Information Technology Reference
In-Depth Information
Fig. 5.2 Zero isoclines of
the photosensitive
Belousov-Zhabotinsky
reaction in the dark and
under light irradiation.
v
and
u
—activator and inhibitor
In this case, light emission does not affect the second linear isocline (Fig.
5.2
). As a
result, intersection points of the isoclines shift along the S-shaped curve to the area
of higher concentrations of the activator of the reaction and extremely low concen-
trations of the inhibitor.
Let us consider qualitatively the process of entering information. Suppose that a
black-and-white image is projected on the medium, whose composition corre-
sponds to the vibrational mode. In this case, the spatial regions of the medium
affected by intense radiation are transferred to a state with a high content of the
activator of the reaction. At the same time, spatial areas on which no light is falling
do not change their status. When the exposure of the light emission ends, the
evolution of the input image begins in the media driven by the reactions in the
medium. Those areas of the medium on which no light emission fell immediately
enter the oscillatory process, while illuminated areas will need some time until
chemical reactions transfer them into an oscillatory regime.
Orange-red and blue colors of the reagent correspond to high content of activator
and inhibitor in the medium, respectively. In practice, when monitoring the evolu-
tion of the image, blue light filters are used in order to increase its contrast. As a
result, the registration of the evolution of the image by a black-and-white video
camera makes the regions of the medium with a high content of activator appear
dark and those with a high content of inhibitor appear bright.
Thus, during the evolution of a black-and-white image introduced into an
oscillating medium, bright fragments (which are dark on the input image) appear
on a dark background corresponding to the illuminated fragments (which are bright
on the original input image). In other words, at the initial stage of the evolution, a
negative form of the input picture appears. This process is shown in Fig.
4.10
of the
previous chapter.
