Page 136 - Biomimetics: Technology Imitates Nature

Biomimetics: Technology Imitates Nature

stars quite clearly, because our eyes automatically set themselves accord-
ing to various intensities of light. Muscles around the pupil allow this to
happen. If our surroundings are dark, these muscles expand, the pupil
widens and more light is allowed into the eye. With plenty of light, the
muscles contract, the pupil shrinks and less light is permitted to enter.
That is why we enjoy clear vision both night and day.

A Window on a Colored World
The eye “snaps” both a black-and-white picture and a colored one at
the same time. These two pictures are later combined in the brain, where
they take on a normal appearance, in much the same way as four-color
photography combines black with red, yellow, and blue to produce a re-
alistic full-color image.
The rod cells in the retina perceive objects in black and white, but in
a detailed manner. The cone cells identify the colors. As a result, the sig-
nals received are analyzed, and our brains form a colored image of the
outside world.

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