Michael Frydrych

Color sensitive retina based on bacteriorhodopsin.

Bacteriorhodopsin (BR), a membrane protein of a microorganism Halobacterium salinarium has been studied since the 80s as a potential material for information technology. The information processing applications of BR employ either photochromic or photoelectric properties of the protein. In this study we discuss about design principles and describe our study of the use of bacteriorhodopsin as a sensor material for a color sensitive artificial retina. This retina includes low-level processing of input information. The design of a color sensitive matrix element, the self-organizing color adaptation algorithm and a system model for the retina are presented.

Photoelectrical properties of protein-based optoelectronic sensor

Bacteriorhodopsin (BR) has been studied as a biomaterial for molecular computing applications. Thin film elements based on BR in polyvinylalcohol were prepared to determine the photoelectrical properties of the material for the development of an optoelectronic sensor. The properties were studied by registering the photovoltage in time, measuring the intensity, area and wavelength dependence of the photoelectric response, and evaluating the element quality. The thin film elements produce a stable photovoltage, the intensity and area dependencies are close to linear, and the wavelength dependence is closely related to the absorption spectrum of BR. The homogeneity of the element thin films is good based on the relatively small variance of the photoelectric response, thus it is feasible to continue the development of an artificial retina based on BR.

BIOMECHANICALLY BASED MUSCLE MODEL FOR DYNAMIC COMPUTER ANIMATION

Simulation of dynamic motion of soft tissues is one of the most important topic in nowadays computer animation of human body. So far various elastically de- formable models were used for this purpose. We present the extension of model proposed in 15 with volume preserving constraint. We provide also evaluation of the constraint accuracy on two simulation experiments. Furthermore we add model of active and passive force generated by musculo-tendon unit using Za- jacs bio-mechanical model. We use Finite Difference Method for resolution of continuous partial differential equations of internal elastic forces of the model in space. We integrate resulting ordinary differential equations of motion using various explicit and implicit methods.

Joint modeling of facial expression and shape from video

In this paper, we present a novel model for representing facial feature point tracks during an facial expression. The model is composed of a static shape part and a time-dependent expression part. We learn the model by tracking the points of interest in video recordings of trained actors making different facial expressions. Our results indicate that the proposed sum of two linear models – a person-dependent shape model and a person-independent expression model – approximates the true feature point motion well.

Photoelectric response of bacteriorhodopsin in thin PVA films and its model

Bacteriorhodopsin is a protein in the purple membrane of the archaean Halobacterium salinarum. Its natural function is to act as a light-driven proton pump contributing to the energy balancing mechanism in the archaean. Bacteriorhodopsin retains its proton pumping property even when isolated from the purple membrane and incorporated into an artificial membrane or polymeric film. Such bacteriorhodopsin films have been studied as a potential material for information technology. We built optical elements based on bacteriorhodopsin and measured their spectral properties. Here we describe a model of photoelectric response of the elements and compare it to the experimentally measured values.

Model for a color perception system with learning capabilities

We present a model for color vision system with learning capabilities. The system adapts to statistical properties of its input. The adaptation is done by utilizing unsupervised learning techniques, as self-organizing feature maps and vectorial boundary adaptation maps. A color difference reflecting statistical properties of input to the system is defined. The model was tested by using color data with different statistics and two different sets of rhodopsin- based color sensors.