Main directions of research of LOEP

1. Studies of the properties of ferroelectric liquid crystals (FLC) and development of light modulators and liquid-crystal displays on their basis

Studies of the physical properties of FLC. FLC have a high sensitivity and fast response to the action of an electric field and exhibit a variety of interesting electrooptical effects. Knowledge of the physical properties of FLC depending on electric-field parameters, boundary conditions and composition of FLC makes it possible to create liquid-crystalline light-modulating cells with required optical and dynamic parameters. This is the basis for developing fast light modulators and liquid-crystal displays, including three-dimensional displays, with optical response on/off time in the submillimeter range.
Development of methods and devices of electrically controlled light modulation based on multilayer thin-film structures using electrooptical effects in FLC.  These structures make it possible to develop low-voltage and, at the same time, fast-response optical gates, light intensity and polarization switches for light beam- and information imaging-control devices and systems, optoelectronic data processing, telecommunications, adjustable optics, etc.

• For instance, the discovery of bistable- and multistable-type optical memory in the FLC structure opened a possibility of developing passively addressed displays with the two-colour or multi-colour scale, which preserve an image after the electric field is switched off.
  
• Electric field-controlled light scattering in FLC is used for visualization of a voluminous object (scene) in a new type of 3D display (of the type of an aquarium). The way an observer, due to visual inertia, can see the entire picture (but not the lines that form it) on a usual two-dimensional display, the same way in a voluminous 3D display different observers can simultaneously see the complete light model of an object (even from different distances and different sides) instead of its cross sections formed in turns. This opens up the possibilities for efficient uses of an "voluminous" display in science and technology for visualization of 3D data and modelling objects and processes.

2. Methods of parallel information processing based on fuzzy and multivalued logics and development of optoelectronic intellectual systems on their basis

Studies of methods of multivalued and fuzzy logics and their potential for data processing. The mathematical basis of the methods is fuzzy logic and Allen-Givone algebra. The methods are used for parallel processing of data arrays characterized by a large number of variables and/or ill-defined functional dependences and, because of this, poorly yielding to formal description. This situation takes place in optoelectronic information systems of complex architecture, with a large number of sensors and actuators. In this case the methods can be used to describe and store informative characters and to increase the density of processed and stored information. They are convenient for describing the characteristics of optical radiations and images and are efficient in constructing models and algorithms of intellectual actions of man and groups of people. All this makes possible the development of distributed architectures of processing, as well as the construction of fuzzy-logic models of complex processes, which require coordinated action of sensors and actuators.

Development of optoelectronic nodes and systems with intellectual functions. Based on the methods of multivalued and fuzzy logic, multisensor circuits, optical fibres and laser diode arrays, we develop multi-input logic valves for operation with discrete and continuous truth values, nodes of establishing cause-and-effect relations, hierarchy charts for accumulation of fuzzy models of observed objects. The results of these works are the basis for constructing hardware-distributed systems of data and knowledge collection and processing, for creating automated image-recognition systems, as well as robotized optoelectronic multi-agent systems with intellectual functions.

3. Image analysis and invariant recognition and optical qualimetry of materials and products based on these methods

Image analysis and invariant recognition. In distinction from Fourier-matched filtering, which provides for invariance only to image motion, we investigate and evaluate in applications the phase portrait method, which is based on Fresnel transformation and provides for (complete) invariance to rotation and change of scale of images. The method gives a significant gain in the signal-to-noise ratio in the recognition of images under interference conditions and has a greater accuracy of determining their coordinates as compared with the known correlation methods.

The correlation statistical two-step method of image analysis is being developed, when first, accurate to unknown linear / nonlinear transformations of filtration, by assessment by the plausible maximum of unknown interference power, we synthesize non-linear correlation silimarity measures of filtered nonstationary signals; then, based on the  maximization of the new selectivity criterion (discriminating / resolving ability), filtration transformations themselves are found. When using additional nonlinear filtration of signals with the base of T counts, when we pass from signals themselves to connectivity matrices of their components in T(T-1)/2 counts, the volume of calculations increases but the gain in respect with the signal-to-noise ratio by power reaches [(T-1)/2]1/2 times as compared with linear filtration.

Experimental elaboration of the developed methods of object / signal / image analysis and recognition is being carried out.