The Cameras in Your Computer

Long before services like Skype normalized the idea of the video-enabled telephone call, the classic spherical webcam was popping up on monitors around the world. The first webcam was the Trojan Room coffee pot camera – it provided 128x128 grayscale imagery of a coffee pot at Cambridge University. Its purpose? To keep researchers from making needless trips to an empty pot.

This camera was online and functional in 1991, two years before Web browsers had the capacity to display images. The first commercial webcam entered the U.S. in 1994: It had a 320x240 resolution with 16 shades of gray at 60 FPS or 256 at 15 FPS.

Today’s webcams are more advanced. Far from being eclipsed by smartphones, they are popping up more frequently for both business and pleasure.

Uses of webcams include:

Due to consumer demand, today’s webcams emphasize loss-free video and easy, one-click sharing. Although a webcam may seem simple, it is actually quite elegant.

Taking a Look Through – and Inside – Your Webcam

Early webcams used a charge-coupled device (CCD) for image capture, but today’s models often use a CMOS image sensor – like industrial cameras in the workplace. With instant image capture and transmission, it converts what it “sees” to digital format and instantly forgets it: There’s no RAM or flash memory on a typical webcam.

Because webcams focus on portability, they usually clock in at about one tenth the image depth of a digital camera. Although HD webcams are available, they still emphasize a high-compression video codec. As a general rule, every time there is a major advance in machine vision, it shows up in the technology of the humble webcam.

Inside, your webcam is little more than a plastic lens mounted onto a circuit board. As light hits the image sensor, data from each pixel is captured and converted into electrical signals. A CMOS sensor converts that data into a digital image within a single chip, while an old-fashioned CCD takes an analog approach, passing the signals to other chips for digitization.

CCD technology has been around since 1969 and was invented at Bell Laboratories – the CMOS image sensor, on the other hand, arises from work done at the NASA Jet Propulsion Laboratory in the 1990s. That’s a pretty sophisticated pedigree for something that is so common today!