|  That new digital
camera, 10 million pixels. That new LCD, 2 million pixels. So
what’s a pixel? Well first a pixel is short for picture
element (pix----element----pixel). But a pixel isn’t really
anything. It is not like an inch or a gram or any real way of
measuring something. It is just a way of breaking down a picture
into the smallest piece. On an average computer screen there might
be 500,000 or more pixels. The bigger the screen usually the more
pixels. More pixels mean better resolution, things look sharper.
The images and the colors that you see on a TV or computer screen
depend upon how the screen works. But in general they take digital
information, and then send little electrical signals to the screen
where the electrical signal is changed into a color. There are
different ways to do that, some involve crystals that change their
ability to let light pass while others involve chemicals that
give off light when they are excited by the electrical signals.
 Digital
camera can take pictures with over 10,000,000 pixels. Cameras
with more and more resolution are a result of improvements in
nanotechnology the same technology that is used to make computer
chips. They work kind of opposite to the way a computer screen
works. Inside of the camera is something called a charged coupled
device (CCD). A CCD is a gizmo that takes light and converts it
into a digital piece of information which can be stored. The CCD
has a million or more of these sensors each of which records a
portion of the light from an image. The picture on the right shows
a CCD chip magnified 7000 times. So the more sensors, the more
pixels, the better the resolution.
So what is the resolution of the human eye? Well it depends
upon a lot of things including how good your eyes are. But the
estimates are around 300 to 500 million pixels. That means that
if you look at something you can break it down into 300-500 million
different pieces. Pieces that you brain puts together into one
big picture. That is a lot better than the most of the digital
cameras or computer screens around.
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