25.11. Spectral Imaging Becomes More Closer to the Life

Public examination of a doctoral dissertation in the field of Computer Science

Doctoral candidate: Diploma Specialist, M.Sc. Alexey Andriyashin 

Date and venue: 25.11.2011, at 12 noon, Louhela Auditorium in Joensuu Science Park 

Digital imaging rapidly penetrates to different areas of our life. It has become an obvious to use digital photo and video cameras instead of analog and tape based ones. The main reason of that - digital images are protected from external factors (e.g. ageing, corrosion and discoloration). Also, digital technologies enable transferring copies of digital images over long distances in a short time and representing them in different ways (e.g. paper or textile printing, computer or mobile device representation and light projection). 

But, the most common trichromatic color technologies nowadays, such as RGB (Red Green Blue), are affected e.g. by metamerism (the effect of matching of the color of objects with different spectral power distributions) and are device and observer dependent. Therefore the color spectrum for accurate and device independent color representations is needed. Spectral image, also called a multispectral or hyperspectral image, is a digital image where each pixel is a color spectrum. The image captured by spectral camera is more accurate representation of color information than captured by mono or three chromatic cameras. 

The purpose of digital image archives is to store images in an organized order for future use. Alexey Andriyashin from University of Eastern Finland considered three fundamental processes of the spectral image archive, which are also relevant for any digital image archive. The processes of acquisition, compression and retrieval were accurately investigated in his thesis titled “Non-negative bases in spectral image archiving”. The benefits of application of non-negative methods (e.g. Non-negative Matrix Factorization (NMF) and Non-negative Tensor Factorization (NTF)) were proved by series of a scientific experiments. The results of the experiments were published in international conferences where Alexey has been a part to. Modern and convenient methods are introduced, implemented and compared for each component of the archive. The direction for future research in the area of spectral image archiving was proposed. 

The doctoral dissertation of Alexey Andriyashin entitled Non-negative bases in spectral image archiving” will be examined at the Faculty of Science and Forestry.The opponent in the public examination is Professor Karen Egiazarian, Tampere University of Technology and the custos is Professor Markku Hauta-Kasari of the University of Eastern Finland.

Photo available for download at http://www.uef.fi/vaitoskuvat

Contact: Alexey Andriyashin, tel. +358 50 480 1560, alexey.andriyashin@uef.fi

Publishing year: 2011

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