Real-Time Opitical Spatial Filtering Using Anisotropic Properties of Bacteriorhodopsin Photocycle Intermediates

Elena Korchemskaya and Dmitrij Stepanchikov

Institute of Physics, National Academy of Sciences, Prospect Nauki 46, Kiev-39, 03039 Ukraine

e-mail: elkorch@iop.kiev.ua
 

In recent years photoinduced anisotropic properties of bacteriorhodosin (bR), a biological photoreceptor and transmembrane photosensitive protein of the halophilic microorganism Halobacterium salinarum have attracted a lot of attention for achieving a self-adaptive spatial filtering in the bR films [1-5]. The bR molecules both in the initial form bR570 and longest-lived intermediate M412 possess anisotropic absorption [6]. By analogy with hologram types [7], we designate the method of photoinduced anisotropy based only on anisotropic properties of bR570 as "B-type anisotropy", the method based only on anisotropic properties of M412 as "M-type anisotropy", and the method based on anisotropic properties of both bR570 and M412 as "B-M-type anisotropy". We have shown that mixed B-M-type anisotropy produces the highest photoanisotropic response: it is nearly three times greater than that for the M-type and twice as large as that for the B-type [8].

In this work, we propose the techniques of the spatial-intensity filtration, edge enhancement, contrast reversal and image logic processing using B-M-type anisotropy in bR-films. The He-Ne laser, l=633nm and He-Cd laser, l=442 nm are concurrently employed for these real-time image processing techniques. It is possible to achieve both the suppression and selection of image features, having a particular intensity. Even the suppression of a background with greater intensity than the usable signal intensity can be performed. These methods are adopted for Fourier filtering.

We assume that the B-M-type of photoinduced anisotropy is quite promising specifically for high-speed optical image processing. However the study of anisotropic properties of other bR photocycle intermediates significantly extends the capabilities of these applications.

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