<title>Adaptive conversion of visual information by noncomputing method</title>

Abstract

A new method of visual information processing is discussed. As a particular example, porous silicon is considered as a material, characterized by progressively decreasing luminescence quantum yield at constant excitation intensity. Discrimination of moving object was shown to be possible when visual information is displayed using a luminescent screen, made ofa such material. 2.INTRODUCTIONThe invention of new materials, as a rule, give rise to numerous applications, while the most of those were not evident on the initial stage of materiaidevelopment . The active research and application studies ofporous silicon were started after pioneeringwork '. This material was considered as possible substitution for gallium arsenide and related materials in optoelectromc devises 2 This supposition was based on high quantum yield of porous silicon photoluminescence ( of about ten percents ) in visible spectral region. The special advantage of this material goes from the fact, that the production of porous silicon elements appear to be compatible with the standard silicon technology .At the same time it was observed, that the luminescence of porous silicon demonstrated specific property, called "luminescence fatigue" -the essential decrease of quantum yield after the beginning of the process of steady excitation. The model was developed for explanation of the phenomenon, assuming the accumulation of non-radiative recombination centers during the sample exposure . It is to note, that <<fatigue>> effect was observed for all types of samples, regardless of initial silicon characteristics as well as of procedures, used to produce porous silicon. Experimental temporal dependence of the porous silicon luminescence intensity under steady state excitation conditions are shown in Fig. 1. 516 SPIE Vol. 3407 . 0277-786X/98/$1O.00 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/20/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx