panagiotis Papageorgas, Ulrich Hofmann, Dimitris Maroulis, Christian Depeursinge, Dimitris Iakkovidis, Nikiforos Theofanous, Arianna Menciassi

Proceedings Volume 5143, (2003) https://doi.org/10.1117/12.500541

KEYWORDS: Endoscopes, Mirrors, Endoscopy, Head, Laser scanners, Scanners, Neural networks, Video, Tissues, Beam splitters

Read Abstract +

Proceedings Article | 9 April 2003 Paper

Laser-scanning endoscope with enhanced attributes

Nikiforos Theofanous, G. Markus, Christian Depeursinge, D. Maroulis, Panagiotis Papageorgas, Hansjoerg Albrecht, Ulrich Hofmann, Arianna Menciassi

Proceedings Volume 5131, (2003) https://doi.org/10.1117/12.513682

KEYWORDS: Endoscopes, Modulation transfer functions, Mirrors, Signal detection, Laser scanners, Beam splitters, Spatial frequencies, Laser tissue interaction, Optical fibers, Image quality

Read Abstract +

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years