Don’t Be Fooled about Image Quality
The Facts about CCD and CMOS Sensors

Don’t have any idea what CCD and CMOS are? No problem. It’s simple. They are just two different types of image sensors. Why should you care? Because almost everyone owns a digital camera these days, and every digital camera contains an image sensor. Image sensors are also used in other popular devices such as video camcorders and interactive visualizers (document cameras).

How do CCD and CMOS sensors work?

Both CCD and CMOS sensors receive light through a lens. When light hits the pixels on the sensors, the light is converted into electrical charges. These electrical charges are then converted into voltage. Then the voltage is converted into digital information. This digital information is displayed through many different devices such as digital monitors and projectors.

What is the difference between CCD and CMOS sensors?

The difference between CCD and CMOS sensors lies within how they process light into voltage and then ultimately into digital information. A CCD sensor transfers the electrical charges from pixel to pixel and then converts them into voltage. Each of the pixels on a CMOS sensor contains a transistor. Therefore, each pixel receives light and converts the light into voltage.

History of CCD and CMOS sensors

Both technologies were invented in the late 1960s and early1970s. At the time, CMOS performance was limited by available lithography (process of producing a picture) and fabrication technology, allowing CCD sensors to dominate for many years. This lead people to believe devices with CCD sensors were better than one with CMOS sensors. It wasn’t until the 1990s when lithography and fabrication technology developed to the point where manufacturers could begin making CMOS sensors to compete with CCD ones.

Today, CCD and CMOS sensors both offer excellent imaging performance in regard to clarity and color. The applications of both types of sensors are many; thus, the choice to use one or the other depends on the application more than the technology.

Webcams Are Not Interactive Visualizers a.k.a. Document Cameras

We at AVerMedia know that there is currently a lot of technology for the classroom in the market. We also know that teaching trends and teacher demands are always changing. One of the many things we like to do at AVerMedia is to stay on top of the game, and recently we’ve found teachers talking about webcams and interactive visualizers in the same sentence. This is a no-no.

First of all, most of us have seen and/or used a webcam; therefore, I don’t need to tell you that you need to hook it up to a computer before you can start using the funny eyeball-looking device. Whereas, a visualizer is compatible with many common classroom devices such as computers, digital projectors, LCD monitors, and TV monitors. Additionally, since a webcam connects to a computer via USB, its frame rate is quite slow. Visualizers, on the other hand, generally provide a real-time frame rate of 24-30 frames per second.

OK. So you wouldn’t mind building a contraption to hold your webcam in a certain position before hooking it up to a computer. Even if you were successful at doing that, you’ll have to deal with mediocre image quality at best; you know…those fuzzy images. With a visualizer, you don’t need to worry about image quality or lag since they use the latest camera sensor technology.

There are a few other factors to consider as well. Webcams generally don’t have a zoom function. And if they do, the zoom is as powerful as a magnifying glass. On the other hand, visualizers come with excellent optical and digital zoom capabilities. Webcams also have a limited shooting area; substantially smaller than an A4-sized paper. This is not the case with visualizers as most can display an A4-sized paper all at once. And as a bonus, visualizers easily connect to microscopes so everyone sees the same information simultaneously. In addition, webcams offer little or no features while visualizers come with useful features like picture-in-picture, split screen, and freeze.