Bio-medical Ontologies Maintenance and Change Management

90 L. Stanescu, D. Dan Burdescu, and M. Brezovan
The color represents more than a property of an object, but that is in
contradiction with the sense of the word we use in daily language. The association
in our language between a color and an object (for example: this object is red) is
wrong, because, with no doubt, the color exists only in our mind.
The color is the result of three factors: the nature of the physical world,
physiological answer to light of the eye’s retina and the neural processing of the
retina’s answer from the brain. As we can see, the number three has an almost
magical association with the notion of color.
3.3 Color Perception
We use the eyes to receive most of the information from the outside world. Using
the results provided by a researcher, 80% of our memories are obtained visually.
The eye has the role to provide information – as color images – about depth,
distance, and movement of the objects. Moving the eye up, down and sideways
most of the nearby environment is seen.
Analyzing a photo camera we can understand better how the eye works. The
portion in front of the eye works as an optical lens, similar with the glass lens of
the camera. The optical lens is an object with one or two curbed faces, made from
a transparent material. The light that enters in this object is refracted [96].
The dark side in the center of the eye, the eye pupil, regulates the quantity of
the received light. When the light is week, the dimension of the pupil is increased.
When the light is bright, the dimension is reduced, allowing entering a small
quantity of light. The same thing happens with the camera shutter behind the lens.
The layer inside the eye corresponds to the camera film [96].
The eye is much more complex than the photo camera. Using the camera we
can only put the images from outside world to a film. Instead, humans and animals
can interpret the information received on the retina and act according with the
received information. This is possible because the eye is connected with the brain
using optical nerve. The optical nerve is connected to the posterior side of the eye,
using a small pedicel [96].
The optical information intercepted by the retina is send to the brain using the
optical nerve. The information is sent to the brain as electrical impulses. The brain
receives the impulses and decodes them [96].
The human’s two eyes see the objects from different angles that make the
information sent to the brain to be slightly different. Our brain “learns” how to
ensemble these two images, so we don’t see double images. Combining the two
images, the brain understands the spatial positioning and the distance of objects –
that makes possible three-dimensional seeing.
The brain transforms the image from the upside down position, to normal
position. The light is refracted in the crystalline and projected to the retina as an
upside down image. The brain “reads” the image and rotates it in the normal
position.
The retina is composed by approximately 130 million photo sensible cells –
retinal cons and rods [96]. The rods are very sensible to light but they cannot