How Does a Webcam Work on a Computer?

On the inside, webcams work in much the same way as a digital camera.

When you use a webcam, you are taking advantage of the technology in digital cameras. The device speeds up the transfer of photo and video data to broadcast media in real time. Your webcam employs several components to do this. Some are native to digital cameras; others require software and hardware elements on your computer.

Identification

A webcam is simply a basic digital camera that interfaces with software on your computer to broadcast video or pictures using the Internet. Webcams may be built into the computer itself; they also may be independent units that connect via cable to computers. Each webcam uses a digital camera lens, a circuit board embedded with a charge-coupled device chip and a software program that interfaces with a computer to perform these functions.

Interior Design

The part of the webcam most people immediately identify is the lens. This digital camera lens is attached to a circuit board. In the center of the circuit board is a chip full of sensors that detect light. This chip is called a charge-coupled device, according to scientist Chris Woodford. Also prominent are the screws mounted on either side of the lens; these move in and out of the until to move the lens closer and further away from an image, providing zoom in and zoom out capabilities.

The Lens and Charge-Coupled Device Chip

When you turn on a webcam, the lens takes in the image in front of the camera. That image is processed by a charge-coupled device. This chip, in the center of the circuit board behind the camera lens, is light-sensitive. The charge-coupled device breaks up the light taken in by the camera lens into millions of different pixels. The brightness and color levels of each pixel are measured by the chip, then translated into numeric code that your computer can read.

The Software Interface

Once the image seen by a webcam is converted into numeric code by a charge-coupled device, it is processed by the computer and displayed by any number of software programs that may be used to interface with a webcam, including the webcam's native software or a video chat program like Skype. Digital cameras use the same method, except the numeric code translated by the charge-coupled device is stored on a memory card, which transfers that information to the computer when the camera is connected. For webcams embedded in a computer or connected via USB cable, that translated data is immediately transferred to your computer and software programs, making live video chat or real-time webcam feeds possible as long as the device is turned on and connected.

References

• Explain That Stuff: Webcams
• Microsoft: Microsoft Home Magazine: Webcam Basics--How Do They Work?
• Explain That Stuff: CCDs (Charge-Coupled Devices)