The term pixel has been coined
for a few decades, precisely since the digital image originated since it arises
from the acronym of the concept in English "Picture Element," which
in Spanish means image element.
Basically, we could say that the
pixel is the smallest homogeneous unit in a color that makes up the digital
image. Hence, when we observe and talk about a digital
photograph, a video, or others, we refer to its pixels.
Therefore, the
concept of pixel refers to the points that are used within a set to be able to
display an image within a screen or a printed image, and
that is why the term can be used to refer to the smallest unit of an image.
Anyway, at this point, it is
important to clarify that the pixel is not a measure of size, so
when the term is used in that way, we are actually making a misconception.
This confusion that is generated
in most users is usually given by information about digital cameras
since manufacturers generally offer the buyer camera data related to a
measurement of pixels per inch, known as PPI.
When the user reads
this information, he thinks that it refers to a certain size of the
image, but the truth is that it means the number of pixels embedded in
the image that we will create with the camera. Of course, the fact
that the number of pixels can determine the quality that the captured image
will have on display is correct.
In addition to
referring to the points that make up a digital image, pixels are also
related to screens since they are made up of several million pixels,
which are arranged in a grid.
In this sense, we
can observe that the resolution of a screen is usually given in terms of the number
of image elements available in each direction of the screen, so a screen that
indicates that it has a resolution of 1024 x 768, which he is referring
to is that it is 1,024 pixels wide and 768 pixels high.
On the other hand,
it is important to mention that for the visualization of what we see on a
computer or telephone screen to have the appropriate characteristics, the
pixels are made up of other smaller elements, since each pixel
includes three points inside, one red, one blue, and one green, which we call
the RGB standard.
These three points
that are part of a pixel converge at the same point, giving rise to the
possibility of completing the color and shape assigned to each pixel within an
image.
At this point, we
must talk about the so-called pixel density, a concept that
refers to the number of pixels that a certain space of a digital image has, so
ultimately, the information about pixel density will indicate the number
of elements that make up an image.
For this reason,
and as we mentioned earlier, the higher the pixel density, the higher the image
quality. This is fundamentally due to the fact that the greater
the number of pixels in a given space, it is possible to achieve a higher
resolution of the image, which results in being able to achieve
greater detail.
That is why ultimately, the image
quality will depend on the number of pixels that a digital camera can capture,
that is, the resolution that it will produce when generating the photograph,
which, as we saw, is
generally measured in PPI (pixels per inch).
As an example of this, we could
point out that a standard photo of those used in the field of commercial
photography, having a size of around 20 x 25 centimeters, with a
resolution of 300 PPI, would be made up of 7.2 million pixels.
But also, we must bear in mind
that when we talk about digital cameras, we will see that, in general, most
manufacturers have replaced the term pixels with megapixels, which
use it to describe the resolution that a camera has to capture photographs.
In this context,
the resolution that a camera can provide in its photos is usually given in
terms of two dimensions, for example, 1600 x 1200, indicating a width and a
height for the image, which results from the total sum of pixels
generated by multiplying the two dimensions.
The calculation in
the case that a digital camera allows to capture photographs in a resolution of
1600 x 1200, then refers to the fact that the equipment is capable of
generating images that would include 1,920,000 pixels, that is, 1.9 megapixels.
As web cam advanced concurrently with show technologies, USB interface speeds and
broadband net speeds, the decision went up from regularly from 320×240, to
640×480, and a few now even provide 1280×720 (aka 720p) or 1920×1080 (aka
1080p) decision.
