A webcam is a hardware camera and input device that
connects to a computer and the Internet and captures either still pictures or
motion video of a user or other object. Most webcams are either embedded into
the display with laptop computers or connected to the USB or FireWire port on
the computer. Webcams come with software that needs to be installed on the
computer to help users record video on or stream it from the Web.
Technology Behind webcams:
work in broadly the same way, they use an image sensor chip to catch moving
images and convert them into streams of digits that are uploaded over the
Internet. It captures light through a small lens at the front using a tiny grid
of microscopic light-detectors built into an image-sensing microchip either a
charge coupled device (CCD) or a CMOS image sensor. The image sensor and its
circuitry then convert the picture in front of the camera into digital format
which is a string of zeros and ones that a computer can understand and knows
how to handle. Unlike a digital camera, a webcam has no built-in memory chip or
flash memory card because it doesn’t need to remember pictures. It’s designed
to capture pictures and transmit them immediately to a computer. That’s why
webcams have USB cables coming out of the back. The USB cable supplies power to
the webcam from the computer and takes the digital information captured by the
webcam’s image sensor back to the computer, from where it travels on to the Internet.
Image sensor is the heart of webcam or digital camera
and that is the main basis of difference between webcam and a Digital camera.
So the image sensor also called the “electronic eye” of a webcam or a
digital camera. It’s a semiconductor chip made of millions of
tiny, light-sensitive squares arranged in a grid pattern. These squares are
called pixels. Basic webcams use relatively small sensors with just a few
hundred thousand pixels (typically a grid of 640 × 480) whereas good digital cameras use sensors with many
more pixels and that is the reason why cameras are compared by how
many megapixels or millions of pixels they have. A basic webcam has
about 0.3 megapixels that is equal to 300,000 in other words while a digital
camera with 6 megapixels has over 20 times more probably arranged in a
rectangle with three thousand across and two thousand down (3000 x 2000 = 6
million). A better camera rated at 12 megapixels would have a 4000 x 3000pixel
sensor. Take a photo the same size with those two cameras and the 12 megapixel
one is going to give us 1000 more dots horizontally and 1000 more vertically,
these are the smaller dots giving more detail and higher resolution.
How Does Image Sensor WorK:
When we take a digital photo or stare into your
webcam, light zooms into the lens. This incoming picture hits the image sensor,
which breaks it up into individual pixels that are converted into numeric form.
CCDs and CMOS chips, the two kinds of image sensor, do this job in slightly
different ways. Both initially convert incoming light rays into electricity,
much like photoelectric cells. This information is then turned into a number
that can be stored on a memory chip inside the camera, which is different in
CCD and CMOS .CCD is essentially an analog optical chip that converts light
into varying electrical signals, which are then passed on to one or more other
chips where they’re digitized or turned into numbers. But on the other side
CMOS chip does everything in one place, it captures light rays and turns them
into digital signals all on the one chip. CMOS chips work faster and are
cheaper to make in high volume than CCDs, so they’re now used in most low-cost
cellphone cameras and webcams. But CCDs are still widely used in some
applications, such as low-light astronomy. Whether images are being generated by a CMOS
sensor or a CCD and other circuitry, basic process is same. The image sensors
converts the picture we see, while taking a digital photograph, into a very
long string of numbers. Each number describes one pixel in the image, how
bright or dark and what color it is.
How webcam was invented
The idea for the webcam dates back to 1991, when
Cambridge University researchers began looking for a way to remotely monitor
the coffee pot in the Trojan Room of the Computer Science Department. The first strategy the
researchers used in 1991 was to train a digital camera on the coffee pot and
wire it to their computers. A specialized software allowed the researchers to
view the camera’s images.
In 1993, the Cambridge University researchers in the
Computer Science Department took their remote coffee pot-viewing experiment a
step further by updating the images of the digital camera in the Trojan Room to
the Internet. In the process, the researchers created the world’s first webcam.
accomplished this feat by developing a remote procedure call mechanism known as
mechanism operated over the multi-service network layer protocol, which was a
network protocol that researchers had designed for use with ATM machines. Using
the MSRPC2 mechanism in conjunction with a computer’s video capture board
allowed the Cambridge University researchers to upload one frame per second
from their coffee pot camera on to the web.
In 1994, Connectix released the very first commercial
webcam, the QuickCam, which sold for $99. The QuickCam had a maximum recording
resolution of 320 horizontal lines of pixels by 240 vertical lines of pixels;
it could display 16 shades of gray.
The webcam did not come into widespread use until the
2000s. As “PC World” points out, by 2003, Apple, Microsoft and
Logitech were designing and selling webcams. The demand for the webcams rose
rapidly due to the development of video calling, which all of the major
instant-messaging service providers began offering in 2003. As of 2011, people
commonly use webcams for real-time, face-to-face communication. One of the most
recent webcam innovations has been the incorporation of webcams into mobile
devices, such as smart phones.
Uses of Webcam
Webcams typically come with software that allows the
user to record video or stream the video on the Web. If the user has a website
that supports streaming video, other users can watch the video stream from
their Web browsers. Webcams can also be used for video chat sessions with other
people. Instead of broadcasting the video on the Web, users can set up a video
chat session with one or more friends and have a conversation with live audio
and video. Since streaming video over the Internet requires a lot of bandwidth,
the video stream is typically compressed to reduce the “choppiness”
of the video. The maximum resolution of a webcam is also lower than most
handheld video cameras, since higher resolutions would be reduced anyway. For
this reason, webcams are relatively inexpensive compared to most video cameras.
also be used as security cameras, using Yawcam software one can take pictures
at regular intervals and can store them offsite or record activity when motion
Most present day webcams are fit for catching blood
vessel beat rate by the utilization of a straightforward algorithmic trap.
Specialists guarantee that this strategy is precise to ±5 bpm.
A webcam’s CCD response is linear proportional to the
incoming light. Therefore, webcams are suitable to record laser beam profiles,
after the lens is removed. The resolution of a laser beam profiler depends on the
pixel size. Commercial webcams are usually designed to record color images. The
size of a webcam’s color pixel depends on the model and may lie in the range of
5 to 10µm. However, a color pixel consists of four black and white pixels each
equipped with a color filter (for details see Bayer filter). Although these
color filters work well in the visible, they may be rather transparent in the
near infra-red. By switching a webcam into the Bayer-mode it is possible to
access the information of the single pixels and a resolution below 3µm was
Effects on Modern Society
Webcams allow for inexpensive, real-time video chat
and webcasting, in both amateur and professional pursuits. They are frequently
used in online dating and for online personal services offered mainly by women
when camgirling. However, the ease of webcam use through the Internet for video
chat has also caused issues. For example, moderation system of various video
chat websites such as Omegle has been criticized as being ineffective, with
sexual content still rampant. In a 2013 case, the transmission of nude photos
and videos via Omegle from a teenage girl to a schoolteacher resulted in a
child pornography charge.
YouTube is a popular website hosting many videos made
using webcams. News websites such as the BBC also produce professional live
news videos using webcams rather than traditional cameras.
Webcams can also encourage telecommuting, enabling
people to work from home via the Internet, rather than traveling to their
The popularity of webcams among teenagers with
Internet access has raised concern about the use of webcams for cyber-bullying.
Webcam recordings of teenagers, including underage teenagers, are frequently
posted on popular Web forums and image boards such as 4chan.
Webcam Hacking and prevention
Most hackers use malware or remote administration
tools (RAT) to gain access to random users’ computers and then their webcams.
RATs are installed on a computer like a virus after
the user opens an infected file and are commonly shared on peer-to-peer (P2P)
file-sharing downloads. Attackers can use RATs to launch a user’s webcam and
watch them whenever they please. Once installed, the hacker can access private
data on the computer, restart the computer, and even open the CD/DVD tray.
Other forms of malware used to hack webcams can be
attached to phishing emails.
Luckily, there are quite a few steps you can take to
prevent this type of intrusion.
Make sure that you are using anti-virus or
anti-malware software on your devices – this goes for both computers and other
devices like tablets. Make sure the software is up to date and that you are
using the latest operating system available on your device to ensure you have
the best security possible.
Experts also recommend using a secure Wi-Fi
connection, which means ensuring you have a strong password on your home
It’s also important to note that most laptops, desktop
monitors and external webcams will have an indicator light showing when the
camera is on. If you notice the light come on when you aren’t using the camera,
it might be time to get your device looked at.
But, the easiest low-tech option to protect yourself
from webcam hackers is simply putting a piece of tape or paper over the camera
when you aren’t using it.