How a Web Camera Works
From videoconferencing to checking on your house while on vacation, webcams have become a staple of Internet culture. Most new laptops come with a built-in webcam while anyone with an older computer can purchase a webcam for very little money. Cheap, convenient and easy to install, it's surprising that they didn't take over sooner.
The Basics
Essentially, webcams are digital cameras that you can connect directly to your computer. Both webcams and digital cameras capture the light that bounces off the subject, immediately breaking it down into electrical charges. Next, a charge-coupled device (CCD) converts the light into electrons. The charge is then read and transferred to an analog-to-digital converter (ADC), which converts the image into digital format (binary code).
Differences Between a Webcam and a Digital Camera
While digital cameras are designed to capture fine details (the higher the resolution, the sharper the image), webcams are specifically intended to capture images at a much lower resolution. This is so that the information is more compact and therefore easier to upload or send through the Internet. Webcam images are usually about one-tenth the size of those taken with digital cameras, but can form an even smaller fraction when compared to more complex digital cameras.
In the same vein, webcams have no built-in memory. Instead, a webcam transfers images directly to the computer it's connected to. If the camera isn't built in to the computer, this transmission happens via a USB cable.
Still Images
What really distinguishes Webcams and digital cameras, though, is the way they're used. Special software captures a frame from the camera at some interval, which the user sets, then converts it to a JPG file and transfers it to the selected location for viewing, uploading and sending the picture.
This capability is frequently used as a type of surveillance. Whether you want to check in on your pet while at work or let faraway family watch your kids open their presents on Christmas morning, freeze frames every few minutes are the way to go.
Streaming Video
With the emergence of video chatting as a major form of communication, webcam systems must now work more quickly than their more basic predecessors. Sending streaming video utilizes the exact same method as grabbing stills, it just happens much more quickly.
"Frame rate" refers to the number of still frames the software can freeze and send each second. Streaming video requires about 20 frames per second but an even higher frame rate means a more fluid, movie-like scene. In this case, not only do the software and hardware require more advanced capabilities but a high-speed Internet connection is also vital.
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