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Electronics greatest technological breakthrough in this modern age is
the digitization of analog signals. Digital information, which is
represented by 1s and 0s, is formed upon successful conversion of
analog information, which is represented by a fluctuating wave. This
conversion of analog to digital has made the world of science and
technology make great advances into the field of computers, Internet,
satellites, and space research.
On the consumer domain, the benefits of this technological breakthrough
can be witnessed in consumer electronic products like TVs, computers,
cameras, camcorders, CDs, DVDs, etc. Digitization gave rise to
microchips, which could be programmed to perform any task. With the
utilization of the microchip, the digital camera was born.
In a digital camera, the lens focuses the image, the shutter allows the
entry of light reflecting from that image into the camera, for a
fraction of a second, and the aperture determines the quantity of light
allowed inside the camera. When the light enters the camera, it does
not fall on a photographic film as it does in a conventional camera,
rather it falls on an image sensor.
The image sensor is an electronic device, a semiconductor, made up of
photosites that measures the light intensity. The photosite can only
measure the intensity of light and cannot recognize any color. To
overcome this, each photosite is covered with a color filter of red, or
a green, or a blue color according to a pattern known as the Bayer
pattern. Since the human eye is twice sensitive to the green color, the
number of photosites having green color is twice the number of
photosites having red or blue color. Millions of photosites are covered
by this Bayer pattern. Each color occupies a single photosite, which is
known as a pixel.
The more the number of pixels, the greater is the amount of detail that
can be captured. The detail of the image is called as resolution, which
is determined by the quality of the lens and the number of pixels in
the image sensor. High-end digital cameras have about 12 million
pixels, whereas professional digital cameras have about 20 million
pixels.
The information of the pixels is recorded as electrical analog signals,
is amplified, and then is fed into a converter, which converts the
amplified analog signals into digital binary numbers, with respect to
the color information of each pixel. These digital binary numbers are
then fed into a computer chip residing inside the camera. The computer
chip analyzes the digital binary numbers that have been made as per the
color of individual pixels. This information is known as RAW data. For
analysis, the computer chip subjects this RAW data using a technique
known as demosaicing.
In this technique (demosaicing), the pixel color is determined as per
the color of the neighboring pixels. For example, if a red color pixel
is surrounded by blue and green pixels, then that red color pixel is
treated as white color, since the color white is a combination of the
colors, red, blue, and green. After demosaicing is complete, the image
is further subjected to the photographer`s settings of the camera, like
adjustments made for brightness, color saturation, contrast, etc.
High-end digital cameras usually do not do anything more to the image
thus produced. However, professional digital cameras have a sharpening
algorithm, which heighten the sharpness and clarity of the demosaiced
and settings adjusted image. Professional digital cameras also have the
option of saving the image in its RAW data before any demosaicing or
adjustments are made by the computer chip. This is to give control to
the professional photographers to make changes to the RAW data as per
their own choices.
The image can be saved in an uncompressed format like TIFF or a
compressed format like JPEG. Uncompressed formats preserve greater
information; thus, the detail of the photograph is much more than a
compressed format, where detail is less, as lesser information is
stored. Hence, compressed formats are also known as lossy formats,
since details are lost. An uncompressed format increases the file size,
whereas a compressed format reduces the file size. Depending upon the
need, the image can be saved either in an uncompressed or a compressed
image format, as bits and bytes in a memory card. The stored image can
be viewed on the digital camera`s display screen as a digital photo.
This digital photo can then be transferred from the digital camera to
the computer`s hard disk via the serial port or USB port or FireWire
port or Bluetooth wireless using Wi-Fi connectivity. RAW data and
uncompressed data like TIFF take a longer time to transfer than
compressed data like JPEG or GIF.
Once the data has been transferred to the computer`s hard disk, any
photo editing software can manipulate and adjust it, as per the
individual tastes and requirements of the photographer. The digital
photo can then be printed on photographic paper, specially coated
paper, or any other paper via a color inkjet or laser printer.
Utilizing a plotter, it can be printed in larger sizes, in any other
medium like canvas, acrylic, vinyl, etc. The digital photo can be saved
on a hard disk, pen drive or a CD, for archival purposes.
With passing time, more and more features are being introduced in a
digital camera. Nowadays, audio-video recording is also fused with the
still image capturing capability of the digital camera, making them
small camcorders (camera + recorders).
About the Author
This article can be accessed in portuguese from News Article section of page www.polomercantil.com.br/camera-digital.php
Roberto Sedycias works for www.PoloMercantil.com.br
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