How does your WebCam / CCD work ?

Principle of WebCam

A WebCam is a compact digital camera you can hook up to your computer to broadcast video images in real time process ( as they happen ) . Just like a digital camera , it captures light through a small lens at the front using a tiny grid of light-detectors , known as a charge-coupled device / CCD . As we shall see in a moment , the CCD (charge-coupled devices) converts the picture in front of the camera into digital format — a string of zeros and ones ( Binary Digits ) that a computer knows how to handle . Unlike a digital camera , a webcam has no built-in memory chip or memory card : it doesn't need to "remember" pictures because it is designed to capture and transmit them immediately to a computer or Laptop .

 Principle of a WebCam / CCD (charge-coupled devices) :

After removing outer case of a webcam you'll find it's little more than a plastic lens mounted directly onto a tiny electronic circuit board underneath . The lens screws in and out to increase its focal length , controlling the focus of your WebCam :
 

After Removing Case

 Now taking the lens off and you can see the light sensitive CCD chip , which is head of your webcam : it's the square thing in the middle of this circuit. Only the little , central part is light - sensitive : the rest of the CCD chip is concerned with connecting the light detector to the bigger circuit that surrounds it :

Micro Chip

How does a CCD convert an image to digital form?

When you capture a digital photo or stare into your webcam , light zooms into the cam lens . This incoming "picture" hits the CCD , which breaks it up into individual pixels . The CCD measures how much light is hitting at each pixel . This information is turned into a number that can be stored on a memory chip inside the camera . Thus , taking a digital photograph converts the picture you see into a very long string of binary numbers . Each number describes one pixel in the image - how bright or dark and which color it is .

Steps :

1. Light from the object (in this case ,here is a bicycle) enters in the camera lens .
2. The CCD inside the camera splits the image up into millions of pixels (squares). An LCD(Liquid Cristal Display) display on the back of the camera shows you a image that the CCD is capturing -- not an image of the object seen through a series of lenses ( as with a conventional camera ) , but a redrawn , computerized version of the original object displayed on a screen .
3. The CCD measures the color and brightness of each pixel .
4. The color and brightness are stored as binary numbers , patterns of zeros and ones , in the camera's flash memory card . When you connect your camera to a computer , these numbers are transmitted instantly down the wire . 

 The CCD was invented in the year 1969 by Canadian-born Willard S. Boyle  and American George E. Smith , two colleagues working at Bell Laboratories.

The scientific theory behind the CCD (turning light energy into electrical energy) dates back much further - to 1905. Known as the photoelectric effect , it was the first major scientific discovery by Albert Einstein .