A CCD camera is any type of digital camera with a charge coupled device (CCD) image sensor. This includes the vast majority of consumer and professional still cameras, video cameras, security cameras, cell phone cameras and medical cameras. CCDs are very efficient, generally capturing about 70 percent of incident light, unlike photographic film which only responds to about two percent of incident light. CCDs are also sensitive to infrared light, which makes them ideal for night-vision surveillance cameras and astronomyapplications. While some cameras use a complementary metal-oxide semiconductor (CMOS) image sensor, the CCD is the most common type.
Most CCD cameras use a single charge coupled device to collect image data, whether the camera is designed for monochromatic, color or infrared operation. In this case, light enters through the lens, is filtered and then focused onto the surface of a single photoelectric image sensor array. Many professional video cameras, known as "three-CCD" or "three-chip" cameras, contain three CCD arrays. With these, the incoming light is split by a prisminto its red, green and blue components, each focused on its own CCD sensor. This improves color separation and increases light sensitivity, resulting in more accurate color shading in general and more detail in lower-light situations.
Fax machines, scanners and other types of linear-scan cameras use a one-dimensional CCD image sensor to gather data, moving either the sensor or the object being scanned in order to capture the entire image. Every other type of CCD camera uses a fixed two-dimensional area matrix. The CCD sensor is an array of coupled, photoactive capacitors which build up charges based on the intensity, duration and wavelength of the light being focused upon them. Once exposed to an image, the sensor's controller shifts the charge of each capacitor to its neighbor in the array. This creates a ripple effect across the whole matrix, shifting the last set of charges off-chip to a separate digitizer; this digitizer converts them into numeric values to be stored in the camera's memory.
